Issue 7 dec07

ASTRONOMY

TECHNOLOGY TODAY Your Complete Guide to Astronomical Equipment

FAR-SIGHT BINOCULAR MOUNTING SYSTEM • THOUSAND OAKS NEBULA FILTERS ADVANCED ALT-AZ TELESCOPE WORKSHOP • TEST DRIVING THE SSO DEMYSTIFYING MIRROR COATING TECHNOLOGY

Rich Williams The Making of the Sierra Stars Observatory

Volume 1 • Issue 7 December 2007 $4.00 US

Contents Rich Williams stands in his Sierra Stars Observatory next to the 0.61-meter f/10 Classical Cassegrain research-grade telescope/mount manufactured by Optical Mechanics, Inc. The telescope and high-precision CCD imaging instruments are housed in a custom built observatory utilizing a Technical Innovations PRO-DOME located at a dark sky site on the east side of the Sierra Mountains in Alpine County California. The location offers ideal weather conditions throughout the year without the predictable summer monsoonal season typically experienced farther south in Arizona and New Mexico.

ASTRONOMY

TECHNOLOGY TODAY Your Complete Guide to Astronomical Equipment

FAR-SIGHT BINOCULAR MOUNTING SYSTEM • THOUSAND OAKS NEBULA FILTERS ADVANCED ALT-AZ TELESCOPE WORKSHOP • DEMYSTIFYING MIRROR COATING TECHNOLOGY • TEST DRIVING THE SSO

Rich Williams The Making of the Sierra Stars Observatory

Editor’s Note

Astro Tips

8

68 Tips, Tricks and Novel Solutions

Features 26 The FAR-Sight Binocular Mounting System I Admit That I Am Addicted to Binoculars

By Allan Keller

11 THE INTERNATIONAL DARK-SKY ASSOCIATION Awards its First International Dark Sky Reserve 12 ASTRONOMY PRODUCTS SHOWS Astronomy Product Companies Invade the East Coast 14 BACKYARD OBSERVATORIES Now offering “Dobservatory” 15 OBSESSION TELESCOPES 18-inch UC Obsession

40 Test Driving The Sierra Stars Observatory Like Renting a Lamborghini While Owning a Pinto (Anybody Remember Pinto’s?)

By David Snay 48 Thousand Oaks Nebula Filters Necessities For Viewing Nebulous Objects in All Their True Glory

By Erik Wilcox

11 ADIRONDACK ASTRONOMY Shelyak Lhires Spectrographs

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Volume 1 • Issue 7 December 2007 $4.00 US

We’re Not Crazy, Really!

Industry News

PAGE

Cover Story

53 What Is A Revolution?

Texas Astronomical Society Hosts Advanced Alt-Az Telescope Workshop

By Max Corneau 60 Demystifying Mirror Coating Technology An Insider’s Look at the Mirror Coating Process

by James Mulherin

16 HOLIDAY SHOPPING SEASON Astro Deals Abound 16 SCOPETRADER Free Web-hosting For Amateur Astronomers

Astronomy TECHNOLOGY TODAY

5

Contributing Writers

Contents New Products

Max Corneau is Vice President and a Life Member of the Texas Astronomical Society of Dallas, a NASA/JPL Solar System Ambassador, and Senior Army Space Operations Officer. Max possesses a Master of Science Degree in Engineering from Boise State University, and has served as a visiting astronomer at the U.S. Naval Observatory in Washington, DC. His astronomical images can be seen at www.geocities.com/astrodad32

Allan Keller is a co-founder of Farpoint Astronomical Research and also of Optical Structures Incorporated. He is the designer and developer of the FAR-Sight mounting and targeting system.

James Mulherin is the President and Head Optician of Optical Mechanics, Inc. whose techniques for polishing optics and mirrors are the core of OMI’s expertise. James is also a key member of OMI’s professional observatory telescope development and installation team. James started the company after earning a Bachelor of Science in physics with minors in German and mathematics from the University of Iowa in 1991. James is an avid amateur astronomer who enjoys visual observing and attending regional star parties.

David Snay is a retired software engineer living in central Massachusetts. He graduated from Worcester Polytechnic Institute and has been an astronomer and astrophotographer for more than 10 years. David currently pursues fine art photography, specializing in traditional black/white images.

18 VIXEN OPTICS Atlux Equatorial Mount with Star Book Controller 18 ASTRO HUTECH New IDAS RS Filters 21 CLEMENT FOCUSER 2.25-Inch Bellerophon III Focuser 22 ASTRO-PHYSICS Introduces “el Capitan” 3600GTO German Equatorial Mount 23 STELLAR TECHNOLOGIES INTERNATIONAL Introduces CVF Series II 24 KHAN SCOPE CENTRE Sky-Watcher EQ3 SynScan Go-To Mount and iOptron SmartStar Alt-Az Mount

Rich Williams has a varied technical background with stints at Raytheon, Wang Laboratories, Boeing and Microsoft as well as being co-founder of Optical Mechanics, Inc. He has a lifelong passion for astronomy and his creation of the Sierra Stars Observatory is the culmination of his efforts to create a world class observatory that anyone can use.

Erik Wilcox works for a natural foods distributor in South San Francisco,

California, and is a long-time moderator on the popular astronomy forum, “Cloudy Nights.” He enjoys star parties and public outreach and, in addition to amateur astronomy, he spends his time playing in a rock band.

Subscribe Now! Pay Only $18 Per Year and Get 12 Issues Covering the Latest in Technology

www.astronomytechnologytoday.com 6

Astronomy TECHNOLOGY TODAY

25 KENDRICK ASTRO INSTRUMENTS Offers New FireFly Heaters and Upgraded Premier Power Controller

ASTRONOMY

TECHNOLOGY TODAY

Volume 1 • Issue 7 December 2007 Publisher Stuart Parkerson

Managing Editor

Editor’s

Note

Gary Parkerson, Managing Editor

Gary Parkerson

We’re Not Crazy, Really!

Associate Editors Russ Besancon Karol Birchfield Jessica Parkerson

Art Director Lance Palmer

Staff Photographer Jim Osborne

Web Master James Bobbit

3825 Gilbert Drive Shreveport, Louisiana 71104 info@astronomytechnologytoday.com www.astronomytechnologytoday.com Astronomy Technology Today is published monthly by Parkerson Publishing, LLC. Bulk rate postage paid at Dallas, Texas, and additional mailing offices. ©2007 Parkerson Publishing, LLC, all rights reserved. No part of this publication or its Web site may be reproduced without written permission of Parkerson Publishing, LLC. Astronomy Technology Today assumes no responsibility for the content of the articles, advertisements, or messages reproduced therein, and makes no representation or warranty whatsoever as to the completeness, accuracy, currency, or adequacy of any facts, views, opinions, statements, and recommendations it reproduces. Reference to any product, process, publication, or service of any third party by trade name, trademark, manufacturer, or otherwise does not constitute or imply the endorsement or recommendation of Astronomy Technology Today.

The publication welcomes and encourages contributions; however is not responsible for the return of manuscripts and photographs. The publication, at the sole discretion of the publisher, reserves the right to accept or reject any advertising or contributions. For more information contact the publisher at Astronomy Technology Today, 3825 Gilbert Drive, Shreveport, Louisiana 71104, or e-mail at info@astronomytechnologytoday.com.

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Astronomy TECHNOLOGY TODAY

We get lots of mail, even a few messages that asked bluntly, “Are you crazy?” While the honest answer ranges between “sometimes” and “often,” it’s not for the reasons that those who inquire must think. Some opine that publishing any astronomy related print magazine in this digital, online age is prima facie evidence of psychosis, but the act that most often prompts this query is our favorable mention of other astro publications, particularly Amateur Astronomy and AstroPhoto Insight. The question assumes that subscribing to an astronomy publication is an either/or proposition and we strongly reject that view. ATT is designed for those who, like us, can’t get enough of this stuff; who visit the newsstand, see 50 plus titles devoted to photography, and regret the relative paucity of astronomy coverage in those same stacks.

Most nights find me in the backyard staring through a telescope. Unfortunately, conditions aren’t always perfect for an entire night and, while waiting for clouds to pass, or just to warm up, I sit for a while in front of the television killing time (with eyepatch protecting dark adaptation of my dominant eye, like some deranged, nocturnal, misplaced suburban pirate – Arrr!) There’s little on at 3 am other than infomercials and – you know what? – I haven’t seen one yet that promised to make you or me rich in the lucrative field of astro-business. Real estate? – of course. eBay? – you betcha! Telescope manufacturing?

Uh…say what? The fact is no one gets rich quick designing, making, or covering astronomy products.

Fortunately, the folks who serve this industry find plenty of reasons to do what they love, despite bottom line challenges. I was reminded of this unique aspect of this industry when I attended the Advanced AltAz Telescope Conference in Dallas last month

(see Max Corneau’s coverage of the event in this issue). The principals of several leading astro-businesses traveled at their own expense to attend the conference, with no prospect of ever making a dime for their participation in that project. Indeed, the goal of the workshop was to do the R&D necessary to making an advanced, research quality, half- to one-meter telescope design available to astronomy enthusiasts at the lowest possible cost – a design that will, in some cases, compete with instruments that these same participants produce and market.

I had a chance to visit at length with Dan Gray of Sidereal Technology during a break in the conference and found myself apologizing for providing a disproportionate amount of space in previous issues of this publication to the exceptional StellarCAT products, while managing very little mention of Sidereal Technology’s offerings. Dan’s immediate response was, “What’s wrong with that?” For a former commercial litigation attorney who’s more familiar with helping business competitors secure the slightest advantage over their fellows, it took a moment for Dan’s meaning to sink in. Dan, whose passion is applying his considerable skills to telescope automation, is also a fan of Gary Myers’ StellarCAT products. Go figure. As for Gary, I last visited with him at the Texas Star Party in May and, wearing my pushy editor hat, encouraged him to contribute an article about the unique innovations of his go-to/track systems. Gary’s response? – “I don’t know that I’d be comfortable tooting my own horn.” A misplaced concern, but - go figure again.

Learning at the Dallas event that Dave Rowe not only “donated” his Corrected DallKirkham design to the project, but that he had also lent his efforts to several significant refinements to Sidereal Technology’s feature rich controller software, should have come as

no surprise. Nor should I have wondered when Cary Chlebodrad, of Optical Structures fame, volunteered to provide CAD patterns for structural parts of the project scope so that those who build their own can have the fabrication done locally to save costs, despite that Optical Structures is in the business of fabricating research quality telescope structures.

Go figure a third time.

Many of you who’ve met Scott Roberts know him as the man who puts a very personal face on Meade’s participation in a surprisingly large number of events each year.

What you may not know is that Scott devotes a great deal of his private time and resources to organizing and promoting some of the industry’s most effective outreach efforts. I can personally attest to the selflessness with which Scott approaches both his job and his private efforts to make astronomy and its tools more accessible to a new generation of potential enthusiasts. The industry’s habit of community largess infects even its largest participants.

And I could list many more examples.

Indeed, this industry is by and large a collection of refreshingly unselfish artisans dedicated to producing high quality products, often at ridiculously low prices. Any of these folks could make far more money pursuing products that attract much larger markets, but that’s not where their hearts are.

So no, we’re not crazy to help promote Amateur Astronomy and AstroPhoto Insight, or S&T and Astronomy for that matter.

We’re simply trying to adopt the better habits of the industry we cover. Plus, it just makes perfect, selfish sense. We’re not in economic competition with any other publication – frankly, there’s too little economy to contest.

Instead, we want each to prosper and grow because if they don’t, we won’t have them to enjoy.

What’s crazy is sitting in my living room at 3 am, wearing an eyepatch over one eye and my ScopeStuff Red Observers Glasses (Item RGLA – $11 shipped!) over both, watching infomercials promising to free me of these strange habits with three monthly credit card investments in the secret to becoming an eBay millionaire. Almost as crazy as a sleep deprived, aging gentleman atop a 10-foot, three legged ladder, in the dark, wearing said eyepatch and thus lacking depth perception, trying to “pogo” the ladder a few inches to the right because he’s too tired to make the round trip down and up the thing one more time.

We’re not crazy, really!

The new Astro-Physics 6" Eagle Adjustable Folding Pier is a versatile work-of-art as well as a totally practical tool for the advanced imager.

The one piece assembly sets up quickly in the field and allows adjustment of pier height, leveling of the mount, and eases the process of polar alignment.

www.astro-physics.com • 815-282-1513 Astronomy TECHNOLOGY TODAY

9

The Supporting

CAST

The Companies And Organizations That Have Made Our Magazine Possible!

We wish to thank our advertisers without whom this magazine would not be possible. When making a decision on your next purchase, we encourage you to consider these advertisers’ commitment to you by underwriting this issue of Astronomy Technology Today.

Blue Planet Optics www.blueplanetoptics.com page 72

Meade Instruments www.meade.com page 4, 69

Sierra Stars Observatory www.sierrastars.com page 61

Bobs Knobs www.bobsknobs.com page 32

Obsession Telescopes www.obsessiontelescopes.com page 50

SkyShed Observatories www.skyshed.com page 47

Catseye Collimation www.catseyecollimation.com page 24, 39

Oceanside Photo and Telescope www.optcorp.com page 56

Celestron www.celestron.com page 2, 28, 71

Optec www.optecinc.com page 24

CNC Supply www.cncsupplyinc.com page 57

Optical Mechanics www.opticalmechanics.com page 21

Denkmeier www.denkmeier.com page 62

Optical Wave Laboratories www.opticwavelabs.com page 16

Durango Skies www.durangoskies.com page 45

Ostahowski Optics www.ostahowskioptics.com page 24

Astro Hutech www.hutech.com page 10

Farpoint Astronomical Research www.farpointastro.com page 11

Peterson Engineering www.petersonengineering.com page 63

AstroPhoto Insight Magazine www.skyinsight.net page 36

Glatter Collimation www.collimator.com page 44

Astro Physics www.astro-physics.com page 9,42

Great Red Spot Astronomy www.greatredspot.com page 61

Rigel Systems www.rigelsys.com page 18

AstroShorts www.astroshorts.com page 66

HyperTune http://lxd55.com/hypertune page 47

ScopeBuggy www.scopebuggy.com page 34

Woodland Hills Telescopes www.whtelescopes.com page 14

AstroTrac www.astrotrac.com page 51

Jack’s Astro Accessories www.waningmoonii.com page 33

Scope Stuff www.scopestuff.com page 63

William Optics www.williamoptics.com page 3

ATS Piers www.AdvancedTelescope.com page 43

JMI Telescopes www.jmitelescopes.com page 13

Scope Trader - Sites www.scopetrader.com/sites page 63

Van Slyke Instruments www.observatory.org page 17

Backyard Observatories ww.backyardobservatories.com page 35

Khan Scope Centre www.khanscope.com page 63

Shrouds By Heather www.teeterstelescopes.com/shrouds page 25

Zeke’s Seats foxworks@netscape.com page 43

20/20 Telescopes and Binoculars www.2020telescopes.com page 19 Adirondack Astronomy www.astrovid.com page 49 Agena AstroProducts www.agenaastro.com page 27

Amateur Astronomy Magazine www.amateurastronomy.com page 38 APM Telescopes www.apm-telescopes.de page 52 Astro Domes www.astrodomes.com page 38 Astro Gizmos www.astrogizmos.com page 64

ProtoStar www.fpi-protostar.com page 57

Starizona www.starizona.com page 16 Stark Labs www.stark-labs.com page 33 Starlight Instruments www.starlightinstruments.com page 12 Stellar Technologies International www.stellar-international.com page 67 Stellarvue www.stellarvue.com page 41 Surplus Shed www.surplusshed.com page 20 Tele Vue Optics www.televue.com page 70 Teton Telescope www.tetontelescope.com page 23 Thousand Oaks Optical www.thousandoaksoptical.com page 57

TO ADVERTISE CONTACT advertise@astronomytechnologytoday.com

INDUSTRYNEWS

ADIRONDACK ASTRONOMY

THE INTERNATIONAL DARK-SKY ASSOCIATION

Introduces Shelyak Lhires Spectrographs to North American Market

Awards its First International Dark Sky Reserve

Adirondack Astronomy has always sought to bring unique products to the North American astronomical market and the highly regarded Shelyak Lhires Spectrographs from Shelyak Instruments of Revel France are the latest examples.

The Shelyak Spectrographs, the Lhires III and Lhires Lite, are currently in use around the world.

The Lhires III is especially well suited for use by schools, colleges, universities, and the intermediate to advanced amateur

The International Dark-Sky Association (IDA) awarded its first International Dark Sky Reserve (IDSR) designation to the regional county municipalities of Granit and Haut-Saint-François and of the City of Sherbrooke, an area of 5,500 square kilometers in Québec Province, Canada.

The IDSR will preserve night sky quality and ensure the sustainability of education and research activities at the Mont-Mégantic Observatory, the most important astronomy and astrophysics research center in Canada.

The IDA defines an International Dark Sky Reserve as a public or private land possessing an exceptional or great quality of starry nights and nocturnal environment that is specifically protected for its scientific, natural, educational, cultural, heritage and/or public enjoyment mission on a large peripheral area. The Dark Sky Reserve con-

sists of a core area meeting the minimum criteria for sky quality and natural darkness, and a peripheral area that supports dark sky values in the core and benefits from them, as well.

The reserve's 34 municipalities developed outdoor lighting regulations that have contributed to the control and limited growth of area light pollution, which had doubled over the past 20 years. Additionally, approximately 2,500 lighting fixtures were replaced, resulting in a 25% reduction of area light pollution and a 1.3 gigawatt-hours per year savings in energy consumption.

The International Dark-Sky Association, an educational, environmental nonprofit, is dedicated to protecting and preserving the nighttime environment and our heritage of dark skies through quality outdoor lighting. For more information go to www.darksky.org.

astronomer who wants to pursue real scientific work with either a digital SLR or conventional CCD camera. The Lhires III is a proven, versatile spectrograph system that can be adapted for all types of spectroscopic work. There are various resolution grating modules available for comets, deep sky objects and stellar spectra.

