Perth Observatory Galaxia Magazine | June 2023

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Embark on an Unforgettable Journey

Our volunteers recount their Ningaloo Eclipse road trip and cruise!

Exploring The Secrets Of Jupiter’s Icy Moons

ESA’s Juice Mission Takes Flight!

Destination: Infinity and Beyond!

The epic story of SpaceX’s Starship and Super Heavy launch!

Astrophotography Unveiled

Discovering the Universe with Michael Goh, an exclusive interview

GALAXIA MAGAZINE

JUNE 2023

Do you have a passion for space and astronomy but never had the time to study it?

The Perth Observatory has organised a 5-week introductory course so you can learn about our amazing universe. Each week we’ll cover a different topic. We’ll have a Q/A session with tea and coffee before we head up to the telescopes for some hands-on practical experience. The course includes handouts of the relevant data, diagrams, and references.

Led by our experienced STEM Coordinator, Jenny Gull, you’ll have the chance to learn from an expert in the field.

ASTRONOMY 101 COURSE

Astronomy is one of the sublimest fields of human investigation. The mind that grasps its facts and principles receives something of the enlargement and grandeur belonging to the science itself. It is a quickener of devotion.

 Contents 05 A View Through The Eyepiece 09 Our Epic Eclipse Voyage 15 Casting Light on Twilight 17 The Subjugate Book Review 21 Cosmic Cruising 27 SpaceX Launches Starship 33 Celestial Jewellery 35 Cracking The Ice Find Us Here   
41 Twinkle, Twinkle, Giant Star 45 Stargazing Pioneer 49 Capturing the Cosmos 57 What’s In July’s Skies 60 What’s In August’s Skies 64 What’s In September’s Skies 69 Pan Galactic Gargle Blaster 76 The Funny Side Editorial
Contributors
Subscriptions Click Below to subscribe to our newsletter  Front Cover Image By Micheal Goh Back Cover Image By Roger Groom
Matt Woods Editor
Michelle Ashley-Emile, Paul Fisher, Mary Hughes, Ronny Kaplanian, Julie Matthews, Paul Jones, Carol Wolf, Matt Woods

A View Through The Eyepiece

The Perth Observatory has experienced an extraordinary first half of the year, and we want to express our gratitude to everyone who has attended our events. In March, we hosted our summer Lecture, where Dr. Sabine Bellstedt, an esteemed astronomer from the International Centre for Radio Astronomy Research (ICRAR), delivered a captivating presentation on the ground-breaking work of the James Webb Space Telescope (JWST) during its inaugural year. We are immensely thankful to Dr. Bellstedt for sharing her time and expertise.

April was an exciting month as we spared no effort to facilitate eclipse viewing, dispatching two teams with Astrotourism WA to Exmouth. One team did stargazing nights along the way and live-streamed the eclipse for a global audience, while the second team conducted three stargazing nights in Exmouth, drawing a remarkable crowd that even surpassed attendance at The Waifs concert. We also hosted eclipse-related events at the Observatory, including a captivating talk by Dr. Kate Russo on eclipse chasing and the emotional experience of witnessing such celestial events. On the day of the eclipse, over 200 individuals attended our partial eclipse event, where we provided a safe viewing opportunity and livestreamed the totality from Exmouth. Moreover, we brought solar scopes to the WA Museum in Northbridge, enabling 600 visitors to observe the partial eclipse.

In early May, the Bickley Harvest Festival attracted hundreds of visitors who braved the inclement weather to explore the Perth hills and indulge in the local orchards, wineries, and cideries. As they toured the Bickley Valley, many visitors stopped by the Observatory, where we offered guided day tours and engaging activities for their children. The recent rainfall has enhanced the beauty of the Bickley Valley and Perth hills, so it’s a great time to visit.

There’s been significant progress with our improvement projects. In early June, we were thrilled to receive one of our Shortt-Synchronome clocks back in working condition. These clocks, which have kept time in Western Australia for decades, were entrusted to Timepiece Creations in Kenwick along with our other clocks for restoration as part of our Lotterywest grant. Frederic and Nino have done an exceptional job.

Lastly, I would like to express immense gratitude to Zoé Fraussen, our former editor and esteemed colleague. Zoé has relocated to the Netherlands for work, leaving a significant void in our volunteer group. It was a pleasure collaborating with Zoé on these newsletters, brainstorming article ideas, and enhancing the design.

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The Helix Nebula NGC 7293

Upcoming Workshops

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Image Credit: Matt Woods

2nd of August

Astronomy 101 Course

Time: 7 pm - 8:30 pm (Doors open at 6:30 pm)

Price: $300 per person

Are you fascinated by the vast expanse of space and the mysteries of our universe, but never found the time to learn about it? Well, now is the perfect opportunity to discover more about our amazing cosmos!

Perth Observatory has a 5-week introductory course on space and astronomy, covering a range of topics. Led by our experienced STEM Coordinator, Jenny Gull, you’ll have the chance to learn from an expert in the field.

13th of September

Spring Into Milky Way Photography

Date: 13th and 14th of September

Time: 7 pm to 9:30 pm

Price: $210 per person for both nights

Take advantage of the Milky Way season and learn how to get the best out of your Milky Way photos. Over two nights, you’ll learn all the basics of Milky Way photography, and on the second night, you’ll have the opportunity to put your new knowledge to the test, taking stunning photos of the night sky from the Perth Observatory viewing area.

Don’t miss out on this incredible opportunity to learn the art of Milky Way photography.

29th of August

Lunar Photography Workshop

Time: 7 pm - 10 pm (Doors open at 6:30 pm)

Price: $120 per person

This promises to be a fun relaxed evening of photographing the Moon on some fantastic telescopes using your camera. Using a combination of Astrophotography Australia and Perth Observatory telescopes and equipment, we will have a wide range of focal lengths and types of telescopes available. You will be able to take breathtaking photographs of the moon that are at much higher magnification.

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Our Epic Eclipse Voyage

In 2015, during my first ever Astrofest planning meeting, a fellow attendee mentioned a special hybrid solar eclipse was scheduled to take place in Exmouth in 2023. I was thrilled at the prospect of witnessing my first total solar eclipse, although the event seemed distant at the time. As time tends to do, it crept up on us gradually. Before we knew it, five years had passed, then three, until we realised, we were only a year away from being in Exmouth. Finally, the morning of the eclipse arrived, and the anticipation was palpable.

Since that initial meeting, numerous events transpired, including our live streaming of five total and partial lunar eclipses for the website TimeandDate.com. About a year and a half before the eclipse, I discussed with Anne, Graham, and Steffen from TimeandDate.com the possibility of live streaming this hybrid eclipse. It would have been a missed opportunity not to share this

Image Credit: Tourism Western Australia

extraordinary event with the rest of the world, considering that Exmouth, located on the northwest Cape, offered the best viewing for the 59 seconds of totality.