Lhires Lite spectroscope is a visual only version of the Lhires III. It is a unique visual solar spectrograph that will show the sun’s spectra in stunning color detail. It will reveal thousands of the absorption lines that are the signatures of the chemical composition and physics of the solar photosphere. No telescope is required when using Lhires Lite; only a tripod is needed.

For more information go to www.astrovid.com Astronomy TECHNOLOGY TODAY

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INDUSTRYNEWS

ASTRONOMY PRODUCTS SHOWS Astronomy Product Companies Invade the East Coast While it was not an actual invasion, several well known astronomy companies located in sunny California made the trek to the east coast in October to enjoy the fall colors and show off the newest in telescope technology.

Representatives from Celestron, Coronado, Meade, and Stellarvue descended on Damascus, Maryland, the home of Hands On Optics, for the First Annual Eastern Telescope Show on Saturday, October 13. Of course they came with lots of astro stuff to show off to the attendees.

In addition to the displays and demonstrations of astronomy products, the event included presentations from Vic Marris of Stellarvue, Hands On Optic’s Patrick Ramsey and Jim Chen, and renowned solar astronomer Greg Piepol.

Of course, the most popular part of any astro products show is the raffle prizes, which did not disappoint.

Several thousands of dollars in astronomy equipment were given away including a Stellarvue 80-mm Nighthawk II donated by Stellarvue, a Meade Deep Sky Pro with Filters donated by Meade Instruments, a Celestron SkyScout donated by Celestron, and numerous other prizes donated by Gary Hand, owner of Hands on Optics.

A short three hours away from Damascus, the California contingent converged on Pottstown, Pennsylvania, the headquarters of Skies Unlimited, for the Mid-Atlantic Astronomy Expo 2007 on Saturday, October 20.

Joining Celestron, Coronado, Meade, and Stellarvue was another California headquartered astro products company, Vixen Telescopes. The East Coast was also well represented

12

Astronomy TECHNOLOGY TODAY

by Tele Vue Optics.

Once again 100’s of attendees were treated to displays and demonstrations of the latest astronomy products. The event also featured a luncheon presentation by Stellarvue’s Vic Maris, Tele Vue Optics’ Al Nagler, and Vixen Optics’ Mike Fowler. The folks at Skies Unlimited report that attendees traveled from far and wide and even included one gentleman who drove all the way from Kentucky.

And yes, there were again thousands of dollars in raffle prizes given away, including a Tele Vue Ethos Eyepiece donated by Skies Unlimited, a Vixen R130SF Telescope on Porta Mount donated by Vixen Optics, a Stellarvue Nighthawk Refractor donated by Stellarvue, a Meade mySKY donated by Meade Instruments, a Celestron Sky Scout donated by Celestron, and a Tele Vue 13-mm Nagler donated by Tele Vue Optics.

Mike Fowler of Vixen Optics poses with the happy prize winner of a Vixen R130SF Telescope on Porta Mount.

Stellarvue’s Vic Marris demonstrates a Nighthawk Refractor.

INDUSTRYNEWS

BACKYARD OBSERVATORIES Now Offering “Dobservatory”

Rebate Up to $200 on Your Favorite ETX or Truss Tube!

Rebate Up to $200 on Your Favorite Nextar SE Telescope!

New Lower Prices!

Plossl 8, 11, 15mm ....................$74 20, 25mm ........................$86 32, 40mm ........................$103 55mm ..............................$204 Radian 3, 4, 5, 6, 8, 10, 12, 14, 18mm ..............................$219 Zoom Nagler 2-4mm.................$335 3-6mm .............................$344

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Panoptic 41mm ...............................$444 35mm........$331 27mm........$300 24mm........$270 22mm........$248 19mm........$213 15mm........$215 Nagler Type 5 31mm......................$557 20mm ........$342 16mm........$287 Nagler Type 4 12mm......................$318 17mm ........$344 22mm .......$418 Nagler Type 6 13, 11, 9, 7, 5, 3.5, and 2.5mm ..........................$252 Zoom Dioptrix................................$209

Astronomy TECHNOLOGY TODAY

Scott and Diane Horstman of Backyard Observatories continue to demonstrate why they are among the leaders in roll-off roof observatory innovation with their recently introduced “Dobservatory.”

The new observatory is specifically designed to accommodate the low pivot point of Dobsonian reflectors, allowing the user to view near the horizon. The design offers a 3-foot 6-inch wall height when the roof is rolled off, which is perfect for viewing those faint fuzzies low in Sagittarius! Other designs either block the Dob user’s view or require that the telescope be put on a raised platform.

When closed the Dobservatory’s vaulted ceiling design and 5-foot wall height allows for plenty of head room and the pleasing aesthetics of Backyard Observatories’ other roll-off roof observatories. The Dobservatory is available in the same sizes as BYO’s home model observatories, up to 15-foot 6-inch x 15-foot 6-inch.

BYO builds its observatories with standard residential style construction – just like a house, not like a shed. Vinyl siding is generally used, but any type of siding can be substituted to best achieve the look you want. The Dobservatory is yet another innovative design from one of the first and most experienced builders of commercially available roll-off roof observatories.

For more information, please visit www.backyardobservatories.com.

INDUSTRYNEWS

OBSESSION TELESCOPES 18-inch UC (Ultra Compact) Obsession Now Available

In the May issue of ATT we announced that Dave Kriege of Obsession Telescopes had debuted a prototype of his new 18-inch UC (Ultra Compact) Obsession at the Texas Star Party.

We are excited to announce that the 18-inch f/4.2 UC production model is now available. The entire concept for the Ultra Compact is to maximize transportability. It is designed around a “Virtual Mirror Box” which features a supporting frame that offers a rigid assembly of folding side bearings and a standard Obsession open tailgate mirror mount that is reversed from its normal orientation.

“The new 18-inch f/4.2 UC is a revolutionary design. It is a large aperture telescope that collapses into a very small package. If you have limited hauling or storage capacity, (like the trunk of a small car) then this is the scope for you,” says Dave.

“In the transport mode the clearance height is a mere 14 inches. Or place the VMB (Virtual Mirror Box) next to the

rocker in your car and reduce the height even more. Now everyone can have a big aperture scope and take it to their dark sky site. This telescope will appeal to those who like the ultimate in form-follows-function style. Lower eyepiece height means 90% of observing will be done with your feet on the ground. The UC is all black with a modern space frame construction. If your vehicle is small or you intend to put it in the trunk, then the Ultra Compact is the obvious choice. And if you want the ultimate in Dobsonian evolution, the Obsession Ultra Compact 18inch is it.”

Dave continued, “We use the same premium optics from Galaxy and OMI that we do in our Classic series of telescopes. The mirrors are diffraction limited and all figured and tested with interferometry with Ion deposition 96% enhanced primary coating. With 2-inch flex free glass and one tenth wave 98% Diamond brite secondary mirror, you cannot get better optics at any price anywhere.”

Standard options and accessories include a Feathertouch focuser by Starlight Instruments, Telrad, external light baffle, counterweight kit, wheelbarrow handles, enhanced aluminum primary mirror coating - 96% reflectivity, with dielectric overcoat (a supreme coating), super enhanced brilliant-diamond secondary mirror premium multi-dielectric coating that has 98% reflectivity at 550 nm. With 96% enhanced on the primary and the 98% Brilliant Diamond secondary, the optical system offers the equivalent to an extra 2 inches of aperture.

Optional accessories include a 26inch by 26-inch by 20-inch thermo-

formed high-density polyethylene white travel case that meets Air Transport Association’s (ATA) Specification 300, Category 1 requirements. Other accessories include a Paracorr, ripstop nylon light shroud, Barlow-laser collimator (2inch barrel which includes a 2-inch magnetic Barlow lens), Argo Navis digital setting circles with super res 10K encoders, and ServoCAT Goto Drive System (available early 2008).

For more information go to www.obsessiontelescopes.com.

18-inch UC Specifications Primary Mirror: 18" (457 mm) GALAXY, or OMI 2 inch thick mirror, 96% reflectivity Enhanced Aluminum Coating and Dielectric Overcoat (a supreme coating), Center marked for precise collimation; plus Interferometry certification Secondary Mirror: 3.1" (79 mm) United Lens 1/10 wave or better, Interferogram included, 98% reflectivity at 550 nm, Super enhanced Brilliant-Diamond nonfading multi-dielectric coating Focal Length: 75" (± 2") [1905 mm (± 50 mm)] Mirror Cell: 18-point Truss Pole: Length: 55" (± 2") [140 cm (± 5 cm)], Diameter: 1.25" (32 mm), Wall Thickness: 0.035" (0.9 mm) Upper Assembly: Diameter: 22" (56 cm), Height: 13.5" (34 cm), Weight: 6 lbs. (2.7 kg) Lower Assembly: Virtual Mirror Box alone folded for Transport - 22" x 25" x 12" high, Virtual Mirror Box stacked in Rocker for Transport - 25" x 25" x 13.5" high Eyepiece Height at Zenith: (approximately) 70" (178 cm) Weight of Complete Scope: Approximately 90 lbs

Astronomy TECHNOLOGY TODAY

15

INDUSTRYNEWS

HOLIDAY SHOPPING SEASON Deals Abound on Astronomy Products The holiday shopping season represents a time to get some of the best deals of the year. The astronomy products industry is no exception and you will find incredible pricing on astro stuff everywhere.

It would take hundreds of pages to cover all of the great deals that are out there - all you have to do is visit the website of your favorite astro products dealer. We found some unbelievable deals being offered for the holidays and we

suggest you check them out for yourself!

For example, as we mentioned in last month’s issue, Tele Vue Optics is currently offering a 13% discount on eyepieces, Powermates, Barlows and Dioptrx through December 28. These discounts are available from any retailer in its dealer network.

In addition to special pricing, there are several manufacturers offering specific rebates for the holiday season. For example, Celestron is offering up to a $200 rebate on its NexStar SE line of computerized telescopes. Celestron is also offering a $50 rebate on the SkyScout Personal Planetarium.

Meade Instruments is offering a $200 rebate on the purchase of its ETX90 or ETX-125 when combined with a mySKY. Meade is also offering up to a $200 rebate on its line of LightBridge Dobs. You will also enjoy a $100 rebate on the Coronado PST for a limited time.

Vixen Optics is offering rebates of from $200 to a whopping $500 on its ED81SWT, ED103SWT, ED115SWT and NA140SS Telescopes.

We are already making our list, and checking it twice.

Happy Holidays!

SCOPETRADER Free Web-hosting For Amateur Astronomers

ScopeTrader has announced SITES, its free website hosting service to amateur astronomers. SITES is essentially a website building engine that provides an easy to use interface that assists amateurs in carving out their own “space” on the Web. The system creates a unique domain name for each user that it hosts.

ScopeTrader’s ambitious goal for SITES is to gather the largest database of amateur astronomer websites on the Internet.

Best yet, the system is completely free to all users. For information visit www.scopetrader.com/sites.

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Astronomy TECHNOLOGY TODAY

NEWPRODUCTS

VIXEN OPTICS

ASTRO HUTECH

Atlux Equatorial Mount with Star Book Controller

New IDAS RS Filters

The new Vixen Altux Mount is a midsized go-to equatorial mount newly designed to work with the Vixen Star Book Hand Controller. The mount is designed and manufactured to offer the highest slewing and tracking performance in an easily transportable package.

The Atlux features celestial navigation with the Star Book and includes PEC and Autoguider functions. The Atlux is styled with minimal protrusions and the counterweight shaft is retractable for ease of transport and storage. With a maximum load weight of 75 pounds, the Atlux is an ideal, solid platform for long exposure astrophotography.

The Vixen Star Book features and menu options are displayed on the large color screen and are easily navigated with a simple button layout on the controller. The Star Book, which has a database of over 22,000 objects, is easy to use – its full color screen is a detailed star chart that acts as a navigational and go-to guide for the mount. The zoom in and out buttons for the star chart display also control the motor speed.

As a user zooms in closer to an object on the display screen, the

motor speed automatically becomes finer and as they zoom out, the motor speed increases to cover larger distances more quickly. The Star Book is amazingly easy to use and makes the Atlux available to a wide range of user ages and experience levels.

For more information go to www.vixenoptics.com.

Atlux Mount Features R.A. Slow Motion Axis: 180 tooth wheel gears whole circle movement.

DEC Slow Motion Axis: 180 tooth wheel gears whole circle movement.

R.A. Coordinates Display: On the screen of STAR BOOK in 0.1 arc minute increments.

DEC Coordinates Display: On the screen of STAR BOOK in 0.1 arc minute increments.

Polar Axis Scope: 6x20mm, wide 8degree field of view.

Altitude Adjustment: 0 to 72 degrees (2 degree increments, 3 step elevation).

Azimuth Adjustment: Double-screw fine adjustment.

Telescope Control System: STAR BOOK. Power Source: DC12 volts, 0.4 to 1.7 amperes.

Maximum Loading Weight: 75 lbs.

Counterweights: 7.71 pounds (3.5 kg) x 1 and 15.4 pounds (7 kg) x 1.

Weight: 43.4 pounds (19.7 kg), without counterweight.

NEW! QuikAdapt

PulsGuide + 12.5 mm Guiding Eyepiece PulsGuide pulses reticle illumination to let eye rest between pulses, for increased contrast between reticle & faint guide stars. The result? Easier guiding. Eyepiece has excellent eye relief & sharp double cross hairs.

$79.95

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Astronomy TECHNOLOGY TODAY

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TECHNOLOGY TODAY

Skylite & Starlite mini

Our original astro flashlight, much imitated but never duplicated, is back! More compact at only 3.5 inches long. Skylite switchable between white and red, Starlite is red only. Skylite mini $24.95 Starlite mini $20.95 $119.95

nFOCUS + focus motor

Universal digital camera adapter for Astrophotography. for both eyepiece projection & prime focus. Works with digicams and DSLRs. One handed easy-on & easy-off, easy camera alignment, rigid durable aluminum.

Hutech and IDAS Japan have announced the introduction of an innovative new set of RGB filters utilizing the unique IDAS RS (Reflection Suppression) technology which minimizes annoying reflections around bright stars in CCD images.

The IDAS RS technology filters are specifically designed to address the problem of internal reflections common in filtered CCD images when bright stars are present in the field of view (especially common in wide-field images). The IDAS RS filter set reduces surface reflections to less than 4% of conventional dichroic filters.

The complete set IDAS RS includes 4 filters – luminance(L) and RGB components. An optional Cyan filter is available for OIII emission line nebulae imaging.

Two geometries are available which are suitable for even the large sensors available today – 50-mm round and 50-mm square. Astro Hutech estimates that the new IDAS RS filters will be available by the end of 2007.

For more information go to www.hutech.com.

NEW! RS-Spectroscope

Attaches to a eyepiece to spreadlight from stars and nebulae into a rainbow of colors, nFOCUS controller fits in the palm colors that provide a whole new way to of your hand and provides two enjoy astronomy. Works with most directions at low & high speeds with digital cameras. $299.95 only two buttons using advanced logic & high torque 12V pulse.

QuikFinder $39.95 For GSO, Stellarvue, WO &Televue. Compact reflex sight. One tenth the size and nFOCUS alone. $49.95 nFOCUS + DC Motor $129.95 weight of the other "reflex" sight, makes aiming your telescope easy with its wide-open right-side-up view. Projects 1/2 and 2 degree red circles, Pulsed or continuous illumination of reticle. www.rigelsys.com

Rigel Systems

NEWPRODUCTS

CLEMENT FOCUSER Survives California Wildfires, 2.25-inch Bellerophon Focuser Coming Soon Image 1

Clement Focuser calls Running Springs, California home. This small community of 5,125 is located at an elevation of 6,000 feet in the San Bernadino Mountains about 90 miles east of Los Angeles. Running Springs lost 201 homes to the recent Southern California wildfires and was subject to an extended mandatory evacuation order.

Although the October evacuation orders for the area have been rescinded, conditions

These events have delayed introduction of the latest addition to the Clement Focuser line, the soon to be available 2.25-inch Bellerophon III that will replace Clement's 2inch DL2006 Focuser. The new 2.25-inch version is specifically designed to better accommodate CCD imaging. The patented Clement Focusers are precision positioning devices that employ non-stiction flexural bearings for precise, repeatable, ultra smooth Image 3

Image 2

there remained hazardous when we last spoke to Don Clement on November 13, 2007.

Don reported that, although he and his family were recently permitted to reoccupy their home and business property, isolated fires are still breaking out in the area, primarily from below ground roots that continue to burn. Apparently the risk of fires from such sources will remain very high until the area experiences substantial rain or snow. Don also reported that, although they were permitted to return to their property after 10 days, the area was without phone service as late as the second week of November.

both ends by all-compliant supports) micrometer leadscrew. When used with Robo-Focus and Auto Focus Software, the path to focusing converges with perfect linearity eliminating nonlinear behavior. A variety of mounting accessories will be available for the new Clement focuser and custom adapters are available to meet special needs.

Of course, Clement's recently introduced 3-inch Bellerophon II is still available and offers even greater capacity. It features a load capacity of 15 pounds with the same 1.5-inch travel and ultra-low one-inch profile of the Bellerophon III. Image 1 shows the Bellerophon II with 2-inch to 3-inch adapter removed. The 2-inch eyepiece shown in Image 2 is held securely by the 2-inch to 3inch adapter using two 1/4-inch knurled head bolts and an extra-wide 3/8-inch brass compression ring. Image 3 shows the Bellerophon II mounted on a Celestron C14 using the new Split-Clamp Mounting Adapter shown in Image 4. For more information go to www.clementfocuser.com.

movement. Focus position is determined by the use of a single zero backlash, non-rotating micrometer leadscrew.