Over the next nine months, we encountered various obstacles while searching for suitable accommodations with reliable power and internet connectivity to stream the eclipse. However, in August 2022, Carol Redford from Stargazers Club WA and Astrotourism WA brought us fantastic news. She had secured funding from WA Tourism for a comprehensive Eclipse Discovery Tour program, which would include astronomy nights in country towns along the coast and interior of Western Australia. Additionally, it granted us access to the prime viewing location for the eclipse, the Kailis Site 20 kilometres south of Exmouth. Carol asked if I could lead a team from Perth Observatory, and after consulting with the operations team, I happily accepted.

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Our chosen route was the interior route, taking us through various towns such as Morawa, Murchison, Mullewa, Bullara Station, and Gascoyne Junction. We also added stargazing nights in Dalwallinu, the night before the Morawa event, as well as Useless Loop and Dongara, following the Gascoyne Junction stargazing night. With the locations finalized, we embarked on a 12-day journey from Perth on April 14th, 2023, to witness the magical hybrid eclipse.

Securing access to view the eclipse was a relief, but we still faced one major challenge— ensuring reliable internet connectivity in Exmouth for the live stream. This is where Penny Griffin from the Department of Primary Industries and Regional Development (DPIRD) played a crucial role. Penny, a valued member of the astronomy community in WA, was tasked with the monumental responsibility of ensuring sufficient communication equipment for the

northwest Cape to accommodate 50,000 people. After helping DPIRD test the Starlink dish during the live stream of the total lunar eclipse in November 2022, Penny brought together the Gravity Discovery Centre Observatory, Telstra, and our team to devise a plan for accessing reliable internet. These meetings successfully resolved the issue, relieving us of this final challenge and leaving us with the task of organising our team.

Joining me on this extraordinary journey were fellow volunteers Jacob Einam, Coran Napier, Jodie Sims, and Ted Williamson. Jodie’s new Toyota truck and the trusty Europcar minibus served as our mighty steeds, and they would endure the 4,000-kilometer journey with us over the 12 days. We would travel on some of Western Australia’s most rugged roads, our adventure would rival some of the famous Top Gear specials.

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We bid farewell to a rain-soaked Perth as we embarked on our journey on April 14th. The welcome sight of sunshine accompanied us through the countryside as we headed towards our camping adventure. For nine out of the twelve days, we would be sleeping under the stars in our swags, and luckily, the good weather persisted until the eve of our return to Perth. As rain poured down, we found solace in a charming old train carriage at the Breeze Inn in Dongara.

Our trip to Exmouth was nothing short of fantastic. The astronomy nights drew a large and engaged crowd, with attendees posing intriguing questions. We were delighted to make new friends from Southern Illinois University, including Dr. Bob Baer and his team, who joined us with their telescopes for the awe-inspiring Morawa and Murchison stargazing nights. Witnessing their awestruck faces as they beheld the magnificence of the southern night sky for the first time was an unforgettable experience. At Murchison, we encountered our first crisis of the trip. In my haste, I mistakenly failed to secure our

Nikon D810a camera onto its tripod while capturing photos of the stargazing night.

I cringed as I heard a loud thud and saw the lens and camera separate, with the lens mounting still attached to the lens instead of the camera body. Panic set in as I realised this was the very camera intended for live streaming the eclipse.

The next couple of hours were a whirlwind of notifying others about the mishap and scrambling to find a replacement camera for the live stream. Fortunately, Jodie had brought along an extra Canon DSLR camera, which we could use for the live stream. However, we faced a hurdle as Jodie didn’t have the camera’s T-ring, preventing us from attaching it to the telescope.

Luckily, we managed to use the internet at Murchison to contact Jodie’s husband, Luke, who kindly arranged to meet Steffen, the CEO and Founder of TimeandDate.com who was coming to help us live stream, at the airport and provide him with the T-ring. Crisis averted, but challenges remained ahead.

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Morawa Stargazing Night. Image Credit: Matt Woods

While traveling from Murchison to Mullewa, an incident occurred involving a rock, that was flicked up by the minibus and hit the trailer, causing it to ricochet and shatter the back window. Although I heard a popping sound, no one else noticed, so we continued driving. Ten minutes later, Jacob alerted me to the draft in the back, prompting us to stop and investigate. To our dismay, we discovered the broken window and realised that Ted’s pillow had been ejected from the van during the impact.

Fortunately, Jodie and Coran spotted the pillow and retrieved it, mistaking it for someone else’s belonging. As we assessed the damage to the minibus, the local ambulance volunteers we had befriended the night before stopped by and offered their assistance. They guided us back to the ambulance site in Mullewa, where we could clean up the broken glass and secure a temporary cover for the back window, ensuring we could continue our journey after the stargazing night. We remain forever grateful to these extraordinary lifesavers.

The remainder of our journey to Exmouth proceeded without incident. On the day before the eclipse, we met up with Steffen, the Gravity Discovery Centre Observatory, and Telstra teams to set up for the live streams and conduct tests. Everything went smoothly, and it was truly remarkable to have reliable internet in the middle of nowhere, enabling us to share this mesmerising eclipse experience with the 20,000 people from around the world who had gathered to witness this celestial phenomenon.

On that Thursday, as I stepped out from underneath our marquee to conduct my interview with Thommo from Channel 9 news at 11:10 am, I immediately noticed a remarkable change. The radiant heat from the sun seemed to disappear, and the darkness intensified. It was awe-inspiring to witness the landscape gradually grow darker and darker. At 11:29 am, the shadow of totality emerged from the southwest and enveloped us for the next 59 seconds. In that brief span of totality, I witnessed one of the most breathtaking sights I have ever seen.

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Image Credit: Perth Observatory volunteers

The sun was completely obscured by the moon, creating a black disc, and the Sun’s radiant corona captivated our gaze. To my astonishment, I also observed patches of purple, representing enormous solar prominences on the sun’s surface. It was a stunning spectacle, albeit disappointingly brief, as if the universe was teasing us, offering just a taste of what could have been. Some total solar eclipses can last anywhere from 1 to 5 minutes of totality. Dr. Kate Russo, an eclipse chaser with extensive experience, had accurately predicted that the first thought crossing my mind after totality would be, “When is the next eclipse?” She was absolutely right.

Later that night, we returned to Bullara Station for a celebratory meal with the rest of the Eclipse Discovery Tour. The following day, we took our first break of the trip at Coral Bay, where we joined one of our fellow volunteers who works there, extending the festivities into the night. The subsequent day brought us to Gascoyne Junction, where we organised another memorable stargazing night. If you ever find yourself near Carnarvon, I highly recommend visiting the enchanting town of Gascoyne Junction. It offers breathtaking scenery and the stunning Kennedy Ranges, which are well worth a visit.

With fond farewells, we departed Gascoyne Junction early the next morning, as our journey led us to Useless Loop on the other side of Shark Bay, across from Denham. We made excellent progress until we reached the unsealed part of Useless Loop Rd. Due to issues with the local council, the road was a complete mess, and it took us three hours to drive just 100 kilometres. Those three hours was such a rough and bumpy ride, in the minibus as we pulled the trailer.