As its name indicates, the new Bellerophon III Focuser offers 2.25 inches of clear aperture and, like all previous Clement designs, provides more than enough load capacity to handle far more than typical CCD imaging assemblies require. It provides 1.5 inches of travel, with an ultra-low profile of just one inch that minimizes overhang and vignetting. Ultra-linear focusing is made possible by use of a single floating (supported on Image 4

Astronomy TECHNOLOGY TODAY

21

NEWPRODUCTS

ASTRO-PHYSICS Introduces “el Capitan” 3600GTO German Equatorial Mount at AIG 2007 We won’t say that the folks at AstroPhysics are sneaky, but they were able to sneak by us the top secret development of the new “el Capitan” 3600GTO German Equatorial Mount! AP debuted el Capitan at the recent Advanced Imaging Conference (AIC) in San Jose, California to rave reviews!

Originally designed to carry a large telescope in Antarctica for planetary research, Marj Christen of Astro-Physics reports that the 3600GTO mount had to be reliable in the most severe environment on the planet and function flawlessly 24 hours per day for the entire polar night lasting 6 months. Once the mount is installed and the polar night begins, no maintenance can be done to the mount due to the extreme low temperatures and dangerous wind conditions that prevent technicians from working outdoors.

Astro-Physics smaller mounts have proven themselves in these frigid Antarctic conditions over the past 3 years. They have had a number of 900GTO and 1200GTO mounts running continuously at Dome C in Antarctica. In fact, AP mounts count among the very short list of equipment that actually works under those conditions, where the temperature is so cold that optics shatter and paint falls off tube assemblies. AP used the same design philosophy that has overcome these harsh conditions for the 3600GTO.

The mount was designed to offer a large, robust, rugged, simple modular design using Astro-Physics time-proven components that have held up under the extraordi-

nary conditions, even in temperatures as cold as -70C. It offers simple mechanics that make adjustment easy and accurate with an extremely smooth and accurate dual servomotor-worm gear drive, designed for all astro-imaging situations. The mount offers the ability to easily carry very large and heavy scopes with many options for enhancing the operation and accuracy of the mount for remote imaging.

Specifications of Equatorial Head Worm Wheels: Aluminum, 13" (330mm), 256 teeth.

Worm Gears: Brass, 1.41" (35.8mm) diameter.

Axis Shafts: 4.72" (120mm) diameter with 4.02" (102mm) clear inside diameter.

Axis Bearings: 7.09" (180mm) diameter deep groove ball bearings.

Worm Gear Bearings: 1.57" (40mm) angular contact ball bearings.

Latitude Range: 15 to 70 degrees.

Azimuth Adjustment: Approximately 14 degrees (+/- 7 deg.).

Motors: Swiss DC servo controlled - 2 motors per axis.

Capacity: Approximately 250 pounds (113kg) scope and accessories, depending on length.

Weight Equatorial Head: (without counterweight shaft or counterweights) 205 pounds (93 kg), Dec. axis is 84 pounds (38kg), RA axis and base assembly is 121 pounds (55kg). Weight Counterweight Shaft (estimated): 30 pounds (14kg).

Optional Saddle Plate: 12.9" x 22" (328 x 559mm), 15 pounds (7kg), dovetail receiver with four integrated clamps, safety slots and bolt-through locking feature.

Optional Dovetail Sliding Plate: 9.9" x 22" (251 x 559mm), 9 pounds (4kg) with universal hole patterns and safety stops.

Optional auxiliary control panel available.

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Astronomy TECHNOLOGY TODAY

The solid, rugged, high payload equatorial head breaks down into two components for easier transport and field setup. Because of this mount's size and weight, AP recommends that field assembly be done by two people. The RA axis and base assembly alone weighs just over 120 pounds, so most owners will not want to transport the mount on a regular basis, although this can certainly be done for special occasions.

Advanced Telescope Systems has developed a portable pier for use with the mount. The pier is extremely rigid, and folds up for transport. The mount can be powered with a commonly available heavy-duty, deep-cycle marine 12-volt battery. In the observatory, AP suggests a minimum 10-amp filtered, regulated power supply like its 15-volt, 10-amp system.

All electronics, including the GTOCP3 control box, motors, gearboxes or cables, can be easily removed for servicing. The mechanical design of the mount is extremely simple and straightforward, allowing easy adjustment by anyone – no need to have a mechanical engineering degree to service the mount.

AP designed the mount to allow cabling to be run through the axes shafts for tangle and clutter free operation. Cables from cameras, guiders, dew heaters, as well as the mount’s own servo drive cables, can all be run through the mount’s 4-inch shafts where they are out of the way and will never get caught or tangled during imaging sessions.

Ports have been included for the mount’s servo cables and custom cabling will be available for a variety of accessories.

The drive system uses two high-quality Swiss DC servo motors for each axis controlled by a microprocessor to an accuracy of 0.05 arc seconds per step. The dual motor

NEWPRODUCTS

STELLAR TECHNOLOGIES INTERNATIONAL Introduces CVF Series II system smoothes the drives even further by applying an averaged power curve to the drive system. The system can be accurately controlled over a speed range of 4800:1 which allows 0.25x sidereal for guiding to roughly 720x sidereal for 3 degrees per second maximum slew rate. The circuit draws well under an amp when tracking, 3 to 5 amps with both axes slewing, and requires only 12 volts to operate (15 volts is recommended).

The pier adapter for the 3600GTO has been integrated into the mount’s design and incorporates the design principles of the Precision Adjust Rotating Pier Adapters and, in an innovative twist, puts the Super Heavy Duty Azimuth Adjuster under the back of the mount where it is both conveniently located for fine polar alignment and remains out of the way. Polar alignment is smooth and easy and the system locks down tight with no unintended movement.

The mount will track and guide well past the meridian in either direction if the object is located such that the telescope will clear the pier. This allows the user to set up the mount for a long series of exposures without stopping in the middle to flip sides.

One can start the telescope under the mount while pointing at an object in the eastern part of the sky and track it all the way deep into the western sky. This is very useful for long exposure H-alpha or in cases where a large number of individual exposures are needed for stacking. The full 360 degree rotation of both of the 3600GTO’s axes also allows this mounting to be placed onto an astrographic pier for complete freedom from movement restrictions.

The 3600GTO is easily aligned with a polar alignment scope to quickly zero in on the pole for most non-critical observing or to get close before tweaking for imaging. AP’s built-in software routine allows polar alignment in the daytime for solar observing, viewing planets at twilight, and drift alignment on bright stars before nightfall.

For more information go to www.astrophysics.com.

The new CVF (Critical Visual Focuser) Series II from Stellar Technologies International affords 35mm format photographers a fast, easy, and economical way to attain critical daytime and nighttime visual focusing without guesswork.

While their CFV Series IV “Stiletto” knife-edge focuser is excellent for deep-sky imaging, it is restricted to night use when a pinpoint source of light is available as a target. On the other hand, focusing in daylight through a scope has largely been haphazard since no equivalent device was developed. Now photographers pursuing both day and night photography have an effective alternative.

The CFV Series II replaces the 35mm film or DSLR camera during critical focusing. This simple swap-in, swap-out process takes only seconds and guarantees perfect focus every time. This precision calibrated device projects a significantly magnified portion of the actual image to be recorded onto a high-resolution patterned focusing screen. Once the image is focused on the screen, the CVF is removed and replaced with the camera to take the actual picture using manual settings.

In a nutshell, the existing view screen

in a camera, whether DSLR or film, does not provide enough magnification and contrast for the eye to obtain perfect resolution during focusing. The eye compensates for an out-of-focus image automatically by up to 3%. Consequently, while focus may appear to be perfect to the eye, it is not at the exact focal plane expected by the film or chip in the camera. The result is a blurry image lacking definition.

By providing enhanced contrast via the CVF view screen, at high magnification, the CVF radically reduces the error to approximately 0.2 %. And, unlike traditional focusing screens and LCD view screens, the CVF completely eliminates interference from extraneous lighting, guaranteeing perfect focus even in extremely bright outdoor settings.

The CVF Series II is specifically designed to overcome difficulties of focusing 35-mm film or DSLR cameras, with models available for all 35-mm digital and film cameras, including Canon EOS, Nikon, Pentax, Olympus, Minolta, Sony, and others. Whether digital or film, you will find the CVF a valuable tool in your quest for perfect imaging.

For more information go to www.stellar-international.com.

APM refractors/Intes Micro Makustovs/Giro mounts

www.tetontelescope.com Astronomy TECHNOLOGY TODAY

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NEWPRODUCTS

KHAN SCOPE CENTRE Sky-Watcher EQ3 SynScan Go-To Mount and iOptron SmartStar Alt-Az Mount

Parabolic & Spherical optics Elliptical Diagonal Flats Complete interferometric data 27 years (full-time) experience

www.ostahowskioptics.com fineoptics@dishmail.net 951-763-5959

Astro Sky Telescopes & Piers

Precision Truss Dobsonian Telescopes and Piers Built by James Grigar

CATSEYE™ Collimation!

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www.astrosky.homestead.com/Astrosky.html

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Astronomy TECHNOLOGY TODAY

Khan Scope Centre has announced the immediate availability of the affordable Sky-Watcher EQ3 SynScan Go-To mount. The EQ3 SynScan is the perfect instrument for novice visual observers who want to enjoy astronomy with minimal setup time or knowledge of the night sky.

The EQ3 SynScan features positioning accuracy to 1 arc minute, accuracy enhanced by software collimation error (mount mechanical error) compensation, stepper motors with 1.8 degree step angle and 64 micro steps driven, slewing speed up to 3.4 deg/sec (800X), guiding speed selectable from 0.25X, 0.50X, 0.75X, or 1X, object database containing complete Messier, NGC, and IC catalogues, periodic error correction, premium PC interface: ASCOM and Nexstar-5i compatible protocol and command set, and upgradeable hand control via internet download.

Also available from Kahn Scope Centre is the new iOptron SmartStar Computerized Alt-Az Mount. Priced at a mere $266.00 CDN, the SmartStar-E, also known as The Cube,

offers the convenience of accurate go-to in a compact alt-az configuration that will carry a payload of up to 11 pounds.

The Cube features a stable tripod constructed of 1-inch stainless steel tube, 12volt DC servo motor drives, 5 speed dual axis slewing, a 5,000 object database, and the convenience of dovetail telescope attachment.

Kahn Scope Centre is offering The Cube at a remarkable discount for a limited time only – so hurry!

For more information go to www.khanscope.com.

NEWPRODUCTS

KENDRICK ASTRO INSTRUMENTS Offers New FireFly Heaters and Upgraded Premier Power Controller Kendrick Astro Instruments has expanded its dew control offerings with its new affordable line of FireFly Heaters and software upgrades to its proven digital Premier Power Controller.

Kendrick’s new FireFly heaters are designed for the astronomer who requires a dew prevention system that is both economical in price and power.

Having lower power requirements than Kendrick’s Premier heater line, these heaters will extend the life of batteries between charges. Using a different heater technology, but operating under the same principle as the Premier line of heaters, these heaters will mildly disperse heat into optics without compromising the figure of telescope or camera optics.

Through Kendrick’s unique manufacturing process, the FireFly heaters direct their heat into optics instead of losing it into the atmosphere. These heaters are very effective in directing most of the heat into the optics, which is important if dew is to be prevented.

Kendrick recommends, as a minimum, that a 12-amp hour rechargeable battery be used with this system.

For those wanting to use household current, Kendrick offers a 120-volt converter that puts out 12 volts DC at 4.5 amps. They also have a converter that is rated at 10 amps output and is

recommended for larger power requirements.

The Premier Power Controller is an advanced controller that offers a platform for centralized power management of telescope accessories and dew prevention heaters, and that is completely RFI (radio frequency interference) free.

The controller offers the advantage of powering and controlling various devices, accessories and heaters from one central device. Accessories such as Dob cooling fans, digital setting circles, illuminated eyepieces, telescope motor drives, secondary mirror heaters, motorized focusers, and more can be powered from the controller.

The controller’s many features include built in low voltage cut-off, LED brightness control, temperature/humidity sensing and control, a choice of Fahrenheit or Celsius operation, 6 outputs, and numerical keypad entry of operating parameters for control of settings. It also offers sensor readouts to

show ambient air temperature, optic temperature, dew point temperature, humidity in percentages, and battery voltage. It comes with a brushed stainless steel case with an optional brushed stainless steel cradle that connects to a tripod or Dob. Kendrick’s recently upgraded software enhances the controller’s ability to be programmed and monitored remotely from a PC. The software has an intuitive user interface that makes it easy to program and monitor the controller. The software will create a log file that can be imported into a spreadsheet program, which is useful should users have any reason or need to determine the operational functionality of the controller or heaters.

For more information go to www.kendrickastro.com.

Astronomy TECHNOLOGY TODAY

25

The FAR-Sight Binocular Mounting System

By Allan Keller

I admit that I am addicted to binoculars. Using both eyes to explore the night sky started with a pair of Sears 7x35-mm binoculars that my father gave to me as a birthday present when I was child - I still have that pair. I have since bought and sold more than 30 different binoculars over the years and still own about eight different sets.

The creation of the FAR-Sight Mounting System was born of my frustration with existing binocular mounts. I had several issues with them. Most that I had tried were neither sturdy nor of high quality. Generally, they were made of plastic and using a heavy binocular with these meant a long wait for vibrations to dampen out. It also meant avoiding touching the binoculars while viewing or the waiting game would start all over again. One key feature I wanted in my ideal binocular mount was a place to attach a red dot finder. This would aid in finding objects when using high power binoculars and at star parties would make it much easier to show other observers where an object was located in the sky. I also wanted to have the ability to easily change binoculars in the dark while using a single tripod or parallelogram mount.

26 Astronomy TECHNOLOGY TODAY

And so I set to the task of designing a bracket to overcome these problems and to add the features from my wish list – of course, it also had to look good. FAR-Sight is the result.

The FAR-Sight bracket is fabricated from laser cut stainless steel. I have tested it with binoculars up to 25x100mm with great success, although my favorite binoculars for use on the FAR-Sight are the Fujinon 16x70 FMT-SX. With most binocular mounts, great care must be taken to avoid cross threading the binoculars’ mounting hole, especially in the dark. To overcome this issue, I designed a mounting screw and keyway attachment system. The keyway is located on the stainless steel bracket. The FAR-Sight Mounting Screw is installed finger tight in the threaded mounting hole located between the barrels of the binoculars. The majority of binoculars utilize a 1/4-inch x 20 TPI (Threads Per Inch) screw size for this hole.

Farpoint also makes versions of the mounting screw for non-standard binocular mounting holes found on some Barska models (1/4-inch x 28 TPI) and the Nikon Astrolux (Metric M6 x .5). A small set screw

is located on the mounting screw to keep it from coming loose. After attaching the mounting screw onto the binocular, the mounting screw is inserted into the keyway on the bracket and pressed down into the slot. There is a spring mechanism built into the mounting screw that clenches the mounting stud onto the bracket. A safety catch on the bracket is then swung down to help prevent accidental lifting of the mounting screw in the keyway. As installed, the mounting screw permits rotation to accommodate changes in the interpupillary distance between the eyepieces.

Finding objects in the sky with high power binoculars can be troublesome – high power binoculars have a small field of view.

I wanted an easy way to target my binoculars in the night sky and decided that a red dot finder would work well. Zero power, red dot finders are light weight, inexpensive and easy to mount. These finders were first designed to be used with BB guns and firearms. The two most popular methods of mounting them are on either a standard dovetail slide or a Weaver mounting system.

The Weaver mount is the wider of the two.

I designed a series of shims on the top of the

FAR-Sight to accommodate most of these two red dot finder designs. The Celestron SkyScout may be used as a finder on the latest model of the FAR-Sight in some binocular and tripod or parallelogram configurations using an optional SkyScout Mounting Screw kit that is available from Farpoint. The SkyScout is very sensitive to magnetic fields, so follow the SkyScout instructions for best results.

The FAR-Sight is designed to work with most camera tripods or parallelogram mounts. Most tripods and many parallelogram mounts have a mounting plate with 1/4-inch x 20 TPI screw that will attach to the nut insert on the bottom of the FAR-Sight. Four holes are positioned 90 degrees apart around the nut insert on the base of the FARSight and can be used with the alignment pin found on many tripod camera plates to help prevent rotation of the mount.

For those with a Bogen 3030 style tripod head, the FAR-Sight does not need the camera plate. Instead it fits directly onto the camera plate hole on the tripod head and uses the cam lever for

attachment.

For use on a parallelogram mount, the FAR-Sight has finger and thumb platforms to assist in attaching binoculars.

This is necessary as the arms on parallelogram mounts float. Thumbs are used on the small platform halfway up the FAR-Sight for attachment. The wide area at the top of the FAR-Sight forms a platform for the fingers to assist in removal of the binoculars. Care must be taken when attaching or removing binoculars from parallelogram mounts due to the lift provided by their counterbalance systems.

Some older parallelogram mounts and tripods require a mounting screw that extends down from the FAR-Sight for attachment. An optional screw is available from Farpoint that is placed into the nut insert on the base of the FAR-Sight to provide this attachment.

If the FAR-Sight frees you from the frustration of using traditional mounts and helps you enjoy the beauty of the night sky with your binoculars, then it has accomplished its mission.

The FAR-Sight and its accessories are available from Farpoint Astronomical Research and from select dealers around the world. See www.FarpointAstro.com for more information.

Astronomy TECHNOLOGY TODAY

27

The Making Of The

Sierra Stars Observatory

By Rich Williams

I’m writing this article in the control room of the Sierra Stars Observatory (SSO).

In the background I hear the dome moving and watch image after image appearing on a monitor automatically without me having to do anything but write. It’s still a marvel to me and gives me great joy to see it in action. This is the story of how astronomy profoundly changed my life and how the Sierra Stars Observatory came to be.

The Inception of the First Torus Robotic Telescope It all started back in late 1995 when I was working in the Systems Division of Microsoft in Redmond, Washington. The Internet was still in its infancy and I started reading about what people were doing with the new CCD cameras attached to telescopes. It was revolutionary and I could see immediately that it would open up all kinds of opportunities for astronomers – especially amateur astronomers – to do imaging and get high-quality quantitative scientific data ten to a hundred times more efficiently than the conventional photographic techniques used at the time. Amateur astronomers were then taking images using home-built CCD cameras on relatively small telescopes that rivaled the photographic images taken with telescopes meters in diameter and new startup companies like SBIG were beginning to produce commercially available cameras. I could envision the future and I was hooked.

Early in 1996 I conceived an idea to build an automated observatory to use a CCD camera on a moderately large size (for the time) telescope that would be able to take images throughout the night automatically. I wanted the telescope, camera, and enclosure to integrate together to take scheduled images, save them to a hard drive, and then allow me to work with the resulting data the following day. Searching the Internet (pretty rudimentary back then) and resources such as Sky & Telescope and Astronomy magazines, I researched and contacted everyone I could find who was making telescopes, CCD cameras, and other equipment that I could use to develop the system I wanted.

The state of technology for what I wanted was barely developing back then. There was nothing even remotely “off the shelf” available at the time. After a few months of this effort I eventually contacted James Mulherin who was operating a small shop making high-quality optics in Iowa City, Iowa. During our phone conversations he told me about a couple of projects he and his bother, Tony, had worked on. They designed and fabricated 0.5-meter and 0.6-meter custom Cassegrain telescopes for customers in Arizona and Washington State. I was impressed with James’ knowledge and frankness about what he and Tony had done and could possibly do.

He was very open to my ideas and willing to tackle the development and he was very excited about the opportunity to do something

innovative and groundbreaking. This was the start of a long-lasting friendship and business relationship.

James is a very good listener and we spent a couple of weeks going back and forth about what I wanted to achieve and how we could go about meeting those goals. Fortunately, James has an open mind and was also willing to take an innovative approach to designing my system without falling back on the “conventional wisdom” of the day. During this process James presented some of his ideas based on his and his brother Tony’s experience designing and building their first few researchquality telescopes. One of their ideas, key to later success, was to design my telescope mount around a friction drive system.

Available drive systems produced for similarsized telescopes to date were based on wormgear systems. I gave the go-ahead for this idea.

They also had an interesting idea for a motorized secondary mirror focusing mechanism that made sense as well. So we settled on making a 16-inch f/10 Classical Cassegrain telescope based on these and other ideas.

After deciding on our hardware and electronic design we next had to decide on what software control system to use to control the telescope. I investigated what telescope control software was available (very few) at that time. I decided on Dave Harvey’s COMSOFT software which was an MS-DOS based control system using stepper motors. My first CCD camera was a prototype developed by a Astronomy TECHNOLOGY TODAY

29

SIERRA STARS OBSERVATORY

M 27

NGC 4565

NGC 891

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Astronomy TECHNOLOGY TODAY

SIERRA STARS OBSERVATORY

NGC 7635

NGC 7814

Astronomy TECHNOLOGY TODAY

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SIERRA STARS OBSERVATORY ware combination we were using just could not perform as I wanted.

SSO 24-inch Cassegrain Telescope.

friend at Microsoft. It was thermoelectrically cooled and we ran the camera on a separate computer running Windows. The software was fairly rudimentary, but worked well.

However, the focusing of the camera was done manually, which turned out to be much more of a hassle than I realized at the time.

I built a roll-off roof observatory on my property in Buckley, Washington. Now I only had to wait until the telescope shipped. The telescope arrived in a large wooden crate and Tony Mulherin flew in from Iowa to help with the installation. We rented a crane and my father-in-law, Berry Fox, operated the

crane and we installed the telescope onto a very substantial concrete pier in the telescope room. The first results using this new system were very promising. I did as much observing as possible considering the notoriously cloudy skies in Western Washington State. However, after using the system for a few months, I started to see some shortcomings with it. The control system was MS-DOS based and I wanted a more graphical interface for the system than COMSOFT offered. Also, and even more important, the tracking and pointing accuracy and precision were not as good as I expected. The stepper motors and the soft-

Making a Better Mouse Trap During this time James and Tony were helping develop a system for the Iowa Robotic Observatory (IRO) under an NSF program established by Dr. Robert Mutel at the University of Iowa. Along with Elwood Downey, they created the 20inch system for the IRO. After many back and forth conversations, we decided to retrofit my Torus Observatory with the OCAAS software developed by Elwood Downey for the IRO and to use servo motors instead of stepper motors. A final and very important change was to install optical encoders to close the feedback loop for tracking and pointing. Before then we used an open-loop system based on motor counts to control tracking and pointing.

Without going into more technical detail, these were some of the most important basic developments to creating what is today the current OMI advanced telescope system.

The new retrofitted system worked much better and OCAAS (later extended and renamed Talon by Torus Technologies) was a huge improvement over the previous control system. OCAAS included Camera, a powerful CCD camera control software program that also has some great built-in tools for doing precision photometry and astrometry work.

My next step was to buy a state-of-the-art CCD camera. I bought an Apogee AP7 with a 512x512 SITe back-illuminated chip with about 85-percent quantum efficiency. I then had one of the most advanced automated telescopes of its size in the world at that time.

A Major Career Change I was impressed with what I was capable of doing with the Torus Observatory.

Although we experienced other problems

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Astronomy TECHNOLOGY TODAY

SIERRA STARS OBSERVATORY and find potential customers. Between 1997 and 2003 I traveled the world presenting papers at various professional astronomy meetings including: four UN/ESA Workshops on Basic Space Science (Honduras, Jordan, France, and Mauritius), two meetings in Italy (one was the meeting that established the Torino scale for Earththreatening asteroids), and an International Astronomical Union colloquium on SmallTelescope Astronomy on Global Scales (IAU Colloquium 183) in Taiwan.

The first time I gave a talk about my paper in front of a group of professional astronomers in Tegucigalpa, Honduras, I was very apprehensive (scared is probably a more appropriate description). I was addressing a group of a couple hundred professional astronomers from around the world and I was one of the few non-Ph.D. astronomers at the meeting. It turned out that they were very interested in what I had to say about telescope technology and I met a Japanese astronomer who contracted with Torus to design and deliver a 0.5-meter and a

Unprocessed 14 Second Single Frame - Tom Osypowski 24" SpicaEyes on Dual Axis EQ Platform

while I used the observatory, we fixed those problems and developed a robust system. I could see that this was a breakthrough development and that the system and concept were potentially marketable. I talked with James about forming a company to develop, market, and sell robotic telescope systems based on our design. James and Tony were excited about the idea. I invested some of my Microsoft money and, with a few other investors, we formed Torus Technologies. One of my biggest personal decisions was to quit my job at Microsoft and start working full time for Torus. I talked with my wife, Kathy Fox-Williams, about this potential huge change in our lives and she was very supportive. In February of 1997 I left Microsoft and became the Vice President of Marketing and Product Development for Torus.

I decided to focus my marketing effort initially on the professional astronomy market, figuring that this was the target market for our telescopes. I researched on-line to find out what astronomy conferences and meetings were coming up where we could tell our story

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SIERRA STARS OBSERVATORY Canary Islands, South Africa, Canada, India, and several locations around the US. Moving to a Place with Clear Skies Western Washington State is one of the most beautiful places on earth.

Unfortunately it is also one of the cloudiest regions of the United States. During my first three years of operating the Torus Observatory in View of the Back-Plane of the SSO Telescope.

Buckley, Washington, my 1.0-meter telescope for a very advanced wideobservatory logs show that in the best year I field system intended to discover and monitor was able to use about 60 nights (out of a posnear earth objects (NEOs) and space debris sible 365 nights) during the year for serious for the Japan Space Forum. In subsequent observations. Also the observatory was located meetings over the years I landed significant at about 750 feet above sea level and the relacontracts for other telescopes for projects in tive humidity was normally high (as you Spain (4), Taiwan (4), Columbia, Virgin would expect for such a location) and excesIslands, Greece, Hong Kong, Korea (2), sive dewing was a often a problem. Basically

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Western Washington is not a great place to operate a “serious” observatory.

Kathy and I talked and we decided that we would move to a place where we would be able to have good observing conditions, have a good place to raise our children, and be able to do the things we like to do. We considered southern Arizona and New Mexico for the dark skies, but the trade off for our children (the remoteness) and our desire to still be near skiing (we love to ski and snowboard) were a negative. We finally settled on the Lake Tahoe area as giving us the best of what we wanted.

We found a great piece of land in Alpine County, California, two miles over the Nevada border in the Carson Valley. We bought 15 acres of land next to the West Fork of the Carson River and settled in, building a house and an observatory. Before we left Washington State, I sold my telescope to the Centro de Astrobiologia as part of a three telescope deal with Torus Technologies. Then we packed up and moved.

In 2003 Torus Technologies restructured to form Optical Mechanics, Inc., and as part of the restructuring I no longer worked directly for the company, although I continued on as the Chairman of the Board of Directors and as a partner in OMI. We struggled to reevaluate and redefine what OMI’s corporate mission should be and decided to focus our resources on the optics end of our business.

Even so, we continued to refine and sell telescopes. However, these changes in focus resulted in a long wait (for me) until we could produce the telescope I wanted for our new observatory. Finally, in September of 2006, my new 24-inch OMI telescope was delivered to our ranch in Alpine County. It was well worth the wait. In the intervening years we developed many refinements and I ended up with a far better telescope than I would have received had I gotten it sooner. This was the start of the Sierra Stars Observatory.

Making the Sierra Stars Observatory Vision Come to Reality I’ve been promoting the idea of creating a network of advanced robotic observatories

SIERRA STARS OBSERVATORY for over a decade. Although I talked with several groups over the years about making this a reality, the ideas never came to fruition. In the meantime, some people developed systems and are successfully implementing these ideas.

That is not surprising to me and only proves that what I envisioned was viable and made sense. Commercial software and hardware companies are producing and selling products to support automated telescope systems and numerous ones are operating around the world as I write this. I am very happy to see this development. However, there are opportunities to take these systems much farther.

My plan for the Sierra Stars Observatory was to create the foundation for a professional observatory network based on serious research-grade telescopes and instrumentation. The core components, the OMI robotic telescope and Talon observatory control software, were already in place. What I wanted to do now was create a successful enterprise offering high-quality imaging data through an innovative business plan. During my experiences over the years visiting with professional

and serious amateur astronomers many told me that they were very open to the idea of buying imaging time on a remote system that would provide high-quality data, especially on telescopes 0.5-meters and larger in diameter.

A New Approach The few remote robotic telescope Imaging Instruments mounted on the SSO Telescope - includes enterprises in existence FLI Proline 09000 camera (the primary imaging camera), the FLI today are primarily CW4-5 filter wheel with 50mm C (clear), B, V, R, and I JohnsonCousins photometric filters, an AstroDon MMOG off-axis guider, based on accessing and and an SBIG 402ME camera mounted on the off-axis guider for controlling the tele- autoguiding. scopes directly over ficient if you only want to get images of spethe Internet. This can be an interesting and cific objects at specific times and download rewarding experience, giving you the feeling the resulting data. Using the Sierra Stars of actually operating the telescope yourself.

Observatory system, you select objects from However, it can also be cumbersome and inef-

Astronomy TECHNOLOGY TODAY

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SIERRA STARS OBSERVATORY dozens of catalogs online (there are hundreds of thousands of objects to choose from), create a job to run, and then download your images after they are taken.

Using an easy-to-use form on our website, you select the exposure times you want for each available filter. Also you are not restricted to only selecting an object from our vast database. You can alternately choose View of primary baffle of the SSO Telescope. It is perfectly your own coordinates matched for the optics and specific camera. Even during a full (RA and DEC) and even moon there are no discernable reflections. specific time for an area enough in the sky during that time of year to in the sky to image. This is a great feature for be imaged reasonably high. You also need to doing exploratory work or imaging objects choose objects that are appropriate for the not in a current database.

Sierra Stars Observatory latitude. In other After you enter your observing request, words, you will need to do a little homework we include it, along with other scheduled before you schedule an object for imaging. requests, into our master scheduling program.

In the future we plan to add checks to This program then sorts all the observing our system to alert users if they select an inaprequests and creates a master schedule to autopropriate object for the time of year or our latmatically take each image at the optimal time itude and add on-line planning tools. Another for that evening. Each scheduled object is feature we presently offer is that your jobs run imaged as close to transit as possible. And the at the earliest possible date/time. If it is cloudy best thing is you only pay for the actual time or your job cannot run for some other reason, the shutter is open. You don’t have to pay for it will run at the next possible time. You can the time you are logged in, no matter how also cancel a job if you don’t want it to run much time you spend on our website. Of and/or schedule a job to run only at a specific course this requires that you know whether date and time. the object you choose will be positioned high

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SIERRA STARS OBSERVATORY

Declination axis friction drive.

Declination motor electronics package.

Many of our customers are professional astronomers and serious amateur astronomers who know exactly what they want to image for their projects. However, we also have astronomers using our system for astronomy course labs and even people who have little practical experience in using telescopes and are just curious. We are developing new tools and online content to help these users as well. You can find the most up to date information about using the Sierra Stars Observatory and our latest developments on our website (www.sierrastars.com).

Not Just Business The Sierra Stars Observatory is not simply about making money. Our business plan is somewhat unique. We have an ongoing grant program offering observing time and encourage anyone to submit a proposal for an SSO Grant. You can read the details of the requirements for submitting a Custom encoder and home switch retrofitted to the SSO Technical proposal to our grant program on our website. We also do outreach work Innovations 15-foot dome. with schools and other organizations.

The goal of our grant program is to foster innovation in the general astronomy community. You do NOT have to be a professional astronomer to qualify. We are open to anyone, regardless of your background, to submit a proposal. If it has merit, it will be seriously considered. Proposals to the Sierra Stars Observatory Grant Program are reviewed by our grant review board made up of four professional astronomers (you can read about their backgrounds at our website). Please do not let the fact that they are professional astronomers deter you from submitting a proposal. They primarily review proposals to insure that each makes sense and is doable, and they also act as mentors for the grantees. I sincerely hope that more people apply for these grants as the grant program is one of my favorite innovations for SSO. Ongoing Developments at Sierra Stars Observatory We are continually refining and extending the capabilities and features of the Sierra Stars Observatory. By the time you read this we will have

DomeFlat, SSO's unique solution for preparing flat fields. It is a canvas painted with a multi-spectrum reflective paint used for expensive large-format projection systems. Flat fields are taken by pointing the telescope at the panel using ambient light during twilight. This solution works well, even if skies are cloudy.

Astronomy TECHNOLOGY TODAY

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SIERRA STARS OBSERVATORY a new autoguiding system installed and operational. Up until now we have limited exposure times to 300 seconds (5 minutes) to ensure precise tracking. For most people this is more than sufficient for their needs, because you can stack as many images as needed to achieve a required signal to noise ratio (SNR) or image quality. Our CCD camera has the lowest noise of any camera I have ever used and stacking images adds very little noise.

And, the OMI drive system is the smoothest, most precise system on any commercial mount (remember, it’s a friction drive system without backlash or periodic errors). However, our new autoguiding system will ensure that you can have the highest precision tracking possible, regardless of how long an exposure you choose for individual images.

With the help of feedback from our customers, we are continually refining our web enterprise user interface and we will be adding more content to help customers more easily learn how to make the most of our system and enjoy a rewarding experience.

What You Can Achieve Using SSO We’ve only just started but some of our customers are already doing some cuttingedge projects pushing the capabilities of SSO. For example, one of our customers took images searching for the recently launched Dawn spacecraft. (Dawn is on the way to the asteroids Vesta and Ceres.). The first night he scheduled was cloudy and we ran his sequence the following night. By this time the spacecraft was nearly 600,000 miles away (more than twice as far as the moon). He imaged it in a 30-minute series of 2-minute exposures and submitted the data to the Minor Planet Center (MPC). He obtained astrometry data on a 20th magnitude moving object during a gibbous moon! That’s quite extraordinary. He now also routinely does photometry work using SSO for the AAVSO on 19th and 20th magnitude variable stars and hunts for nova in M33.

Most of our customers do less challenging work, but it is rewarding to get their positive feedback on using our system and to see

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their results (which, fortunately, most share with us). We are also working with professional astronomers using our system for introductory and advanced astrophysics courses.

Although we offer a very advanced and sophisticated observatory system, many people inexperienced in astronomy imaging are using our system as well. I enjoy helping and working with them to get the most out of the SSO system.

You Can’t Achieve Something Like this Alone!

Creating, operating, and extending the features of the Sierra Stars Observatory is quite a challenge. There are complex hardware, software, and web enterprise systems to maintain and develop. This is the most complex project I have ever worked on and it requires a lot of help from some very talented people. I am tremendously grateful to the people who have supported and helped me achieve my goal through the past several years.

I owe enormous thanks to Steve Ohmert.

Steve has been my friend for almost two

SIERRA STARS OBSERVATORY James Mulherin and the rest of the team at OMI have worked hard to develop the best telescope of its kind in the world and implemented many new features and improvements during its development. They continue helping with the project and are funding its new autoguiding system with the goal of implementing it on other OMI telescopes.

My great friend, David Gerdes, invested in Torus Technologies to help get things started, provided moral support, and always believed we would accomplish our goals, even during our greatest struggles.

Finally, none of this would have been possible without the total support and commitment from my wife, Kathy Fox-Williams. She’s an amazing person. Kathy developed (and continues to refine) the Sierra Stars Observatory web enterprise system.

SSO Equipment Description

This image of Comet Holmes represent 30 minute LRGB total exposures where the Luminance data comes from an Infrared filter. Exposure times were: I = 30 x 30 seconds B, V, R = 10 x 30 seconds each filter. Experimenting with the various filters I found that I could get the most detail using IR for the Luminance than a straight full spectrum Luminance. You can make out subtle detail in the image. I tracked on the comet and stacked the images on the nucleus therefore you can see some separation in the field stars. It seems that the comet is slowly turning from coming almost straight on (or away) from our point of view.