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Image Credit: Jodie Sims Useless Loop. Image Credit: Matt Woods

Upon our arrival at Useless Loop, we were greeted by stunning views of Shark Bay, the town, and the salt lakes. We soon realised that the arduous three-hour journey and the upcoming three hours it would take us to depart the next morning were worth it to experience this remarkable place. To our delight, approximately two-thirds of the town’s population (60 people) attended the star gazing events at the airport. We were immensely grateful for their presence, considering the wear and tear our equipment had endured during the journey, leaving the trailer quite dusty.

The following night, we found ourselves in Dongara, yet our luck with the weather had run out. It remained cloudy for most of the night. However, we didn’t let that dampen our spirits. We conducted presentations for the attendees, and just as we were wrapping up the final session, the sky cleared, granting us a precious opportunity to showcase a few celestial objects through the telescopes before bidding farewell. The next morning, we rose early to attend the ANZAC Day dawn service before making our way back home. It brought a sense of relief to return to Perth, marking the end of a remarkable adventure during which we shared the wonders of the night sky with over 600 people and experienced our very first total solar eclipse.

In the following weeks, Steffen from TimeandDate.com provided astonishing statistics about the reach of our live stream on YouTube. We garnered millions of views solely on our YouTube channel, and when accounting for other YouTube pages that borrowed our stream, we reached an impressive 14.5 million people on YouTube alone. This figure skyrocketed when considering the additional viewership from television, news outlets, and media agencies that also utilised our live stream. In total, we estimate that our coverage reached over 100 million people—an astounding achievement that left me in awe.

Noteworthy international usage included prominent organisations such as NASA, BBC News, Associated Press, CNN, NBC, Al Jazeera, New York Times, Washington Post, Wall Street Journal, as well as Australian networks like ABC, SBS, Channel 9, Channel 7, Sky News, The Guardian, and many more. Even Sony Music Australia incorporated segments of our live stream into their own broadcast, for Pink Floyd’s celebration of the 50th anniversary of their iconic album, “The Dark Side of the Moon.”

Reflecting on the trip, I am eternally grateful for the opportunity to witness the Ningaloo Solar Eclipse. I extend my heartfelt appreciation to my team, Carol, Penny, the Telstra team, and the dedicated individuals at the Department of Jobs, Tourism, Science, and Innovation, including Glenn Shoebridge, the Event Development Manager for the Kailis Site. Glenn played an instrumental role, guiding me throughout the eclipse preparations and ensuring that all our questions were answered, and every need was met on the day. Without the support of these remarkable individuals and organisations, our voyage would not have been successful, and we would have missed the chance to witness this extraordinary eclipse.

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The Weary Travellers Return. Image Credit: Luke Sims

Casting Light on Twilight Exploring the Diverse Shades of Dusk

Sunrise and sunset hold a magical allure, marking the moments when the sun’s upper limb graces a level horizon. These instances represent the first appearance or final disappearance of the sun for observers at sea level and over a sea horizon. However, it is crucial to acknowledge that factors such as trees, hills, buildings, and observer elevation introduce slight variations in timing for other locations.

The twilight period, which precedes sunrise and follows sunset, is divided into three distinct stages: Civil Twilight, Nautical Twilight, and Astronomical Twilight. While the following descriptions pertain to evening twilight, they also apply in reverse to morning twilight.

CIVIL TWILIGHT:

Civil Twilight concludes when the sun rests 6° below the horizon. Beyond this point, ordinary outdoor activities become impractical without artificial light. Traditionally, streetlights were switched on at the end of Civil Twilight, a practice still observed in some rural areas. However, many regions now employ light meters for control, typically activating streetlights approximately 10 minutes before Civil Twilight concludes.

NAUTICAL TWILIGHT:

Nautical Twilight ends when the sun descends 12° below the horizon. At this stage, the horizon is no longer visible, except in the direction of sunset, where a faint twilight may persist. Nautical Twilight marks the onset of ideal conditions for astrophotography, except in western sky areas. For most practical purposes, it would be deemed “dark.”

ASTRONOMICAL TWILIGHT:

Astronomical Twilight concludes when the sun dips 18° below the horizon. By this point, residual sunlight falls below the threshold to illuminate the night sky.

In Western Australia, the duration of each twilight stage exhibits minimal yearly fluctuations, differing only by a few minutes. Roughly, Civil Twilight begins or ends approximately 25 minutes before sunrise or after sunset, with the other two stages preceding or following at intervals of approximately 30 minutes.

These descriptions apply to clear, normal conditions. However, heavily overcast skies can significantly diminish illumination. Thus, meteorological conditions must be taken into account. In the absence of meteorological variations, an assessment of illumination at a specific date, time, and location can be obtained by visiting the site on another day at the equivalent time before sunrise or after sunset.

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Image Credit: Matt Woods

THE SUBJUGATE

A year or so ago, whilst browsing the book tables at Supanova, I was reading the back cover of “The Subjugate” when a bubbly voice piped up “What do you think of the cover?”

Born in Geraldton WA, Amanda earned her BA in Communication Studies from Murdoch and has racked up a huge portfolio of novels, novellas and short stories.

“Umm, intriguing” I replied.

“Do you like mysteries? Science Fiction mysteries?” a smiling young woman asked.

“Yep, I love ‘em” I enthused. “I’ve never read any from this author though, is she any good?”

“Well, she’s written a lot of books and I think so” she smiled. “After all, it’s me!”

We both burst into laughter and immediately began chatting like we’d known each other for years. Authoress - Amanda Bridgeman is warm, vibrant and intelligent.

She has won and been shortlisted for numerous awards and enjoys working across different genres both original and media tiein fiction, including a novel and short story in the Marvel X-Men universe.

Promising to work my way through her huge repertoire of novels and clutching my now autographed copy of “The Subjugate”, I scurried off to get started. “The Subjugate” had me gripped from the beginning. This scifi thriller is part of the Salvation series and is being developed for TV by Anonymous Content (Mr Robot, The Alienist, True Detective), Aquarius Films and has received development funding from Screen Australia.

The blurb read:

“In a small religious community rocked by a spree of shocking murders, Detectives Salvi Brentt and Mitch Grenville find themselves surrounded by suspects. The Children of Christ have a tight grip on their people, and the Solme Complex neurally edit violent criminals –Subjugates – into placid servants called Serenes. In a town where purity and sin, temptation and repression live side by side, everyone has a motive. But as the bodies mount up, the frustrated detectives begin to crack under the pressure: their demons are coming to light, and who knows where that blurred line between man and monster truly lies…”

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Image Credit: Amanda Bridgeman

And the book delivers! It’s well written, extremely tense at the end and scarily believable. The characters are fascinating and there were enough twists and turns to keep my heart hammering and stop me from putting the book down. It even got a unanimous thumbs up from my longsuffering Book club.

This old school whodunnit cleverly set in our highly possible future is a great read and one of my favourites. I can’t wait to read more of Amanda’s work.

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Image Credit: Amanda Bridgeman

Join our School Day Tours Team

Looking to volunteer and make a difference in the lives of primary school children? If you have free time during the day and a passion for learning about space and our solar system, we invite you to join our School Day Tours Team as a volunteer!

As a member of our team, you will have the opportunity to share your knowledge and enthusiasm with young students while learning from experienced educators. No prior experience is necessary, as we provide all the training you need.

If you enjoy working with children, this could be the perfect opportunity for you! All you need to bring is your enthusiasm, a friendly demeanour, and the ability to communicate with children.

To learn more about how you can get involved, click below and let’s start making a difference in the lives of young students today.

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Messier 83 The Southern Pinwheel Galaxy PAGE 20 2023 WINTER EDITION
Image Credit: Ronny Kaplanian

Cosmic Cruising

Catching the Ningaloo Eclipse from the High Seas

I have always wanted to see a total eclipse, and well blow me down there we had it right here in Western Australia. 20th April 2023 will forever be etched in my mind. Wow! What an experience!

When I realised that an eclipse was going to happen in 2023, I looked around for an option to get to Exmouth and view it. That was challenging as the accommodation in Exmouth was already pretty much sold out. Exmouth is not a big town and has limited availability of accommodation anyway. I posed the question to the Perth Observatory Volunteers group and the ever-resourceful

Bevan Harris came up with a few suggestions one of which was a P&O cruise on the Pacific Explorer. That’s it I was sold! I organised the trip through Tropical Sails with a group and I was glad I did as we got good accommodation with group access to restaurants etc.

So we would be arriving in Exmouth Gulf on the morning of 20th April and viewing from the ship. This group of 55 people had all seen multiple eclipses over a period of years; one couple had seen 18 all over the world. The advantage that this gave us was knowledge of what to expect and how to view properly.

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We were not disappointed, the atmosphere was amazing as the sky darkened, everything around us seemed to go still, and there was an eerie hush. We were told that totality phase is safe to view without the solar glasses we were using during the partial eclipse phase. By then, less than 0.001% of the Sun’s photosphere is visible. We took our glasses off for the expected Baily’s Beads and the Diamond Ring, and we saw it all!

There was a guy next to us who was filming the whole sequence and he had never quite got it right until this time. He had an email from his son telling him that his first grandchild had just been born and then he found his filming had worked. He was so overcome with it all, he was in tears. It was a totally amazing experience for us all.

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Image Credit: P&O Cruises
Oh dark, dark, dark, amid the blaze of noon. Irrecoverably dark, total eclipse. Without all hope of day!
– John Milton, English poet and intellectual.
Image Credit: Jamie Carter

Much as I would like to claim this picture, I cannot - but this is what I actually saw! The activity around the edges was bright and clear. I was told that I was very lucky for a first timer as not all totalities are so productive. Just to explain about the beads, they are an arc of bright spots seen during total and annular eclipses of the Sun. They are named for Francis Baily, an English astronomer, who called attention to them after seeing them during an annular eclipse on May 15th, 1836.

But apparently Sir Edmond Halley made the first recorded observations of Baily’s beads during the solar eclipse of May 1715. He described and correctly ascertained the cause of the effect in his “Observations of the late Total Eclipse of the Sun”.

I’m very tempted to go in 2028 so I’m staying in touch with the group who may be able to predict the best place to go, I hope. Somewhere from Kununurra to Sydney…go figure that out and perhaps I might see you there!

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Image Credit: Mary Hughes

Telescopes Under

Western Australia’s Skies

Looking for an unforgettable night under the stars? Look no further than Perth Observatory’s offsite astronomy nights! As Western Australia’s leading Observatory, our experienced volunteers are dedicated to sharing the beauty and wonder of the night sky with people across the state.

Our team will bring their top-of-the-line telescopes and expertise to your town, suburb, or school, providing you with a unique and immersive journey through the Southern Hemisphere’s celestial wonders. We will also guide you through the night sky with the help of our green laser, teaching you about the stars, planets, nebulas, dying stars, and enormous star clusters that populate our universe.

Whether you are an astronomy enthusiast or simply looking for a fun and educational experience, our offsite astronomy nights are the perfect way to explore the beauty and complexity of our uni-verse. Request your night under the stars below and discover the magic of Perth Observatory!

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Image Credit: Matt Woods

The Night Sky

At Gutha Hall, Morawa

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SpaceX Launches

Starship and Its Super Heavy Boosters

In a momentous event that has blown the minds of space enthusiasts around the world, SpaceX has achieved a major milestone with the launch of its Starship spacecraft. While not completely successful, this achievement marks another significant step in the company’s ambitious vision to revolutionize space travel and lay the foundation for interplanetary colonisation.

The historic launch took place on Thursday the 20th of April in the morning at SpaceX’s Starbase, in Boca Chica, Texas. Spectators and space enthusiasts gathered in anticipation as the massive stainless-steel Starship spacecraft, standing at an impressive 120 meters tall, was fuelled and prepared for its inaugural launch. The plan for the launch had been to send Starship on one near-complete revolution of the Earth, ending with a splashdown in the Pacific, a couple of hundred kilometres north of Hawaii. There was no expectation that both Starship and the Super Heavy Booster would be recovered this time, but the long-term plan is to land both the spacecraft and Booster, refuel them and launch again - over and over.

As the countdown hit zero, Starship, and its Super Heavy Booster, took a full 6 seconds to lift off the launch pad. Starship majestically soared through the Texan morning sky for a few exhilarating minutes, but the rocket failed to get high enough for Starship to separate from the Super Heavy Booster as planned, and the huge rocket began to tumble, requiring SpaceX to send the commands for Starship to self-destruct, which happened high above the Gulf of Mexico four minutes into the flight.

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PAGE 28 2023 WINTER EDITION Image Credit: SpaceX
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Image Credit: SpaceX

While the launch of Starship surpassed Elon Musk’s hope of it not blowing up on the pad. It was concerning to see how much destruction the launch pad had suffered. That destruction was caused by the fifteen million odd pounds of pressure produced by the thirty-three raptor engines attached to the Super Heavy Booster. SpaceX has been using a launch pad at Starbase that has a limited water deluge system and no flame trench-deflector.

This is due to the launch pad being built with special heat resistant concrete and being right next to the coast. SpaceX is wanting to reduce the amount of time it takes to prepare the launch pads between launches and was hoping that modern day construction techniques and materials could help them. A flame trench-deflector system is used to deflect the flames away from the rocket to protect it from the heat and energy generated by its engines. The water deluge system also protects the rocket by suppressing the sounds that are created by those engines as well. That way the rocket won’t destroy itself from the incredible sound produced by those same engines which is being reflected off the launch pad.

It was an issue that was discovered during the static test fire of the Super Heavy Booster back in February. SpaceX has said they have been working on a solution that could mitigate this issue four months ago. The solution would involve a massive double layer water cooled steel plate that would cover the launch pad area. It would have kept the launch pad area cool enough during the launch, however it would not have been ready in time and SpaceX thought it was better to get the test launch out of the way before installing that water cooled steel plate.

As the launch pad disintegrated, chunks of concrete were sent out at incredible speeds puncturing key facilities at Starbase. Those chunks were seen reaching heights of around a hundred and fifty metres and reaching distances of over five hundred metres with concrete landing in the Gulf of Mexico.