This was quite an amazing serendipitous event and a lot of fun to follow!

decades. He’s been an avid amateur astronomer since I’ve known him and is also one of the most talented software developers I’ve ever known. Steve, although heavily involved in startup software companies, worked with Torus, and later OMI (OK, I dragged him into it), to develop extensions

and fix bugs in OCAAS/Talon. Steve has also worked with me to create a new dome automation system for SSO, develop camera and filter wheel software, create other new software when needed, and has been a trusted advisor and always there to help when we run into trouble.

• 0.61-meter F/10 Classical Cassegrain telescope manufactured by Optical Mechanics • FLI ProLine CCD camera with a KAF09000 chip (3,056 x 3,056 12micron pixels) • FLI Filter wheel with Clear and B, V, R, and I filters The field of view of SSO, as equipped, is 20 x 20 arc minutes and the image scale binned 2 x 2 (our normal setting) is 0.82 arc seconds per pixel.

For a complete description of the SSO hardware, software, and web interface go visit the SSO web site www.sierrastars.com.

Astronomy TECHNOLOGY TODAY

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Test Driving the Sierra Stars Observatory

Like renting a Lamborghini while owning a Pinto (anybody remember Pinto’s?)

By David Snay

Sierra Stars Observatory (SSO) is a remote, fully automated observatory owned and operated by Rich and Kathleen Williams. The observatory is available for use by anyone that has Internet access. All you have to do is sign up, buy some time and schedule some imaging runs.

There are several high-end observatories advertising rental time on their equipment and have been for some time now. I have seen some amazing images produced on those systems, but have also been skeptical about the process for several reasons. The questions that I have always had about this approach are: • Would the system work as advertised and actually find the right object?

• Would the data collected be of good quality?

• Would that data be good enough to justify the expense?

• Would it be any fun if I weren’t out under the stars?

I come from an engineering background and understand the difficulties involved in automating any complex system; and a remote observatory certainly

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qualifies as a complex system. Consider that you have to control the dome, the telescope, the focuser, data acquisition, data storage and remote access to all that equipment and information, and you have one very long list of things that can go wrong. I’m sure the Williamses would be quick to add to this list as well.

I recently put the SSO system through its paces to find the answers to these questions and used my experience as a software designer/developer and hardware/software test engineer in an effort to perform as rigorous a test as possible. Read on to find out what I learned.

The Facilities Rich maintains and operates the observatory, which is located in Alpine County, California. The site is approximately 5,000 feet above sea level. This puts it well away from and high above any light pollution. The equipment that they make available for use is truly remarkable. There is a 0.61-meter telescope designed and built by Optical Mechanics, Inc., which features a Finger Lakes Instruments Proline camera with

Johnson-Cousins BVRI filters.

The facility is automated by Talon software that is truly state of the art. This software is capable of running the entire operation without operator intervention, including all mechanical operations as well as data acquisition and storage. It even makes sure the weather conditions are safe for the system to open up and start the night’s jobs before initiating and is capable of shutting the facility down if the conditions change. Pretty slick stuff!

The exact specifications of the equipment in place at the observatory are described in detail on the SSO website if you’re inclined to dig deeper than I’ve described here.

Using the System Using the system could not be simpler. Once you register as a user of SSO at www.sierrastars.com and purchase credits, you are able to access the system to schedule jobs and collect data. All you need to do is log in and schedule a job.

Then you are able to check the status of jobs you’ve scheduled. If they are complete, you can download the data as

many times as you like until it is removed from the system, which is currently scheduled for 3 weeks from the date of acquisition.

The data is verified for quality before being made available for download.

You’ll never risk downloading images that are out of focus, off target, or substandard in any way. I was amazed when I learned they went to this extreme to ensure the quality of the data. When I asked if this was standard operating procedure I was assured that it is and will continue to be the level of service delivered to all clients. I almost felt like I had insulted Rich when I asked that question; he is that committed to excellence.

Additionally, calibration files are generated every night and applied prior to posting for download, so you don’t have to deal with them, although you can elect to have the raw files and all calibration files made available for you to process. I suspect this might be beneficial if performing scientific tasks.

Web Interface Kathleen is responsible for the web interface software for the operation. She has done a fabulous job designing and implementing a very easy to navigate software package. There are a small number of sections, making it less likely you’ll

get lost in a long and twisting maze of links. There are only three groupings of links.

• Manage my Account This is where you purchase credits, schedule your jobs, and collect your data.

• Manage my Affiliates Affiliates are a totally cool concept that allows a primary user to purchase credits and allow others access to those credits. This is ideal for schools and other organizations such as astronomy clubs that have a central budget to make this facility available to all members. Affiliates can also purchase their own credits and they’ll remain available only to that affiliate.

• About SSO This is where you learn all about the facility and the features I’ve referenced above in much greater detail.

Most likely you’ll spend most of you’re time scheduling jobs and collecting data. Those tasks are very easy. Possibly the hardest part will be deciding what to shoot. The list of objects you can choose from is incredibly large. It includes every library I’ve ever heard of and a few I hadn’t. You can also select a set of coordinates if you choose. This could be partic-

ularly useful if you want to use the observatory for scientific research such as photometry and astrometry. I think this would be a tremendously accurate system for tracking asteroids and comets as well.

In my testing, I followed every link I could find and abused as much of the interface as I could. For the most part, the system either followed my instructions perfectly or told me I was brain dead.

Okay, it didn’t use those words, but it did tell me when I couldn’t do what I was trying to do. It also does a good job of telling you what you either did wrong or didn’t include for required information. This is a relatively new installation, so there were a few minor issues with the software, but Kathleen jumped on them and had replacement software online amazingly quickly. At last test, I was unable to find any problems with the interface. Well done, Kathleen!

I really can’t say enough about how impressed I am with the software Kathleen has put in place. She was very responsive to any and all questions I posed during my trial period and has plans for continued improvements. Remember, I spent 20+ years as a software developer and/or quality assurance engineer. I’m not easily impressed.

Astronomy TECHNOLOGY TODAY

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TEST DRIVING SSO

Image 1 is an example of M103 taken from my home location using my Meade 80-mm apochromatic refractor with a 6.3 focal reducer and a Meade DSI-Pro II imager.

This is riding on top of an 8-inch SCT that is guided by a Meade DSI-Pro. It represents 2 hours of total LRGB data as follows: L = 40', R= 20', G=30' and B=30' with 2' sub exposures. It also required a significant amount of time at the computer, processing the data to bring out detail and control things like noise and slight scale differences between the color channels.

Data Quality As I mentioned earlier, the data is verified for integrity prior to posting for

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download. That data is amazing! I found absolutely no defects in any of the frames I generated. I thought I had, but Rich

educated me about cosmic ray hits, which appear similar to hot pixels and can be treated as such. These are virtually unheard of at my murky sea level site, but at 5000 feet they are quite common.

Fortunately, they are easily dealt with.

Every star in every image is absolutely perfectly round. Nebula’s and galaxies have incredible depth, and detail is easy to pull out with minimal post processing.

The equipment provides a very high-res-

TEST DRIVING SSO

Image 2 is an example of M103 taken from the Sierra Stars Observatory. It represents a grand total 30' of LRGB data as follows: L = 12', R= 6', G=6' and B=6' also with 2' sub exposures. The first thing you’ll notice is that the image scale is quite a bit different between the two. The Sierra Stars Observatory really zooms in much closer than my setup. I hope that you’ll notice how much more round the stars are in Image 2.

Remember, Image 2 is one-fourth the exposure length of Image 1.

olution image in all channels.

Luminance, red, green and blue data channels are all beautifully crisp. This makes bringing out the colors of the object much easier and adding in luminance a breeze. Typically, I have to sharpen my luminance channel pretty aggressively to produce the sharpness I’m after.

The clear channel data provided by SSO requires no such sharpening.

Throughout this article I have used and will use the LRGB model for describing the data and images presented. Most astro-photographers are using Clear (for Luminance), Red, Green and Blue filters so the abbreviation of LRGB is common. However, the filters in place at the SSO are not Clear, Red, Green and Blue as we’re used to. They are a Johnson-Cousins Blue, Visual (green), Red, and Infrared filters which are a slightly narrower band than traditional RGB filters. Normal luminance data is

collected with no filter in place. Without getting into all the gory details of filters and the differences between the various types, suffice it to say that these filters are very high quality and will produce stunning images, which I’ll show shortly.

Planning The most important aspect of using this service is planning what to image on a given night. The SSO web page has a description of some recommendations for choosing targets to help ensure that they are optimally positioned for best results. What it basically comes down to

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TEST DRIVING SSO

Image 3 is M2 as taken using the SSO equipment. This is the result of only 18' of RGB data, each channel is 6' worth of 2' sub exposures. The detail in the core of the cluster is only possible because of the amazing optics and the sensitivity of the Fingerlakes camera in use. I don’t have a clue how much time it would take me to accomplish something like this with my home equipment.

Regarding choosing an appropriate target, suffice to say that if you have a planetarium software package, such as Starry Nights or Cartes du Ciel, you should have no trouble identifying targets well suited for any given time of year.

Once you’ve decided which objects are best suited for imaging on a given night, then you have to decide on the

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total exposure time and duration of each sub exposure. If your object requires only a small amount of time, single exposures of up to 3 minutes are perfectly achieved with the current implementation at SSO. If you need more than 3 minutes in each channel, then you need to stack them.

Rich is planning on adding guiding capability to the system to allow much longer exposures, but that was not in place at the time of this article. My experience with this setup has shown that significantly shorter total exposure time is required here than with my home equipment, as shown in my examples and the comparisons of Images 1 and 2 as well as Images 5 and 6.

I won’t go into all the details of best planning practices here, since Rich has already done a good job of that and is planning additional help online in the future. If you’re unsure of what you’ll need, you can use my experience as a starting point, or you could contact the folks at SSO and they’ll be able to get you started. There are also sample images in the SSO image gallery, which include exposure information for each image.

Time to Play For this article, I have produced four images using the SSO; an open cluster, a globular cluster, a nebula and a galaxy. I chose these four objects to show the versatility of the facility. Two of these images are contrasted against versions I made at home with my own equipment.

All exposures at SSO were unguided.

The image scale provided at this accuracy with no guiding is amazing. By the time you read this article, the SSO system will include an autoguiding capability. If I can produce images of this quality without guiding, the ability to guide this equipment makes me wonder, “Who needs Hubble?”

Another point to consider is the fact that the images I make with my home equipment can only be printed at about 4 inches by 5 inches before they start to break down. Image 6 can easily be printed as large as 8 inches by 10 inches, and probably much larger, with no loss of detail.

Conclusions I spent a little more than a month

TEST DRIVING SSO

Image 4 is M27 with the SSO equipment as well. This is the only one of the sample images where the filtration used at the SSO is apparent. The Visual (V) tends to produce a slightly more green cast to some objects.

When processing the image I first tried to make it look more like what I’d produced at home or have seen on the web. After a while I contacted Rich (the man has saintly patience) and learned about the difference in the filters. At that point I fell back on my artist’s training and made it my own.

Something I think we could all do more of.

Anyway, here it is.

accessing the observatory, both collecting data for imaging and putting the web interface through its paces. After a month of using and evaluating the Sierra Stars Observatory’s services and producing the images shown in this article it’s time for me to decide, “Is it worth it?” I say, "yes" for several reasons.

The location of the observatory is away from and above city lights and other light pollution. This obviously increases the quality of the data gathered.

It certainly is far darker there than it is in my front yard.

Renting time on Rich and Kathleen’s equipment is like renting a Lamborghini while owning a Pinto (anybody remember Pinto’s?). I can’t imagine too many of us have the means or the determination required to build a facility that remotely approaches what Rich and Kathleen have constructed. Even if I could, I’m pretty sure I’d much rather have Rich dealing with the maintenance of such a beast.

I worry about my equipment when I leave it set up overnight in my front yard. Can you imagine the stress a remote facility of this magnitude would cause me?

Going into this project, I was thinking that it would be hard for me to write a positive review. After all, I can take my equipment to the mountains of New Hampshire and Vermont or the darkness of Acadia National Park in Maine any

time I want. I’ve done just that on several occasions. I also attend a 10-day star party in the western part of

Massachusetts every year. Those trips are great fun, but I rarely come away with more than one or two high quality

Astronomy TECHNOLOGY TODAY

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TEST DRIVING SSO

Image 5 (top left) is another comparison of images made using my equipment vs. the Sierra Stars Observatory equipment. Both are M33. Image 5 was made using the same setup as my M103 image and Image 6 (bottom left) was made using the SSO equipment. Again the scale is different, but the truly impressive aspect of this comparison is that Image 5 represents 3.25 hours of data while Image 6 again is only 30 minutes of data.

images. Weather and pilot error usually conspire to reduce the useful nights to a minimum. Weather is not an issue when using SSO. If the weather is uncooperative, the dome stays shut and your job is run on the next clear night. Therefore, I usually end up spending more in travel and lodging per image than I would renting time a Sierra Stars Observatory. I camp on these trips, so the lodging is not five stars, nor expensive by any means.

Using SSO allows me to sleep in the comfort of my own bed and the company of my family.

The last concern I had going into this was the question of whether remote imaging using the SSO equipment would be any fun, despite not being out under the stars. What I found, to my surprise, is that the anticipation of downloading the data from SSO is much like that of Christmas Eve. I awoke in the morning and logged on before the sun was up to see if my job was done. I forgot that I’m on the East Coast and California isn’t. Now I had to wait all morning for Rich to analyze the data and post it for me and all the other users of the system. I just about drove my poor wife and kids out of their minds until my daughters suggested, strongly, I get out of the house. I’m one of those husbands/fathers who derives great pleasure from making his family wonder if he’s lost his marbles, so that was an added bonus.

Sierra Stars Observatory is not the

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Astronomy TECHNOLOGY TODAY

TEST DRIVING SSO only facility of it’s kind. I’ve explored the others from time to time, yet I remained unconvinced that remote imaging made sense. Until now. I think the glorious equipment and setting, combined with wonderful interactions with both Rich and Kathleen, is what made the difference for me. If you live in a location with extremely dark skies, have an observatory of your own and it is filled with supremely high-end equipment, then SSO might not be for you. However, I can think of a long list of astro-photographers who would be well served by trying SSO. If you’re thinking of trying your hand at imaging but aren’t sure about making the investment in relatively pricey equipment, SSO would be an easy and affordable way to experiment. Maybe you’ve got some equipment, but your skies have deteriorated to the point where it’s not fun anymore. SSO has some mighty dark skies. Or perhaps you’ve got a group of people who want to work on astro-pho-

tography together. Why not pool your resources and play on Rich’s equipment and let him worry about keeping it running? There is also the growing number of us who no longer have the stamina to haul our gear out on any given night and stay out there babysitting it all night long. How about the folks who have to go to work in the morning and just don’t have the time to get out there on a Tuesday night when the moon is out of sight and the Helix Nebula is calling to

you? In addition, let’s not forget about colleges and astronomy clubs for whom SSO is an ideal tool for scientific research.

I’m sure the readers of this publication can come up with a multitude of other reasons why the SSO approach just makes sense.

I highly recommend trying out Sierra Stars Observatory. You will be very pleased with the experience and will end up with some amazing images in the bargain.

Astronomy TECHNOLOGY TODAY

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Thousand Oaks Nebula Filters NECESSITIES FOR VIEWING NEBULOUS OBJECTS IN ALL THEIR TRUE GLORY

By Erik Wilcox

Nebula filters are popular accessories, and for good reason. Because emission and planetary nebulae emit narrow and specific wavelengths of light, a filter can be designed to let that light pass through, while rejecting the majority of other wavelengths (such as that caused by light pollution, a full moon, etc.). I find that a narrowband filter and an OIII filter are necessities for viewing many nebulous objects in all their true glory.

I’ve owned and used many different brands and types of nebula filters, but Thousand Oaks is one brand I’d never tried prior to reviewing them for this article. Most of my testing and comparing for this writeup was done with my 16-inch f/4.5 Dob, as well as one night out with my 4.5-inch f/8 Dob. The 2-inch filters arrived in a solid shipping box and they were packed very nicely. Each filter comes in its own plastic container that “snaps” closed. A soft piece of foam protects the filter inside the container.

The plastic containers are similar to what I’ve seen other filters come in, but these can be a bit difficult to open. There are two “lips” that can be pried apart, but a good

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Astronomy TECHNOLOGY TODAY

deal of effort is required to get them open.

Not a big issue, of course, but perhaps worth mentioning. It is possible that over time, the containers would “loosen up,” and become easier to open. My biggest concern was that the containers might open abruptly and the filters “fly out” and land on the ground because of the force necessary to open them.

I was careful and, thankfully, that didn’t happen. This is possibly a positive thing though – I certainly wouldn’t be worried that the cases would accidentally open, allowing the filters to fall out and maybe that’s their main purpose.

Once I got the containers open, I was struck by how unique and nice these filters looked. The body of the filters is a bit thinner than I’m accustomed to seeing and I really like the look of the slim design. The lettering and finish is top notch and the coatings appear nice and smooth. According to Thousand Oaks, they apply their coatings in a different way from most companies.

This special process is called “Ion Beam Sputtering,” where the substrates are bombarded with high energy ions during the deposition under high vacuum. This process

is said to lead to a very dense coating that isn’t affected by humidity or other conditions, as the glass and coating material are compacted together to cause a strong bond.

The second side of the glass has an antireflection coating, and the clear optical glass itself has a flatness of lambda/4. Also, according to Thousand Oaks graphs, their filters have a higher transmission band that is centered more accurately than many other filter brands.

The threads on the filters looked to be very precisely machined, so I decided to try threading them onto some of my accessories. I've had difficulty threading many filters onto certain eyepieces, etc., as there doesn’t seem to be one uniform, “universal” thread that every manufacturer can agree on.

In addition, the threads on many less expensive filters aren’t always machined to a very high tolerance. I’ve owned several filters that only partially thread onto certain accessories and even getting them on at all is sometimes difficult. I often have to rotate the filters back and forth to get them on and to avoid cross-threading.