The dust cloud for the launch started raining down ten kilometres away, ten minutes after launch. Concrete was seen to take out three of the Super Heavy Booster’s engines at the start of the launch, which then caused the destruction of several other engines as the launch progressed. There is also amazing footage of concrete as if fired from a shotgun destroying a photographer’s car and camera gear that was outside the exclusion zone. The camera gear did cost more than the car.

It won’t be so much of a concern for when SpaceX eventually starts launching Starship at Kennedy Space Centre, as the historical launch pad 39A made famous by the Apollo and Shuttle launches, has an installed flame trench-deflector and an extremely powerful water deluge system. It is something that really needs to be sorted out fast at Boca Chica, as Starbase is a spaceport, production, and development facility for Starship, and the testing of Starship is being done from there. That launch pad is eventually going to deal with having to put up with a rocket that’s producing forces equivalent to having two Saturn V rockets strapped together again and again at intervals of days in some cases.

The other major concern that has worried the US Federal Aviation Administration (FAA) was the efficiency of the flight termination system (FTS). The system is intended to break apart the vehicle tanks within seconds during the flight should something go wrong. However, during that maiden launch, this system only punched holes in the tanks and it took forty seconds for Starship to explode.

SpaceX plans to re-certify the FTS system before the next launch, and they have performed a test of that system on a booster test tank at its Massey test facility done the road from Boca Chica. The aftermath of the test does show the complete destruction of the tank on the activation of the FTS which was the desired result, but it’s unclear yet if SpaceX will have to sacrifice further Super Heavy Boosters to more vehicle destruction tests or whether the data from that test will be enough to continue the recertification process through computer modelling.

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Elon and SpaceX have said they are looking to perform another test launch in the next couple of months, but they were only granted one license for that launch by the FAA and as of June 2023, the FAA is still overseeing SpaceX’s investigation of the April 20th launch and explosion.

There is real pressure being placed on SpaceX and the FFA, by officials, environmentalists, Musk haters, and the locals of Boca Chica to do a very long and thorough investigation.

It did take an extremely long time to get that first licence to launch and it could be that it won’t launch until at least 2024, which is very sad as SpaceX’s rapid prototyping philosophy has seen us as a species make huge breakthroughs in rocket technology, and like many industry disruptors before them, they have being able to show us that we can do things that we never thought possible.

Plus, who doesn’t like watching a few rockets experience a rapid unscheduled disassembly.

There will be further speed bumps ahead for SpaceX, they just need to continue to work the problems as they come up and implement the solutions to fix those problems.

The combination of Starship and the Super Heavy Booster not only represents the most powerful launch vehicle ever developed, but it signifies a new era in space exploration. With the capacity to carrying substantial payloads or carry up to 100 people, it will allow us to perform manned missions to destinations such as the Moon, Mars, and beyond, while doing more science than ever.

With the world watching and eagerly awaiting the next stages of the Starship program, the future of space exploration has never looked more promising.

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Image Credit: SpaceX Image Credit: LabPadre via YouTube Image Credit: Patrick T. Fallon / AFP

Sunday Guided Day Tours

Discover the secrets of the universe and the rich history of Perth Observatory on our Sunday guided day tours!

Nestled in the stunning bush settings of Bickley, our Observatory is the perfect place to explore the wonders of the cosmos.

Our knowledgeable guides will take you on a journey through time, from the Observatory’s humble beginnings in 1896 to its move to Bickley in 1966 and beyond. You’ll get to tour the Meridian, Astrograph & Calver Telescopes, learn about timekeeping, and explore the museum to discover fascinating stories about the Observatory’s past and present.

And if the weather permits, you’ll have the opportunity to safely observe the Sun and its sunspots. It’s an experience you won’t want to miss!

With no need to book, simply come up between 1 and 4 pm and pay in our shop. Our Sunday day tours are the perfect way to spend a relaxing afternoon with family and friends, surrounded by the beauty of nature and the mysteries of the universe.

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Celestial Jewellery: Moon Halos Illuminate the Night

There has been some chatter around recently about current sun activity and subsequent aurora phenomena. I’ve al-ways been a bit fascinated by aurora, but I tend to gaze at the sky anytime I’m outside and the other intriguing things I like are Moon Halos. We all tend to take the Moon for granted and most of us hardly give it a second glance. But when atmospheric conditions are right the moon can produce some interesting and rather stunning effects. Scientists call a ring or circle of light around the sun or moon a halo.

A halo (from Greek) also known as a nimbus, ice bow or gloriole is an optical phenomenon produced by light interact-ing with ice crystals suspended in Earth’s atmosphere, resulting in a wide variety of coloured or white rings, arcs, and spots in the sky. Many halos are near the Sun or Moon, but others occur elsewhere or even in the opposite part of the sky. Among the most well-known halo types are the circular halo (properly called the 22° halo), light pillars and sun dogs, but there are many more; some of them common, others (extremely) rare.

Perhaps the most common of these effects are the Moon halos, large rings which circle the moon on a hazy cold night and have a radius of either 22° or 46°. They are more intense when the Moon is at its brightest, around full Moon but can be witnessed to a lesser degree at other bright phases of the Moon. For the rings to appear there needs to be a layer of thin cloud containing millions of tiny ice crystals covering much of the sky high in the upper atmosphere. These ice crystals are typically suspended in cirrus or cirrostratus clouds high (5–10 km) in the upper troposphere, but in cold weather they can also float closer to the ground, in which case they are referred to as diamond dust. Each of these ice crystals behaves like a small lens and because most of these crystals have the same elongated hexagonal shape the moonlight entering one face of the crystal and exiting its opposing face is bent at an angle of 22°. The larger 46° ring which is far less typical may be caused by the light exiting at different angles from the crystals.

A lunar corona is a ring of light, usually in the form of a rainbow, seeming to appear around the moon in the night sky. They are also caused by high thin cloud, but the moonlight is being refracted by water droplets in the clouds and not by ice crystals. On rare occasions Moon Halos and Lunar Coronae can be seen together. The Lunar Coronae have been known to swell or shrink slightly depending on the size of the water droplets that are present in the passing clouds. There can also be colours present on the coronae, but these colours are always very subtle and more likely to be obvious when the Moon is full.

So, the next time you are sitting out under the night sky check it out.

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Image Credit: SHS Photography

Cracking The Ice

Juice’s Quest for Extraterrestrial Life

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Image Credit: Jurik Peter

On the 7th of January 1610, an Italian mathematician pointed his home-made telescope at Jupiter and noticed three bright points of light near the planet. He thought they were background stars, but over a period of days a fourth point appeared and all four kept changing position relative to the planet. Galileo Galilei had discovered the four large moons of Jupiter and correctly deduced that they were in fact orbiting the planet.

Fast forward 413 years and humankind is on its way to the most indepth exploration of those moon ever attempted. From its spaceport on the coast of French Guiana, the European Space Agency (ESA) launched an Ariane 5 rocket carrying JUICE – the Jupiter Icy Moons Explorer. Over eight years, JUICE will traverse the Solar System, arriving in orbit around Jupiter in 2031.

The Moons

Jupiter has many moons – 95 at last count – but four of them stand out in terms of size and mass. These are the Galilean moons –Ganymede, Callisto, Europa, and Io, which are visible from Earth through a pair of binoculars.

The orbits of Io, Europa, and Ganymede form a pattern known as a Laplace resonance; for every four orbits that Io makes around Jupiter, Europa makes exactly two orbits and Ganymede makes exactly one. This resonance causes the gravitational effects of the three large moons to distort their orbits into elliptical shapes… The eccentricity of their orbits causes regular flexing of the three moons’ shapes, with Jupiter’s gravity stretching them out as they approach it and allowing them to spring back to more spherical shapes as they swing away. The friction created by this tidal flexing generates heat in the interior of the moon.

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Io is the innermost of the large moons and at around 3,600 km diameter is about the same size as Earth’s Moon. The gravitational flexing of its shape generates extreme heat in the interior of Io, and consequent volcanic activity has left the surface of the moon peppered with craters and covered with sulphurous deposits. With its volcanic nature and extreme radiation, Io is a most unlikely home for life as we know it.

On the other hand, Europa has long been considered a potential haven for life. Slightly smaller than Io, Europa has an icy surface covered in fissures and ridges. The surface is largely devoid of craters, indicating that the ice layer is constantly being resurfaced. While the inner parts of Europa are thought to be rocky, there is evidence of a sub-surface water ocean up to 100 km deep. Images taken by the Hubble Space Telescope in 2014 and 2016 indicate plumes of water (geysers) up to 100 km high. This combination of liquid water and thermal heating makes Europa an exciting candidate for some form of life.

Ganymede is the largest moon in the Solar System – with a diameter of 5,200km it is larger than the planet Mercury. Ganymede has a magnetosphere (the only moon to have one) which indicates the presence of a liquid iron core. The bulk of the planet is silicate rock and water ice, with the possibility of a substantial sub-surface ocean.

Callisto is the outermost of the Galilean moons, about the same size as Mercury. Callisto is the least dense of the Galilean moons and is composed of equal parts rock and ice. Like Ganymede and Europa, Callisto is thought to have a subsurface ocean. However, Callisto does not share orbital resonance with the other moons and therefore does not have the same amount of internal heating.

The Science

Ever since Galileo’s discovery 413 years ago, astronomers have pondered the nature of Jupiter’s moons. With improving telescopes, we have begun to understand the size of the moons and a little bit about their makeup,

but it’s only by sending space probes that we have gained a more in depth understanding. Starting with Pioneer 10 (launched in 1972), a series of increasingly complex missions have flown past Jupiter, with the Galileo and Juno probes orbiting the planet.

Juice carries many instruments, allowing it to study Jupiter, its atmosphere and magnetosphere. It will study the four major moons and many smaller moons, gaining an insight into the composition of the moons, their surface and internal features, and the presence of subsurface oceans. Detailed mapping of each moon will use visible light, radar, ultraviolet sensors, and other techniques.

Ultimately, Juice will provide data that will allow scientists to determine if any of the moons is in fact a potential haven for life.

The Spacecraft Size and weight

The JUICE spacecraft is a large device with a central cuboid “main bus” to which are attached solar panels and various instrument booms and antennae. Folded up inside the Ariane 5 fairing, JUICE had dimensions of 4.09 x 2.86 x 4.35 m. But when fully deployed, it expanded to 16.8 x 27.1 x 13.7 m.

The dry mass (without fuel) is 2,420kg. The craft carries some 3,650kg of propellant – an unusually large amount for a probe of this type but required for the complex series of orbital manoeuvres planned once it reaches Jupiter.

Main bus

The main body of the spacecraft is roughly cuboidal, and supports the engines, reaction wheels, power supply, computers and science instruments. It is also the point of attachment for the solar panels and instrument booms.

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Image Credit: NASA/ Jet Propulsion Laboratory-Caltech Image Credit: ManuelMata/Alamy Image Credit: Schmidt Ocean Institute
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Image Credit: ESA

Instruments

JUICE carries many instruments to support its science mission. These include magnetometers, radio and plasma wave investigation instruments, and Langmuir probes to analyse the plasma surrounding Jupiter. In addition, there will be cameras, spectroscopes, and a laser altimeter capable of measuring the surface elevation of Ganymede to an accuracy of 10cm.

Perhaps the most exciting instrument is the RIME (Radar for Ice Moons Exploration) ground-penetrating radar, which will search for liquid water under the surface of the moons. RIME uses a 16-metre-long antenna, which was folded down for launch. Unfortunately, unfolding this antenna initially proved problematic but after nearly a month of trying, the antenna has been successfully deployed. The scientific instruments are mounted on the main bus and on four x three metre booms and a 10.6 metre boom.

Power Supply

It takes a lot of energy to keep such a large and complex spacecraft operating in the cold depths of space. Sunlight at Jupiter has only 4% of the intensity of that at Earth. Consequently, JUICE has been equipped with the largest solar panels ever fitted to a planetary probe: ten panels with a total area of 85m2. The panels will generate a total of 850 Watts of electricity – just enough to run a small microwave oven. There is also a large backup battery to keep all systems going when JUICE is behind Jupiter with no access to sunlight.

Communications

To send scientific data and to receive instructions and operating procedures, JUICE has two large communications antennae – a 2.5m high gain dish and a smaller steerable dish. The high gain dish will also act as a heat shield during JUICE’s flypast of Venus. Juice will download more than 2Gb/day, with the deep space tracking station at New Norcia, Western Australia being a key link in the communications chain.

Propulsion and Navigation

Juice carries over 3.6 tonnes of propellant, feeding a main engine developing 425 newtons of thrust. This will provide adequate delta-V for the orbital insertion at Jupiter and manoeuvres around the Jovian system. The main engine uses hypergolic fuel, which ignites spontaneously when exposed to the oxidiser.

Pointing and attitude control will be achieved by a set of reaction wheels – heavy flywheels set on three axes. By spinning up the wheels in turn or causing them to brake, the whole spacecraft can be made to rotate about its centre of mass and point in any desired direction.

The Trajectory

The road to Jupiter is a long one, and spacecraft travelling to that distant planet must fight their way of the Sun and Earth’s gravity wells. A direct trajectory is extremely inefficient, so Juice will follow a complex path around the inner Solar System, swinging past Earth and the Moon, in towards Venus, then back to Earth, and finally onto its final long leg to Jupiter. At each of these flybys Juice will steal momentum from Earth, Moon, and Venus, giving it sufficient kinetic energy to fly out to Jupiter.

The trip to Jupiter, with its many planetary gravity assists, will take eight years, with Juice finally reaching Jupiter in 2031. On the way it will traverse the asteroid belt twice and is scheduled to pass close to asteroid 223 Rosa in 2029.

On arrival at Jupiter, Juice must shed momentum, so that it can enter orbit around the planet and its moons. Initially it will have a highly elliptical orbit around Jupiter, repeatedly firing its engine to slow down and circularise the orbit. This phase will include multiple gravity assists from Ganymede. It will then circle Jupiter, flying by the large inner moons and many smaller ones as well. Eventually, Juice will transfer its orbit from Jupiter to Ganymede, where it will remain forever.