That wasn’t the case with the Thousand

Oaks filters. No matter what 2-inch accessory I used, they threaded on accurately and smoothly. I tried adapters, eyepieces, diagonals, and even my Paracorr – the filters threaded perfectly onto everything. This might seem trivial, but in my opinion, it’s very important. A filter with poorly machined threads could come loose and fall onto the ground (or worse, onto the optics) and damage the threads on whatever accessory it’s being used with. Also, if it’s crossthreaded and the filter’s glass isn’t aligned properly with the eyepiece, the performance could be compromised. I was impressed that none of this was a concern with the Thousand Oaks filters.

I got the filters out on several nights under a somewhat mediocre, suburban sky at my nearby “dark” site. The Milky Way is vaguely visible at this location and I estimate the overhead limiting magnitude to be between 5 and 5.5. A noticeable light dome exists along the Northern horizon and extends upward about 20 degrees, but the rest of the sky is relatively unaffected. Seeing

and transparency appeared to be above average on the nights I viewed from this site and the moon wasn’t out. In addition to the Thousand Oaks filters, I had my own 2inch, somewhat inexpensive, “ultra-blocking” “Brand-A” narrowband filter and a popular, “Brand-B” OIII filter that costs a bit more than the Thousand Oaks OIII. My first target was NGC 7662, the Blue Snowball Nebulae, as it was nearly at the zenith. This is a relatively bright planetary nebulae located in the constellation Andromeda. The best overall view seemed to be with the OIII filter and my 16-mm Nagler at 131x. The Thousand Oaks OIII made the background sky jet black and the object stood out nicely. Both OIII filters worked well and I couldn’t see a noticeable difference between the two brands on this object.

Next, I tried one of my favorite targets, the Veil Nebula (NGC 6960 and 6992).

While nearly invisible without a filter, the Thousand Oaks OIII made both sections stand out beautifully at 70x. Long, detailed

“strands” of nebulosity were visible and I spent a good deal of time viewing this incredible object. After going back and forth between both OIII filters, I noticed that through the Thousand Oaks OIII filter, the Veil “popped out” slightly better against the background sky than it did through the “Brand-B” OIII filter. This was a very subtle thing, but after a good deal of side by side comparison, I determined that it was a real observation.

On M57, the Ring Nebula in Lyra, I saw the first major visual difference between the different brands of filters. While using my 9-mm Nagler at 233x, I compared the Thousand Oaks Narrowband with my “Brand-A” narrowband. I was surprised to see that a good deal more detail was visible through the Thousand Oaks filter. With the “Brand-A” narrowband filter, the ring was “flattened” near the upper right hand corner at about 2 o’clock (as viewed through my Newtonian) and the outer edges of the whole nebula seemed to be a bit more “cut off.” With the Thousand Oaks narrowband

Astronomy TECHNOLOGY TODAY

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THOUSAND OAKS NEBULA FILTERS filter, the upper right hand corner of the ring was more visible and in studying the edges of the ring, they appeared more “natural” looking; as opposed to just suddenly “stopping,” the nebulosity “faded” more before giving way to the black background. Also, I could see slightly more nebulosity towards the central area of the ring. The difference in the edges and central area was a subtle thing, however, the “flattened” area left by my “Brand-A” narrowband filter was not. My wife verified that she could see this as well.

It was as if my “Brand-A” narrowband filter was cutting off too much of a certain wavelength compared to the Thousand Oaks Narrowband filter.

Intrigued by this development, I turned to a couple of other planetaries - M27, the Dumbbell Nebula in Vulpecula and its “cousin,” M76, the Little Dumbbell, in Perseus. While I preferred the views with an OIII filter overall, I still felt that the Thousand Oaks Narrowband showed a better and more detailed view than my “Brand A” narrowband on these objects. By this time Orion was up in the east, so I swung

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the scope over to M42. Again, the difference was fairly obvious, and even more so on this object. The Thousand Oaks Narrowband showed more nebulosity and more detail than my “Brand A” narrowband. It was becoming plain that the Thousand Oaks was superior to my own narrowband filter.

While pointed at M42, I inserted the Thousand Oaks OIII into the focuser. I often enjoy viewing M42 at high power with an OIII filter, as it shows a more “textured” view of the nebulosity than a narrowband filter does and the stark contrast against the background sky is an incredible effect. At 233x, the Thousand Oaks OIII filter provided a beautiful view, though Orion was still low enough that I could see some atmospheric effects at this magnification.

I also inserted the Thousand Oaks HBeta filter to see if I could see IC 434, the Horsehead Nebula. I could see something there, but the less than perfect skies hurt the views here. In addition, I didn’t have another H-Beta filter to compare the Thousand Oaks against. I was able to clearly see the outline of the California Nebula by holding

the filter up to my 50mm finderscope, so the filter was certainly doing its job.

Through the next few clear nights, I had similar results on a variety of objects and really enjoyed using the Thousand Oaks filters. These are truly premium nebula filters that delivered performance superior to the filters I compared them against. In addition, the machining and build quality is first rate and the prices of these filters are very competitive. Though they are a bit more expensive than the so-called “bargain” nebula filters, the Thousand Oaks narrowband filter in particular performed much, much better than my “Brand A” narrowband filter.

They are also priced a bit less than some other “premium” brands and, in this case, I felt that the Thousand Oaks OIII filter was slightly better visually than the more expensive “Brand B” OIII filter and noticeably better in terms of build quality and machining.

I wouldn’t hesitate to recommend the Thousand Oaks nebula filters and, given this experience with them, they’d likely be my first choice.

THOUSAND OAKS NEBULA FILTERS

NEBULA FILTERS LP-1 BROADBAND: For slight light polluted areas.

LP-2 NARROWBAND: For heavily light polluted areas.

LP-3 Oxygen III: For diffuse and planetary nebulae.

DESCRIPTION

SIZE

PRICE

PART #

SIZE

PRICE

PART #

Broadband

1.25"

89.00

LP-125

2"

179.00 LP-148

Narrowband

1.25"

89.00

LP-225

2"

179.00 LP-248

Oxygen III

1.25"

89.00

LP-325

2"

179.00 LP-348

H-Beta

1.25"

89.00

LP-425

2"

179.00 LP4-28

Minus Violet

1.25"

59.00

MV-25

2"

79.00 MV-48

Astronomy TECHNOLOGY TODAY

51

What is a REVOLUTION?

The revolutionaries can be seen here in this team photo.

Texas Astronomical Society of Dallas Hosts Advanced Alt-Az Telescope Workshop

By Max Corneau

Webster’s Dictionary defines a revolution as a sudden, complete or marked change in something. What magnitude of change in telescope design would constitute a revolution during this first decade of the 21st century?

On the last weekend in October, a group of nearly 30 scientists, engineers, industrialists, and amateur astronomers gathered for two days and nights in Dallas, Texas, to launch a revolution in telescope design. Hosted by the Texas Astronomical Society of Dallas (TAS), the event was billed as the “Advanced Alt-Az Telescope Workshop” (AATW).

Was this a “Vapor Ware” conference highlighted by self-promoting enthusiasts trying to make a name, a buck, or both? Or was this group gathered as a dedicated community of interest seeking to launch a true revolution in telescope design? Perhaps this topic is most appropriate for the Astronomy Technology Today Yahoo Group to discuss.

If you’re not the “reading type” I’ll cut to the chase: The bottom line results of the Advanced Alt-Az Telescope Workshop indicate that it is possible, by integrating a variety of advanced technology components, to construct a 20-inch Corrected Dall-Kirkham design telescope on an alt-az mount for

approximately $13,000 (unassembled).

Given the alt-az approach, the 20-inch design appears to be the smallest size that justifies this design. However, the alt-az approach scales upward in favor of the consumer, as many costs like encoders, motors, and bearings remain relatively fixed. Based on the workshop results, the bill of materials (BOM) is itemized in the table (right).

How the Workshop Came to Be The AATW was the brainchild of Russ Genet, Ph.D. Russ and I first met in 2003 and have remained friends since. After being elected as Vice President of TAS in September, I asked Russ to be my first guest speaker for the monthly general membership meeting program. My original request for an hour-long presentation on Russ’s work with small telescopes in science evolved into a 40minute presentation followed by a 20-minute panel discussion to our club on Friday night at the University of Texas at Dallas. Then on Saturday, at The Richardson Hotel, a group of 30 assembled all day to conduct a disciplined workshop.

After realizing that Russ was using the

Dallas invitation’s central location as a vehicle to launch his hoped-for revolution, the systems engineer in me surfaced and I questioned the “requirements” we were building this telescope to. Retrospectively, this was an extremely appropriate question, that was unfortunately, never answered. However the 20-inch Corrected Dall-Kirkham design telescope on an alt-az mount Finished Optics (primary, secondary, corrector) .......$5,000 2 Encoders...............................$1,400 2 Motors (parts, not assembled) ........$600 2 Bearings ...............................$1,000 Carbon Fiber Truss Poles................$700 Truss Pole Connectors ...................$400 Mirror Cell including back plate (parts only) ..............................$1,000 Spider and Secondary Holder (custom fabrication) ......................$400 Field de-rotator, OAG, focuser .......$1,500 Material for forks and other structures (not assembled).........................$1,000 Total Cost .......................$13,000 Astronomy TECHNOLOGY TODAY

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TAS ADVANCED ALT-AZ TELESCOPE WORKSHOP objective of the workshop, notwithstanding any specific science or user requirements, was to explore nine different areas: 1. Lightweight, affordable optics 2. Precision control systems and drives 3. Direct drive motors 4. Field de-rotation 5. Observatory automation and scheduling 6. Autoguiding 7. High natural frequency mechanical structures 8. Bearings for alt-az telescopes 9. Structural alternatives/Session Q&A wrap-up Friday Friday evening was billed as the “Kickoff ” event to this revolution.

Unfortunately (for my stress level), Russ Genet’s first flight from the central California coast was cancelled and his next flight was delayed. Before 5pm, we knew that it was mathematically impossible for Russ to make his speaking engagement. However, Dave Rowe, designer of the Corrected DallKirkham (CDK) telescope, became my new best friend and gave Russ’s presentation without missing a beat; many thanks to Dave Rowe for running with the ball.

Dave’s presentation addressed the limiting factors of equatorial mounts (size, weight, and cost) as they support larger aperture systems, then dealt with examples from major scientific, or “mountaintop” telescopes. The presentation transitioned nicely into the small telescope revolution, made possible primarily by fork-mounted Schmidt-Cassegrain Telescopes (SCT), pointing out that these are only upwardly scalable to a 14- to 16-inch design before the corrector plate becomes a limiting optical design factor. With the audience decisively engaged in the subject matter, Dave drilled into a potential convergence of the Dobsonian design and mountaintop alt-az systems. The convergence (and here’s the revolutionary part so pay attention) is facilitated by lightweight aerospace materials, active control systems, and brushless motors.

Preliminary telescope designs for our

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revolutionary telescope design considered the following systems and their pros and cons: The Hyperbolic Newtonian (HN) provides excellent wide-field optical performance and a convenient Newtonian focus, but requires an overcorrected primary. Another optical design, the Wynne-corrector plus parabolic mirror, provides an acceptable alternative to the HN in some situations, however is beset by a lack of back focus that seriously limits the variety of scientific instruments to be placed in the optical train. One additional negative for this design is the fact that the corrector is large, expensive and difficult to make. In a “saving the best for last” methodology, Dave showcased the Tertiary-focus Corrected Dall-Kirkham (CDK) large telescope design. The optics are less challenging to fabricate for this system relative to the Richie-Chrétien (RC) Cassegrain and provide the added, and very significant advantage of being easier to collimate than the RC and Newtonian telescopes.

Following the planned 40-minute discussion describing how the confluence of low-cost telescope control systems, affordable aerospace materials, and innovative optical designs enable a revolutionary new class lightweight, highly capable alt-az telescopes to emerge, we convened a panel discussion.

Panelists included Tom Smith of the Dark Ridge Observatory, Tom Krajci, Dave Rowe of Sierra Monolithics, and Dan Gray of Sidereal Technology.

As the moderator, I asked a pre-planned question to jump-start the panel discussion: “How would you design a 20- to 25-inch advanced alt-az telescope for TAS?” Here, the requirements question that I had posed earlier to Russ et al in a collaborative thread, came back to roost as the panelists returned the question in terms of questioning the requirements. Dan Gray replied that the cost depends on the goals the club has in mind for the telescope. Tom Krajci echoed this comment with a ‘what will it be used for’ point, while Tom Smith, recognizing our potential student affiliation with the University of Texas at Dallas, wisely suggested that we consider what students might be

able to use the telescope to accomplish. Dave Rowe wrapped up the panel by addressing the participatory aspect of an advanced alt-az design by suggesting that a one-meter triple truss CDK telescope could serve both visual and demanding scientific imaging given the following characteristics: • Effective focal length = 5930 mm (f/5.9) • Fully baffled over 55-mm image circle • Flat field • Geometric RMS spot diameter < 10 microns over full field • Extremely well corrected from 375 nm to 1000 nm • Eyepiece height less than 1.8 meters (70 inches) • Back focus > 200 mm • Spherical secondary is easy to collimate • Much less expensive than other Cass alternatives Ultimately, we settled on a “whiteboard derived SWAG” of around $20,000 for a 20inch CDK telescope that could serve equally well in both visual and imaging roles and provide easy visual eyepiece access and uncomplicated collimation. The panel was very helpful and stimulated the assembled group of 100 or so members and visitors to think more deeply about the possibility of our Society obtaining a telescope capable of providing exceptional visual observations as well as doing hard science.

Saturday With all scheduled presenters on station, except for Richard Kay, President of Impact Bearings, Inc., the workshop commenced its daylong effort at the Richardson Hotel. At the conclusion of the meeting, we dined at a newly discovered “astronomy restaurant,” most appropriately named, Luna de Noche, on some of the finest Tex-Mex faire available in the Dallas-Fort Worth Metroplex.

Dave Rowe’s initial presentation, titled “Lightweight Affordable Optics,” set both the stage and the bar relatively high for those who would follow. Much to the satisfaction

TAS ADVANCED ALT-AZ TELESCOPE WORKSHOP

Diffraction and Spot Diagram Simulations courtesy of PlaneWave Instruments Inc.

of my systems engineering “requirements approach” to doing things, Dave stated the requirements for his approach up front.

In order to be useful, the system must afford convenient access to instruments and eyepiece. This requirement can be achieved through a Newtonian focus or tertiary Cassegrain focus. The explosion of low-cost, large-format CCD chips and arrays dictate that the system provide excellent images over a large, flat field. Specifically, the instrument should be able to support 37-mm x 37-mm CCD formats across 400 nm to 850 nm of the spectrum. Most importantly for scientif-

ic applications, the system should provide for adequate back focus for imager, filters, offaxis guider (OAG), and deviator. Specifically, he adopted a baseline requirement of greater than 90-mm back focus. Finally, the three factors that can justify the moniker of revolutionary for such a system are that these requirements are to be met in an affordable, compact and lightweight, package that offers ghost free images. Right on Dave!

Rick Hedrick, formerly of Celestron, and most recently a 2006 co-founder of PlaneWave Instruments, Inc., provided an excellent embellishment on several concepts

addressed by Dave Rowe in his presentation on “Corrected Dall-Kirkham Telescopes.”

From Rick’s perspective, a primary driver for the CDK design is to support the 42-mm to 52-mm (diagonal) CCD chips with an affordable system. Primary drivers addressed

by Rick also included a large, flat, coma free field that must be less expensive than a traditional Ritchey-Chrétien design and easier to collimate.

Rick’s PlaneWave website articulates the advantages of the design extremely well (www.planewaveinstruments.com). In the graphic (left), the small squares in both simulations are 9x9 microns, about the size of a common SBIG science CCD pixel. In the diffraction simulation the star images on axis and off-axis are nearly identical. In the spot diagram 21-mm off-axis the spot size is an incredible 6 microns RMS diameter. This means stars across a 42-mm image circle are going to be pinpoints as small as the atmospheric seeing will allow.

Both of the simulations take into consideration a flat field, which is a more accurate representation of how the optics would perform on a flat CCD camera chip. For visual use some amount of field curvature would be allowed since the eye is able to compensate for a curved field. The diffraction simulation was calculated at 585 nm.

The spot diagram was calculated at 720, 585, and 430 nm. Many companies show spot diagrams in only one wavelength, but you cannot see the chromatic performance with only one wavelength.

Given the relative advantages of performance, cost, and ease of use articulated by both Dave Rowe and Rick Hedrick on the CDK design, the logical follow-up question asked by one of the workshop attendees was, “how scalable is this design?” The simple answer is that the low end of the CDK design is about 20 inches and it scales upward to about two meters. And, according to Rick, the cost will likely increase as the cube of the diameter.

Following Rick Hedrick’s presentation, the workshop took a decidedly esoteric and less practical, if only from an Earth-based Astronomy TECHNOLOGY TODAY

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TAS ADVANCED ALT-AZ TELESCOPE WORKSHOP perspective, turn. Dr. Peter Chen of the NASA Goddard Space Flight Center shared both his vision and daily challenges developing a telescope for use on the Moon in his presentation titled, “Carbon Fiber Mirrors.”

Peter is truly on the cutting edge, far ahead of programs and funding, forced to use tremendous ingenuity and creativity to make his dream of a telescope on the moon a reality. Peter’s major accomplishments include inventing a lunar telescope using ultra lightweight replica optics and high temperature superconductors for which a U.S. Patent was issued in April of 1993 and co-inventing new processes of making ultra-lightweight optical telescopes by composite replication for which several patents are currently pending.

Peter stated his objective to the workshop as wanting to develop telescopes to put on the Moon, which he immediately clarified, is a topic that only recently could be discussed in polite company. Dr. Chen’s thesis statement to the workshop was that carbon fiber composite laminates offer unlimited size whereas beryllium optical surfaces have only been made up to four meters. In his design, a simple laminate substrate stiffens and supports a pure resin optical surface. In this modality, Peter has built a 36-inch mirror that weighs only nine pounds.

Unfortunately, Dr. Chen’s early composite mirror designs encountered what NASA refers to as a “show-stopper” problem.

Given differential coefficients of thermal expansion (CTE) whereby the laminate = 0 and the resin = 60, when subjected to thermal cycling, the mirror underwent a host of unacceptable changes including buckling, wrinkling, and de-lamination. The undesirable characteristics were ultimately attributed to the differential CTES between laminate and substrate. This problem can be solved, according to Peter, by graduating the differential CTEs through additional layers, or by modifying the fiber resin using carbon nanotubes.

Nanotechnology expands the potential for Dr. Chen’s composite mirror technology.

Effects of wind loading on a terrestrially based composite mirror probably requires

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TAS ADVANCED ALT-AZ TELESCOPE WORKSHOP active mirror control. This apparent limiting factor actually drives a deeper design evolution. Already on the books, United States Patent 7064885 (http://www.freepatentsonline.com/7064885.html) describes a lightweight active mirror where the first layer has a front side and a backside. A second layer has a front side and a backside and the backside of the second layer faces the front side of the first layer. A reflective surface is on the front side of the second layer. The reflective surface is operable to reflect desired wavelengths of electromagnetic radiation. A plurality of electroactive actuator strips arranged between the first layer and the second layer are utilized to alter the curvature of the mirror. A plurality of stiffening elements interconnected with at least one of the first layer and the second layer are used to stiffen the mirror. A plurality of shape retaining elements attached to at least one of the first layer and the second layer are used to control the mirror and to bias the mirror in the desired position.

In his discussion, Dr. Chen addressed a revolutionary, embedded active mirror design whereby carbon nanotubes are laid up and aligned in the mirror such that they can be used as actuators when a voltage is applied to them. This design concept appears to evolve “smart” mirror technology to the level of “brilliant mirror technology.”

Dan Gray of Sidereal Technology, Inc., provided the next presentation titled “Precision Control Systems and Drives.”

Dan’s philosophy regarding precision telescope control is refreshingly straightforward: Step 1 – acquire the object; step 2 – stop the telescope. Dan’s presentation provided an excellent historical context of mechanical telescope control whose origins date back to the University of Wisconsin’s work with synchronous RA motors in the 1960s. Notably, Dan cited Russ Genet’s work in this domain, including the text, Real Time Control with Microcomputers by Russ Genet and Lou Boyd in 1982, and the first operational implementation at the Fairborn Observatory in 1983. Another one of Russ’s co-authored publications, Microcomputer Control of

Telescopes, this time with Mark Trueblood in 1983, remains a sought after publication today.

The presentation transitioned smoothly to a comparison between servo and stepper systems that described the wider dynamic range afforded by servos as well as greater angular accuracy while tracking. The downsides to stepper motors include mechanical wiring differences, magnetic hysterisis, and torque error. Advantages to servos include lower current consumption and greater torque per cubic inch. Dan’s presentation noted that small servos can control telescopes up to 41 inches. Additional advantages of servos is their tolerance to resonant frequency effects and providing continuously accurate step data. Servos, as opposed to stepper motors, will never miss a step and lose position information. Given the balance of advantages and technology, it is not surprising that the cost of a stepper system is less than a servo system. However, Gray indicated that his company has managed to converge the two price points. Finally on the topic of drive systems, Dan articulated the virtues of brushless D.C. motors versus brush-type D.C. motors. His assertion was that brushless motors are more efficient and require less maintenance, but are more expensive.

Again, the demands of tracking and pointing are determined by the telescope’s primary role. Photographic operations impose stiffer requirements for both cases.

Precision requirements in this case can be met by closed loop systems such as SiTech according to Dan. After describing significant considerations of sky and telescope system, Dan Gray introduced a software application developed by Dave Rowe called PointXP. This application accounts for telescope modeling in terms of hub, axis perpendicularity (Z1), cone, collimation error (Z2), forward/reverse and left/right axis imbalances and the sin and cosin of declination droop. Applying the best practices described, Gray stated his personal goal of precision in unguided tracking is 10 minutes with a 14-inch telescope and SBIG ST8

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Astronomy TECHNOLOGY TODAY

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TAS ADVANCED ALT-AZ TELESCOPE WORKSHOP camera. This particular use case establishes maximum drift of one arc second per ten minute period.

In another easy transition, Gray’s presentation turned to gears versus rollers and the pros and cons of each. Of course, gears offer no slippage. However, they will always induce backlash, windup error, non-periodic and periodic errors. On the other hand, rollers offer little or no backlash and periodic error, but slippage can be a huge problem according to Gray. To eliminate adverse roller characteristics, Gray offers two options: tick management, and closed loop high-resolution encoders. Gray asserts that using an inexpensive 10,000 tick encoder can effectively eliminate aforementioned adverse characteristics. The most common downside is encoder runout on this type of system.

Closing the feedback loop with high resolution encoders provides the main advantage of countering wind gusts.

After thoroughly examining many aspects of precision telescope control, Gray steered the workshop back to the comparison between equatorial versus alt-az platforms.

Echoing his predecessors, he extolled the stability and cost-effectiveness of alt-az mounts, while addressing the inherent problems associated with field rotation. Field de-rotation is necessary to support autoguiding, flat fielding (near field) and to a lesser extent cable management. Gray again admitted to one of his life goals, that of making an affordable alt-az telescope a better decision than a comparably sized equatorial. He believes strongly that the crossover price point lies at the 20inch range.

Gray made the case that all three major problems associated with alt-az field rotation are solvable through a variety of techniques.

In terms of guiding, there are four potential solutions: (1) don’t guide, (2) guide with a dual chip system such as SBIG, (3) use one or two off-axis guiders, or (4) use a guidescope that hands off the guide star to different pixels, which requires plate solves to find the exact radius and angle on the guide chip. Another guiding issue associated with alt-az systems is alt-az inputs versus RA/Dec

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inputs which are normally given in alt-az if controlling an alt-az scope. There are four solutions to this problem according to Gray: (1) re-calibrate often, (2) rewind the rotator, and (3) change firmware to guide in RA/Dec, or (4) use wireless guiding.

A ten-minute unguided image on an alt-as scope passing Gray offered near the zenith by Dan Gray several solutions to subsequent commands to recenter the priflat fielding: either eliminate system mary image at a user-defined interval. What vignetting or center the vignetting, model the user defines depends on a variety of facthe vignetting, or take flats at all angles and tors, including tracking performance, centerinterpolate using software. ing accuracy, and driver errors. A step Astronomy is, after all, a practitioner’s beyond non-traditional autoguiding employs undertaking. Dan Gray is a true practitioner tip-tilt systems such as the SBIG AO-8 and who established goals and decomposed them AO-L which can correct at rates up to 10Hz. into requirements. The ten-minute unguidThese systems, according to Krajci, work ed image (shown above) provided courtesy best on smaller apertures and can counter the of Dan is indeed worth a thousand words. effects of mild breezes.

Tom Krajci of the Astrokkolkhoz In a clever way to talk himself out of Observatory at 9,440’ in Cloudcroft, NM, doing an autoguding presentation, Krajci introduced the next session on offered an excellent primer on why we auto“Autoguiding” in Russian and would have guide and what must be done before we can continued on his linguistic excursion had the do away with autoguiding. Tom asserted that workshop attendees not requested English as autoguiding is used to counter the adverse the preferred language. Tom’s presentation effects of polar axis misalignment, periodic addressed the historical context of traditionand random drive errors, long term RA drive al autoguiding, followed by faster tip-tilt corrate drift, mount/telescope flexure, and rection methods, requirements that must be wind. In order to abandon autoguiding, we met to abandon autoguiding, and must use a very stiff system that incorporates optical/mechanical design considerations. As two high resolution encoders and that is one who has manually guided a massive 12accurately aligned and able to counter wind inch Clark refractor at the U.S. Naval gusts through a fast-reacting drive. It’s that Observatory, I can attest to the rigors of this simple and a most appropriate topic for the technique on the observer compared to using attendees at an advanced alt-az telescope my dual-chip SBIG camera or piggy-back workshop. autoguiding system.

Next on the agenda, Tom Smith, assistKraji’s approach to non-traditional ed by Tom Krajci, provided an excellent presautoguiding leverages the fact that software entation on “Observatory Automation and can be used to perform astrometric calculaScheduling.” Smith, now the Director of his tions on the main CCD image and issues

TAS ADVANCED ALT-AZ TELESCOPE WORKSHOP own Dark Ridge Observatory just down the hill from Tom Krajci, is in the process of automating his systems and obviously knows the subject material inside and out. Smith began the presentation by defining automation and distinguishing the three types thereof, followed by explaining how to automate with the various software and hardware components that must be integrated. The presentation then logically trailed into scheduling time and targets. He wrapped up the effort by cementing the concepts of remote observatory site selection.

Three types of observatory automation were addressed in Smith’s presentation: • Manual observatory startup with telescope and CCD operating under scripted control for the night’s observations, followed by a manual observatory shutdown and subsequent manual data analysis.

• Remote, fully automated observatory operation with manual remote observation.

• Robotic remote observatory operation with scripted observatory operation and telescope and CCD scripted operations.

Of these three automation types, the first is the most common and easiest to implement, but requires an on-site presence.

The second type of automation enables multiple users to select and dynamically interact with their targets such as the modality of commercial observatory sites used by subscription. Finally, the remote fully automated observatory is the most efficient and least error prone, thus most commonly used for scientific applications.

After establishing the type of automation schemas, Smith explained how to make control systems accomplish basic tasks in terms of data, monitoring and safety. A good automation system plan should begin by considering: weather data as part of the control plan, data flow (cabled or wireless), protective sensors and features to prevent damage to people and equipment, system monitoring schema, integration of software and hardware to make it all work, and building a

bullet-proof emergency shutdown plan.

After an excellent discussion of the various software integration methods and options available, Smith addressed target scheduling in terms of easy and difficult scheduling. He asserted that easy schedules include time-series and single set deep imaging, whereas difficult schedules include supernova patrol or many target field images.

Considerations when developing a scheduling plan include: length of target observations and time visible, target queue ordering to maximize photons captured and minimize scope movement, concurrent study target observation overlap, target prioritization schemes and weighting targets of opportunity: GRB Alerts, AAVSO Alerts and outbursts. Given the nature of weather (pun), anyone controlling a schedule must understand the difference between static and dynamic schedules and be able to respond to weather effects by either accepting a loss or re-prioritizing targets.

Unfortunately, I missed Russ Genet’s short presentation on “High Natural Frequency Mechanical Structures” while I stepped out to coordinate a phone patch to Richard Kay for the alt-az bearing discussion.

However, immediately following Russ, Richard Hedrick provided an outstanding presentation “The Structural Alternatives.”

Rick addressed four topical areas: the motor/encoder/bearing, optical design, mount materials, and optical construction.

One of the most useful discussions of the day, Rick led the group to reach a participatory conclusion on the best type of design for an advanced alt-az telescope. In order to maximize both instrument placement and eyepiece accessibility, we assumed a CDK tertiary system on a ground plate constructed of advanced aerospace materials. In this case advanced aerospace materials include honeycomb structures bonded with structural adhesives, fabricated by smart machines.

Given that stiffness increases as the third power of honecomb depth, honeycombs are indeed the honeypot for this design.

The workshop wrapped up with a “Bearings for Alt-Az Telescopes” discussion

led by Richard Kay, President of Impact Bearings, whose point of presence was actually in San Clemente due to another air travel debacle. Of course the bearing discussion was not about traditional radial contact bearings. Richard Kay led the workshop through his product line including four point contact face-to-face and back-to-back bearings. In the b2b design, the outer rings abut and the inner rings are drawn together. The converse of this is true for f2f bearings. Additionally, we addressed Richard’s apparent favorite design, the Gothic Arch. The Gothic Arch contains half the amount of roller balls and maintains a longer life.

The Results The AATW hosted by the Texas Astronomical Society of Dallas indeed launched a revolution in telescope design.

The availability of low cost materials, control technology, and optical designs mean that it is possible today, using mostly simple hand tools, to assemble a large, highly capable telescope for a fraction of the cost seen a decade ago. This revolution will only come to fruition if the “visioneers” are steadfast in their ideals and control design, development, material, and production costs such that this system does not evolve into a would-be mountaintop telescope. Should the project remain true to its roots, Albert would indeed be proud of us. The image (below) is scaled to the size of our proposed telescope.

For more information on the Texas Astronomical Society of Dallas and its programs go to www.texasastro.org.

Astronomy TECHNOLOGY TODAY

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Demystifying Mirror Coating Technology Optical Mechanics, Inc. Provides an Insider’s Look at the Mirror Coating Process Programming the coating machine at Galco in Dallas Pictured Left to right, Dave Pasley, Marion Shafer, Ed Carr

By James Mulherin

At Optical Mechanics, Inc. (OMI) we’ve been making mirrors for the amateur astronomy community since 1991. Until recently we have subcontracted to various vendors for our mirror coatings, all the while looking forward to some day adding an optical coating machine to our company. That day has finally come. In October of this year we installed a coating machine at our facility in Iowa City. We are using the machine to coat the mirrors that we produce at OMI and we are offering mirror recoating services to the amateur community. In this article I will briefly describe the history of our coating machine acquisition, some of the key factors in the design of the machine and the technology incorporated to make the finest coatings available. Finally, I give a blow-by-blow description of the process using our particular machine to take some of the mystery out of mirror coatings.

History The benefits of coating mirrors in-house are obvious: faster turn-around, less shipping and handling and hence lower risk of damage. Most importantly, process and quality

60 Astronomy TECHNOLOGY TODAY

control are in our hands. Having accomplished our goal of acquiring a machine, here’s a quick look back at how the acquisition came about.

When I started making mirrors in 1987, I was fascinated by all aspects of the process, including mirror coating, but had little knowledge of how coatings were applied. I made my first mirror while studying Physics at the University of Iowa. With every Physics course comes a lab component and it just so happened that one of the labs covered basic vacuum technology, something often used in experimental physics. I completed the vacuum lab and then talked my professor into letting me coat my first mirror, an 8-inch f/4.5, when I completed it. Unfortunately I wasn’t able to complete the mirror in time so I sent it off to a coating vendor instead. I asked a lot of questions of the vendor, but got the typical response: “Our process is proprietary.”

As the business grew we continued to send mirrors out for coating and I continued to wonder about the process and whether it was something we could eventually do inhouse. In 1998 I bought a dilapidated bell jar

coating machine with the intent of temporarily applying aluminum coatings to Cassegrain secondary mirrors, just to have enough reflectivity to test the secondary against an uncoated primary. This was to be a time saving measure, not having to await the return of the secondary in order to finish the primary mirror. Unfortunately the machine was too far gone to rebuild. It was essentially gutted of all wiring, rusty and the diffusion pump was gummed up with burnt oil. I hadn’t spent much on the machine and definitely got what I paid for. The machine was eventually scrapped.

About two years ago our production volume hit the point where I had to get serious about buying a coating machine. I researched the current state of coating technology, read some books on thin film design and practical production of thin films and then contacted some coating machine manufacturers. The quantity and size of mirrors we make at OMI would require a large machine with some special features. I found out that a new machine of the right size, with the right technology would cost well over $500,000. This price was not cost feasible for a company of

our size so I started looking for used coaters that would fit the bill. Coating machines are used for a variety of applications, many related to the semi-conductor industry, and there are lots of used machines out there.

Unfortunately, not many of them are suited to coating large aperture mirrors. Finding the right machine would take some time. About a year ago I became acquainted with Marion Shafer The first batch of mirrors, three 12.5-inch, loaded at Galco Electronics in and ready to coat Mesquite, Texas. Marion is a reflection that the material can provide. As coating machine specialist. His small comthe aluminum is applied the reflectivity inpany specializes in refurbishing and moderncreases to a maximum of ~88% in the visible izing vacuum chambers for various purposes. spectrum. A standard aluminum coating inAfter many detailed conversations, Marion cludes one layer of SiO2 on top of the aluhad a complete understanding of our needs minum. The basic protective SIO2 overcoat and I had learned a great deal about practical is only thick enough to seal the aluminum aspects of coating mirrors and what to look from the elements and provide a hard, for in a machine. We both knew exactly what scratch resistant layer. It’s not intended to enI wanted. All we had to do was find the right hance the reflectivity. This type of coating is machine so Marion could work his magic on commonly referred to as Protected Aluit. Here’s a quick synopsis of what we were minum. looking for and why.

If you can control the thickness of the SiO2 layer well enough you can enhance the Technical Background and reflectivity by applying 1/2-wave thickness of OMI’s Coating Goals SiO2. By applying 1/2-wave of SiO2 the reOur specialty is enhanced aluminum flectivity is increased to about 91% in the viscoatings for the visible spectrum. The coating ible spectrum. Many coating labs refer to this consists of a base layer of aluminum followed aluminum plus 1/2-wave SiO2 as Semi-enby alternating layers of silicon dioxide (SiO2) hanced Aluminum. and tantalum pentoxide (Ta2O5).

If you take the semi-enhanced aluA standard coating consists of just minum coating and add a 1/4-wave thickenough aluminum to achieve the maximum

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DEMYSTIFYING MIRROR COATING TECHNOLOGY Low stack or HL stack. Most labs refer to this single HL stack coating as Enhanced Aluminum.

To continue to increase the reflectivity you add additional HL stacks. You can increase the reflectivity to about 98% with two HL stacks, in other words; Al, SiO2-Ta2O5, SiO2-Ta2O5. These are typically branded as proprietary enhanced aluminum coatings. All The finished product, three freshly coated of the above coatings are subject 12.5-inch mirrors to fiddling and fine tuning deness of titanium dioxide (TiO2) or tantalum pending on factors such as evaporation pentoxide (Ta2O5) the reflectivity is inmethod, process temperature and ion assist, creased to about 96% in the visible. For varwhich I will discuss in more detail. ious reasons we chose to work with Ta2O5.