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Image Credit: M. Kornmesser/ESO.

Twinkle, Twinkle, Giant Star Betelgeuse’s Inconstant Brilliance

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Betelgeuse, one of the brightest stars in the night sky, has recently been exhibiting an unusual increase in brightness, leading to speculation it might soon explode in a supernova.

A star that is in its Red Giant phase, it is six hundred and fifty light-years from Earth, and can be found in the left shoulder of the constellation of Orion. It is an enormous star that has burned through all its supply of hydrogen fuel in its core and has expanded hundreds of times beyond its original size. It is now fusing helium into carbon and oxygen, so we know the star’s demise astronomically speaking will happen soon.

Since early April 2023, it has climbed from being the tenth brightest star to the seventh brightest, currently shining at over 140% of its usual brightness. Betelgeuse’s recent antics started back in late 2019, when the “Great Dimming” took place. During the Great Dimming, Betelgeuse unexpectedly dimmed beyond what had ever been seen before. It went from the tenth-brightest star to outside the top twenty bright stars. It was 2.5 times fainter than its at usual dimmest point.

This led some people to start speculating that its death might be near. If Betelgeuse were to go boom, it would be the nearest supernova explosion in more than four hundred years and the first supernova in the Milky Way galaxy since 1604. This had a lot of people hoping to see the spectacular event. The problem is, Betelgeuse is a variable star known for regular changes between brighter and dimmer periods. For more than a hundred years, astronomers have observed Betelgeuse lighten up every four hundred days, then drop to about half of its peak brightness and brighten up again.

The Great Dimming ended up being in an enormous expulsion of material from the star’s interior that created a huge dust cloud that obscured our view of the star.

Betelgeuse has since recovered its usual brightness, but the star has not been its old self since the Great Dimming. Its 400-day brightness period has halved to two hundred days and, on top of that, its continuing to brighten. So, is it dying?

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Image Credit: NASA, ESA, Elizabeth Wheatley (STScI)

The best models’ astronomers have produced, indicate that Betelgeuse still has hundreds of thousands of years left. While Betelgeuse’s regular life has now ended as it has run out of hydrogen, its current helium fusing phase should last hundreds of thousands of years. When that helium fusing phase has finished, it will sustain itself by turning that carbon and oxygen into neon and magnesium giving it another then thousand years. It will then fuse those elements into silicon which takes a further thousands of years, until eventually, the star’s core starts creating iron which in some cases only takes days or hours to happen. This is when the fireworks begin.

When a star’s core becomes completely iron, the end is nigh for the star. This is because the creation of iron in the star’s core requires an endothermic reaction to take place which takes in energy rather than give off energy. Suddenly, rather than a reaction releasing tremendous amounts of energy that does mighty battle with the star’s own gravity so it can exist, the centre of the star starts absorbing energy. At the end, the core of the star collapses on itself and that starts off what we call the core-collapse supernova or a Type II supernova.

Because most astronomers think Betelgeuse is still fusing helium, they were unconcerned by the recent unexpected brightening. The star has been this bright previously, albeit only for brief periods of time. The current thinking from astronomers is that Betelgeuse will return within the next five to 10 years to its usual ways, slowing its cycle of brightening and dimming to the normal four hundred days. Astronomers think the huge bubble of material that was responsible for the Great Dimming in 2019, caused the star’s outer layers and its interior to move in opposite directions, and, as a result, the star is now pulsating twice as fast compared to its normal cycle.

We can make these theories about Betelgeuse due to the star’s size, and position in the Milky Way galaxy. This allows astronomers to study Betelgeuse in better detail than most stars and for longer in our history as well.

We see most stars other than our sun as just points of light, but Betelgeuse is big enough that we can resolve it with the Hubble Space Telescope, and with radio telescopes like the Atacama Large Millimetre/Submillimeter Array (ALMA). Betelgeuse is such an enormous star, if we were to place it at the centre of our solar system, it would extend all the way to Jupiter.

Astronomers can see what is happening in Betelgeuse’s outer layers so well that they can measure the chemical composition of the star’s atmosphere. The images taken reveal a striking body quite unlike our Sun. Rather than a smooth sphere of superhot plasma like our Sun, Betelgeuse is a lumpy clump of boiling gas bubbles. We see huge convection cells of hot material, some as large as a small star, rise from Betelgeuse’s core to its surface, then cool down and disappear back inside its interior. It is like the sun’s cycle but on huge doses of steroids, as the convection cells on the Sun are the size of Texas or Western Australia. We also know once every few centuries, Betelgeuse burps out a bubble of material so large that a Great Dimming ensues.

If Betelgeuse were about to go supernova, we would certainly know it. When it does happen, the star will become as bright as the full moon for around two months. It will be so bright; you would be able to read a book in the light of the supernova on a moonless night and it will be visible in the daylight too. Thankfully, although close to us in astronomical terms, Betelgeuse is too far away from Earth for its explosion to be dangerous to us. Astronomers think that a giant star would have to blow up within 160 light-years from our planet for us to feel the explosion’s effect.

The last known supernova to have exploded in the Milky Way galaxy was SN 1604, also known as the Kepler supernova, named after astronomer Johannes Kepler. According to historical records, it was thirty times more distant than Betelgeuse, and it remained visible during the day for over three weeks.

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From our observations of similar aged galaxies like ours, we are long overdue for a supernova to occur in our galaxy. We should have three supernovas each century, but we are in the middle of an awfully long dry spell that is 419 years and counting.

Betelgeuse has not been visible in the night sky for most of June as the Sun was in the same part of the sky as the constellation of Orion. This means astronomers are having to wait until July when it reappears in the morning sky to check on its progress. Should it continue to brighten, it gives us more of a chance to understand the Red Giant phase of a star’s life.

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Image Credit: ESO/Digitized Sky Survey 2. Acknowledgment: Davide De Martin

Harold Burnham Curlewis and the WA Government’s Celestial Vision

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Stargazing Pioneer:
Image Credit: State Library of Western Australia

There were eight Government Astronomers or Directors of the Perth Observatory, from its foundation in 1896 to when the government ceased operating it as a research facility, in 2015, and entered into an agreement with the Perth Observatory Volunteer Group to run the Observatory as an astronomical outreach and education business.

The most famous Government Astronomer is William Earnest Cooke who led the Observatory from its foundation in 1896 to 1912 when he left to be Government Astronomer at the Sydney Observatory. However, the longest serving Government Astronomer was the man who replaced Cooke, Harold Burnham Curlewis, who was the acting (1912-1920) or appointed (1920-40) Government Astronomer, a period of twentyeight years.

Although he served for the longest time, H.B. Curlewis, probably had the most difficult time of all government astronomers. He didn’t have great support from the government who kept him acting Government Astronomer for 8 years because they were trying to close the Observatory down or have the Commonwealth government or the University of Western Australia take it over. Curlewis also ran the Observatory during the depression of the 1930s for a lot of the time he was on his own.

However, H. B. Curlewis was involved in all the large Perth Observatory achievements in the first part of the 20th century (Astrographic project, seismology, tide forecasting, the keeping and distribution of WST) and his manful striving to improve the quality of the Observatory’s activities are well documented in the Observatory’s archival records along with a good indication of his personality and values.