I’ll return to discussion of the base layer This two layer stack consisting of SiO2, with of aluminum. Under high vacuum pure alua high index of refraction, and Ta2O5, with minum metal is melted then evaporated. It a low index of refraction, is called a Highcondenses on the mirror surface to form the

62 Astronomy TECHNOLOGY TODAY

aforementioned base layer. The quality of the aluminum layer is critical to the final quality of the coating. Conditions on the glass and in the coating chamber have to be right in order to obtain a bright aluminum coating with maximum reflectivity.

Before deposition of the aluminum layer the glass surface must be very clean. Cleaning a mirror with soap and water, followed by alcohol, is just the beginning. Immediately after drying, the mirror surface begins to adsorb water molecules. By this I mean water molecules are attracted and stick to the mirrors surface. These adsorbed molecules, if not removed, will reduce the adhesion of the aluminum layer. Poor adhesion of the aluminum layer is a common cause of coating failure. The coating will eventually flake off or rinse away in patches when the mirror is washed.

All residual organics must also be removed from the mirror surface. Organic contaminants will show through the aluminum layer. They also reduce adhesion. To remove adsorbed water vapor and residual organics the mirror receives a “scrub” with an ion mill prior to applying the aluminum. This takes place under vacuum. The ion mill produces a high energy plume of ionized argon gas that removes both water vapor and residual organics from the mirror surface.

The overcoat layers also take advantage of the ion mill. As these layers are deposited the ion mill is turned on. The mill provides an appropriate amount of energy to the depositing overcoat molecules to “hammer” them into place. This is called Ion Assisted Deposition or IAD. During IAD the high energy argon ions impinge upon the overcoating molecules as they are deposited resulting in higher density in the coating layer.

A good analogy for comparing non-IAD to IAD deposition is frost vs. freezing rain. A dense, freezing-rain-like coating is desirable.

A coating that lacks proper density will absorb moisture causing a shift in refractive index which affects reflectivity. A porous coating also allows contaminants to attack the aluminum base layer which causes premature deterioration and loss of reflectivity.

DEMYSTIFYING MIRROR COATING TECHNOLOGY tal element to a metal base layer.

To effectively remove water vapor a cryogenic vacuum pump is used. A cryo-pump is simply a very cold surface in the vacuum chamber that freezes out residual water and gas molecules to reduce the pressure in the chamber. The temperature of the cold surface in a cryopump is a little below 10 degrees Kelvin. That’s just 10 degrees C above absolute zero, as cold as Three freshly coated 18-inch mirrors anything gets. The cleanest, driest, lowest levels of vacuum are provided by cryogenic pumps.

An oil diffusion pump with a cold trap would be a good option, but the possibility of oil back-streaming into the chamber is a big negative. Marion and I decided that an oil-free cryopump system was highly desirable in our future coating machine to maximize the adhesion and reflectivity of the aluminum layer.

Three freshly coated 20-inch mirrors The aluminum and over coating layers can be evaporated from thermal sources such as a hot tungsten filament, a tungsten coil wrapped crucible or other type of tungsten “boat.”

To control the rate of evaporation and hence deposition on the glass the evaporation rate is monitored and the current through the tungsten is adjusted to provide the desired rate. The reaction time in this process is comparatively slow resulting in Freshly coated 30-inch mirror poor control of evaporation Understanding all of this, we knew that we rates. Better control can be obtained using an wanted an ion mill in our coating machine. electron beam source to evaporate the coating It is very important that the aluminum materials. The e-beam produces a current of be evaporated in a very low pressure envihigh energy electrons that are steered to the ronment if the reflectivity of the base layer is top of a crucible containing the coating mato be maximized. One of the hardest residuterial to be evaporated. Steering of the eals to pump out of a coating chamber is water beam is accomplished by a variable magnetic vapor and water vapor is the most detrimenfield. In addition, the magnetic field can be

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DEMYSTIFYING MIRROR COATING TECHNOLOGY The crystal frequency is fed to a controller that determines the evaporation rate and adjusts the current to the e-beam accordingly. This closed loop monitoring/controlling process happens many times a second resulting in precise control of the evaporation rate and, ultimately, precise control of the coating thickness.

The controller automatically turns off the e-beam and closes the shutter over the evaporant to 10-inch cryogenic pump on the side of the chamber stop deposition when the precontrolled to impart a sweep pattern to the eprogrammed thickness has been deposited. beam. Sweeping across the top of the mateWe obviously wanted an e-beam to evaporial in the crucible with an appropriate sweep rate our coating materials, and one with inpattern and speed results in a more uniform dexable crucible pockets no less, with at least plume of evaporant. Adjusting the current one pocket for each material that we would in the e-beam controls the power delivered deposit. to the material and hence the evaporation Having agreed on the key features of our rate. The evaporation rate is monitored using coating machine, Marion, at Galco, went to an oscillating crystal situated above the evapwork locating an appropriate candidate. In orating material. The frequency of the crysApril of this year Marion called to say there tal changes as material deposits on its surface. was a machine available that has everything

64 Astronomy TECHNOLOGY TODAY

we need except for the ion mill, which he could add for us, along with mirror holders/rotation fixtures and a modern PLC control system to automate the process. My heart raced as he described the machine to me: A 48-inch box coater with two cryo-pumps, a 20-inch and a 10-inch. This translates into incredible pumping speed and a very clean, dry vacuum. The machine also had a 4pocket, indexable e-beam source that was perfect for our application. Marion offered to refurbish the machine, add a Veeco Mark II+ ion mill, an Inficon IC5 crystal monitor/e-beam controller package, plus a planetary rotation fixture to hold up to three 20-inch mirrors in the chamber or one mirror up to 46-inch in single rotation. I couldnâ&#x20AC;&#x2122;t believe my ears. This was the perfect machine and the price was right!

A few weeks later I made the trip to Galco to have a first look at the machine and meet with Marion and Ed Carr, a retired coating engineer who I hired as a consultant to design our coatings and help â&#x20AC;&#x153;groomâ&#x20AC;? the machine, as Ed put it. The machine was

DEMYSTIFYING MIRROR COATING TECHNOLOGY grammed into the machine, so We make our own deionized water for the it was time to coat some real final rinse and follow that with an alcohol mirrors. We loaded three 12.5wipe. The mirror is then place in the clean inch mirrors in the planetary room where it is loaded face down into the holder and hit “Go.” A very machine. Mirrors 20-inch in diameter and nervous hour later we had three smaller are loaded in a planetary fixture that beautiful 12.5-inch mirrors. The holds three mirrors in a clover leaf pattern. witness samples that ran with During coating, each mirror rotates around the mirrors tested just like the its axis while all three rotate around the censamples in the previous test ter of the coating chamber. The rotation enruns. We all breathed a sigh of sures very uniform thickness in each coating relief and wished we had layer. Mirrors larger than 20-inch are coated brought a bottle of Champaign. one at a time while rotating in the center of The coating machine installed at OMI's lab We settled for bottled water and the chamber. Before the chamber door closes more impressive than I had imagined. It was proceed to coat the next batch of mirrors. each mirror is blown off using filtered, dry made almost entirely from stainless steel and Long story short: in two and a half days we air from an anti-static gun. This removes any looked brand new. Marion explained that the successfully coated all forty of the mirrors dust particles that may have attached themmachine originally cost over a million dollars that we had brought down with us. All of the selves to the mirror after the final wipe. We in 1989 and that he had high expectaalso add witness samples at this point. tions for our relatively simple coating After coating, the witness samples are process. We talked tech, then made measured for reflectivity, subjected to plans to come back to Galco in a couple adhesion and abrasion tests, serial numof months to learn how to use our bered and filed away. newly refurbished and upgraded maAfter loading materials (Al, SiO2, chine. I asked Marion if we could bring and Ta2O5) into the e-gun crucibles the some mirrors to coat after we got our chamber door is closed. Most of what training. He thought that would be a follows happens automatically after very good idea. starting the programmed coating cycle.

On September 10 Dave Pasley and The mechanical rouging pumps come I showed up on Marion’s door step with on to pump the chamber down to the forty (40) mirrors ranging from 12.5point where the cryo-pumps can take The ion mill used for Ion Assisted Deposition (IAD) inch to 30-inch diameter, ready to coat. over. This is called the cross-over presNeedless to say, Marion was a bit surprised witness samples run with each batch of mirsure and it is set at 50x10-3 Torr. When by our ambitious plan to coat forty mirrors, rors measured very close to our target and cross-over is reached a valve closes to isolate but took it in stride. With the help of Ed well within spec. The machine was producthe chamber from the mechanical pumps Carr we made test runs, coating microscope ing a very consistent coating. We drove home and they turn off. The cryo-pump valves are slides, to get each coating layer set up indiquite pleased with our acquisition and with a then opened and the pressure in the chamber vidually. Then we made test runs of our van load of coated mirrors to boot. Our continues to drop. three-layer enhanced aluminum coating to thanks to Marion Shafer at Galco for buildWhen the pressure reaches 1x10-5 Torr, fine tune the process. I had brought our new ing us such a fantastic machine and to Ed mirror rotation is turned on and the first ion spectral reflectometer to Galco and we used Carr for designing and setting up the process scrub begins. At this point the inside of the this instrument with good success to measfor us. These guys are really good at what chamber is brightly illuminated by the ion ure our coating results, both reflectivity and they do. mill and the uncoated mirrors are visible layer thickness. The final result on the test through the upper view port in the door of slides was a 96% coating with excellent adthe coating chamber. After the first ion scrub OMI’s Coating Process hesion, no pinholes and a very durable top the pressure is allowed to drop to 8x10-6 Torr After much preparation the coating masurface. The coating passed the MIL spec for and a second ion scrub is performed. After chine is now set up and running at OMI’s faadhesion (tape peel test) and abrasion (eraser that the chamber pressure is allowed to drop cility in Iowa City. Following is a brief rub test) with flying colors. to 5x10-6 Torr while at the same time waitdescription of the process. As mentioned, the We had our coating process proing for the temperature in the chamber to mirrors are first cleaned using soap and water.

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DEMYSTIFYING MIRROR COATING TECHNOLOGY

RAW MATERIAL

SiO2

Aluminum

Ta2O5

reach the preset temperature for aluminum evaporation.

Now the mirrors are ultra clean and conditions are right for evaporation of the aluminum. The carousel indexes to the crucible containing aluminum pellets and the e-beam turns on. Initially the e-beam power is low to heat soak and bring the aluminum up to the melting point. This is followed by a second soak to bring the material up to evaporation temperature. Then the shutter is opened and the crystal monitor and Inficon controller take over to achieve the desired deposition rate and apply the desired thickness of aluminum. There is a lower view port on the door of the machine so you can watch the aluminum melt in the crucible, or you can watch the mirrors through the upper view port as they rotate and go from clear to reflective. This is really something to see. All of the light in the chamber during this process emanates from the molten aluminum in the e-gun crucible. You have to view the molten pool of aluminum through crossed polarizers as it is too bright to view with the naked eye.

When the desired thickness of aluminum has been deposited the shutter covers the aluminum crucible, the e-beam turns off and the carousel indexes to the next crucible containing silicon dioxide. The process repeats for SiO2 but this time the ion mill is turned on to provide ion assist to create a dense layer of SiO2.

This process is then repeated for the Ta2O5 layer.

After deposition, valves close to seal off the cryo-pumps and a relief valve is opened to

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allow air back into the chamber. The door can then be opened and the coated mirrors unloaded. That’s it! One coating cycle, including loading and unloading the mirrors takes 70 minutes to complete. In an 8-hour shift we can make five or six coating runs. As I write this we’ve coated over eighty mirrors with the new machine.

Not all of the material that is evaporated makes it to the mirrors. Some of it condenses on the walls of the chamber and on a heat shield above the mirrors. The inside walls of the chamber are covered with aluminum shields that collect the over spray of evaporated materials. These shields must be removed occasionally for bead blasting to remove the accumulated deposits.

Will an Enhanced Coating Change a Mirrors Figure?

I’m often asked if enhanced aluminum coatings change the optical figure of a mirror.

Consider the application of each layer of material. The layer most likely to change the mirrors figure is the aluminum layer as it forms the surface from which the light is reflected. The SiO2 and Ta2O5 layers are transparent. They act only to enhance the reflectivity. If they lack uniformity their primary effect will be a variation in the reflectivity across the mirror.

The aluminum layer is about 900 Angstroms thick or approximately 1/6-wave of visible light. A loose tolerance on coating uniformity is 5%. This is equivalent to 1/122-wave at the center if the visible spectrum. A more realistic target for uniformity is 2% or 1/300wave. A properly applied coating will not change the figure of the mirror by any significant amount.

Will an Enhanced Coating Scatter Light?

As I mentioned above, the SiO2 and Ta2O5 layers are transparent. It is possible to produce a frost-like layer that is porous and may scatter some light. This problem is more indicative of less than optimal processing than the number of layers applied. A coating layer that is porous can result from insufficient temperature on the mirror surface and insuffi-

DEMYSTIFYING MIRROR COATING TECHNOLOGY ciently low vacuum. Low temperature causes the coating molecules to freeze to the mirror surface before achieving proper packing density. A properly heated mirror surface provides the extra energy needed by the coating molecules to find their proper place in the coating layer.

Ion assisted deposition mitigates this problem as the argon ions from the mill provide the extra energy needed to maximize packing density, even at a lower mirror temperature. By supplying the needed energy, the ion mill produces very dense, hard overcoat layers.

Insufficient vacuum results in scattering and loss of energy in the coating molecules as they make their way from the evaporation source to the mirror surface via collisions with residual gas molecules. The result is similar to the above: low packing density. The cryopumps on our machine provide a very low vacuum so this is not a concern for us.

Summary There are many details that go into producing a high quality coating and I've listed

only a few of them here. There are many other factors on the input side of the coating equation.

The trick is to have a way of measuring the output and an understanding of which inputs to adjust to achieve your process goals. At the same time you need good process monitoring and real time control of the process.

OMI’s new coating machine uses e-beam evaporation with ion assist and deposition rate monitors with all of the machines functions controlled by a computer and programmable logic controllers (PLCs) for each of the sub-systems on the coating machine. Our coater is fully automated and self monitoring and it can reliably and repeatably run a well designed and de-bugged process to produce consistent results.

Much of the technology implemented in our machine was developed for the semi-conductor industry where coating designs can include hundreds of layers with very tight tolerances. The coatings we use on telescope mirrors are exceedingly simple compared to the capability of our modern coat-

ing machine.

I hope you’ve enjoyed this brief description of OMI’s mirror coating process and that it’s taken some of the mystery out of mirror coatings. I wondered about all of this for the longest time, but I couldn’t be more pleased with the result of my long search for answers to my questions and my quest for a mirror coating machine. Please contact me or Dave Pasley directly if have questions about our coating products. You can find more information about our coatings on our website at www.opticalmechanics.com.

Evaporating process as seen through the viewing window of the coating chamber.

Evaporating Aluminum. Note Orange color

Evaporating SiO2: Note yellow color

Evaporating Ta2O5: Note purple color

Astronomy TECHNOLOGY TODAY

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ASTRO TIPS tips, tricks and novel solutions Mike Jones' October article described a handy test for revealing stray light in your OTA and, not surprisingly, generated demand for even more coverage of the tips, tricks and novel solutions our readers bring to the nagging problems that vex us all. So, we've decided to, at least periodically, feature your favorite tips in place of the Reader Profile that normally resides here. We're starting this series with a few of our favorite tips, but encourage you to share yours by sending them to tips@astronomytechnologytoday.com. Enjoy, Gary.

light with one or more layers of red lens repair tape and the problem is solved. The stuff is generally available from any auto parts store for less than $2 roll. It looks like my roll will prove a lifetime supply.

Lighted Magnifying Glass

Red Automotive Lens Repair Tape I keep a roll of this stuff handy for covering those annoyingly bright indicator lights that threaten our dark adaptation.

You know the ones: the green "power on" lights on mount controllers, power packs, and too many other devices designed for our use at night. Just cover the offending

Submit Your Astro Tip! Astronomy Technology Today will feature Astro Tips from our readers. To be considered for a tip, email the following information: • A Microsoft Word document detailing your tip, trick or novel solution.

• A hi-resolution digital photo in jpeg format (if available).

Please send your information to tips@astronomytechnologytoday.com

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Astronomy TECHNOLOGY TODAY

As with magazines, I prefer print to digital when given the option and that includes sky charts. So, most clear nights find me studying print charts in the dark, but as I age I find it increasingly difficult to make out the finest detail on the field version of Sky Atlas 2000.0, even with my reading glasses and best red flash. I've solved this problem with a $2 lighted magnifying glass (I found mine at a Dollar General store). It boasts a 60-mm clear aperture lens, a too bright incandescent bulb (white) and is powered by two stan-

dard AA batteries. I used three layers of the red automotive lens repair tape to cover the bulb and ended up with the perfect tool for reading fine print in the dark.

Gaffer Tape Jim Osborne, our favorite pro photographer, introduced us to this stuff and we’ve since found it far more indispensable than the old standby, duct tape. This vinyl cloth tape has super grip, is water and temperature resistant, leaves very little residue when removed, and, best of all, is available in a stray light gobbling matte black finish. It’s great for on the spot coverage of any contrast eating shiny thing, plus anything else you’d normally cover or fasten with traditional duct tape. As to how well it holds, when the side view mirror of my van fell out of its holder while at the Winter Star Party in February, I reattached it with three small tabs of gaffer tape (I keep a roll in the van), intending a more permanent repair when I returned home. It’s now nine months later and the three tabs are still holding the mirror in place. Just Google “gaff tape” or “gaffer tape” for online sources.

Shortening a Bolt You need to shorten a bolt, but know you’ll never get a nut to thread on it after the hacksaw mangles a few threads on its way through. Just thread the nut on the bolt BEFORE you cut it. When you back the nut off, it “fixes” the cut threads and makes rethreading the nut a snap.

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