It is a small coincidence that this article is written in the month that the ShorttSynchronome clocks are being reinstalled in the Observatory Museum following their restoration to working order. There is a whole file in the archives of Curlewis’ efforts in the 1930s to raise the funds to buy the more accurate Shortt-Synchronome clocks to replace the two Kullberg longcase astronomical regulators that had been serving as the Australian Western Standard Time timekeepers since 1900.

When he couldn’t get the funds, Curlewis tried to get the clocks loaned or given to him, but all in vain as funds to replace the Kullberg’s with Shortt-Synchronomes were not forthcoming until the late 1950s for one and the early 1960s for the other.

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Image Credit: State Library of Western Australia

However, this little anecdote is not directly about time, although it plays a very significant part, but about fixing the eastern boundary of Western Australia in the south and the north.

H.B Curlewis

H.B Curlewis was born at Moolal Farm, near Geelong in Victoria in 1874. He began his formal education at Newington College, Stanmore, outside of Sydney. From there he won a bursary to Sydney University where he took a classics degree, studying Greek, Latin, French and Mathematics.

Curlewis was an excellent scholar and sportsman earning a “University Blue” for sporting activities.

In 1898, Curlewis took a position at the Perth Observatory as a computer-observer, where he learned astronomy assisting W. E. Cooke on the Astrograph Telescope. The Chief Assistant to Cooke, H.M Jocelyne, left the Observatory in 1908 to go to the Federal Bureau of Meteorology, and Curlewis assumed Jocelyne’s job as Chief Assistant. In 1912, Cooke left to become Government Astronomer at the Sydney Observatory and Curlewis became Acting Government Astronomer of Perth Observatory.

Fixing the WA Boundary

The boundary between Western Australia, South Australia, and the Northern Territory had been nominally set on the 129th East Meridian, however, no one was sure exactly where that was, nor was it of pressing importance. The ambivalence toward the exact point of the 129th meridian changed in 1918 after the building of the transcontinental railway. There was a desire to know exactly where the rail crossed into WA, and in the north, the cattle station owners living along the boundary, with the WA Government, wanted to know just whether or which part of the stations were in WA.

In 1918, Curlewis wrote to his counterpart in Adelaide, G.F. Dodwell, asking if he would cooperate in determining the 129th meridian.

From then, what had been a straightforward proposition took three years to set on a scheme of action as the parties involved expanded to other state observatories, conferences were held, discussions on how best to get the required accuracy, disputes over funding amounts, and even international cooperation was sought. Eventually the Commonwealth took control of the work plan, and then the Longitude Committee gave the go-ahead in February 1921. An Act was passed by the Commonwealth to legitimise the survey result as the official boundary, even if later more accurate surveys showed it to be in error – after all the wrangling they were not going to have it undone!

There is no doubt that Curlewis believed the work to be highly significant, as he left behind an article justifying the work by citing instances of conflicts over borders from all over the world from ancient Egyptian times up to his present day.

The plan was to build an observing pillar at Deakin on the trans line in the south and as close as possible to the 129th meridian on Argyle station in east Kimberley. The latitude and longitude of each pillar was to be accurately determined, then the position of the 129th meridian in the north and south computed and a line drawn south to north between them.

As Greenwich is zero degrees longitude and the earth rotates 360 degrees in 24 hours, the 129th meridian must be 8 hours 36 minutes from Greenwich. Therefore, the technique for determining longitude in the 1920s, was to determine the time difference between the point of measurement and a station of known longitude. The time difference between two stations can be measured by determining the time when a known star crosses the meridian at each point and as this method is so reliant on accurate time, clocks were set using time signals from various countries.

Being on the trans line Deakin was easy to access consequently its longitude was measured first in May 1921 and determined from a weighted average based on time signals from Bordeaux and Lyons in France,

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the US Naval Academy in Annapolis Maryland, Washington, and Adelaide. The longitude was determined to be 8 hrs, 35 minutes, 62.63 seconds East.

The longitude party from Deakin proceeded to Perth and caught the coastal steamer “Bambera” to Wyndham landing on June 12th where they were met by Hon M. P. Durack the local member. On the 15th of June, the party headed out from Wyndham to Ivanhoe, a distance of 80 kilometres, with all their gear in two cars, one owned by Mr. Durack and the other hired. A correspondent in the party noted that:

“Generally speaking, the track is fairly good for motoring, but over the black boggy country is very bumpy, and diversity is also lent by the numerous creeks that have to be negotiated – occasionally necessitating jumpingoutandpushingthecarsacrossand up the opposite bank.”

A day was spent at Ivanhoe preparing, then the party set off to Argyle Downs 130 kilometres away by wagonette and buggy as the track was now too rough and sandy for motor car. The party arrived on June 20th at the desired spot and set about building the cement pillars for the instruments, erecting the radio masts, and putting up the tents.

When the cement pillars had set, the 12” theodolite of H. B. Curlewis was set on one, and the portable transit of Dadswell on another and observations for time commenced and carried out until the 7th of July. The 12-inch theodolite and the chronometers used to keep time can be seen in the Observatory Museum.

Time signals from Bordeaux, Lyons, and Annapolis were received readily. The times of transmission of these signals were also recorded by observers in Paris, Greenwich, and the Perth and Adelaide Observatories, and a redetermination of the longitude of the Observatories were made.

The longitude for the Argyle station was determined to be 8 hours 36 minutes 5.5. seconds East.

From these fixed points, the 129th meridian was surveyed in.

Postscript

Despite their best efforts, the equipment they were using, and the manual efforts resulted in errors such that the Argyle station was 0.2 seconds west of the true position and Deakin east by 0.1 seconds. This meant that the two markers straddled the 129th meridian 127 metres apart.

The Surveyor General’s corner, where the borders of Western Australia, South Australia, and the Northern Territory meet is marked by two concrete posts, 127 metres apart leading to a step in the boundary – but you won’t see it on any map!

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Image Credit: State Library of Western Australia

Capturing the Cosmos

An Exclusive Interview with Astrophotographer Extraordinaire Michael Goh

LW: Who is Astrophotobear?

MG: There have been times where Astrophotobear has more of a social profile than I do. Everyone knows Astrophotobear - but not Michael Goh. Originally the bear was a presence – a pseudonym - to be avoid an online presence while I was a bank manager.

LW: Did you use a different online handle before @astrophotobear?

Peering into the cosmos through his camera lens, Astrophotographer Michael Goh unveils the enchanting beauty of the night sky in an exclusive interview with our new STEM Outreach Officer Lexie Wallace.

MG: Yes, I had Erax, and I have had that since year 6. Erax used to be a comic character I created. I used to draw comics and sell them. Well, I started selling them as soon as I got to high school, but I was creating characters from year 6 and onwards.

Erax was basically...how that came about was...I could not come up with a name, and I was going through Encyclopedia Britannica, and came up with Erax -- the name of the assassin fly.

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Image Credit: Michael Goh

The character itself was not an assassin fly, but the character was an assassin. That was part of a comic serial I made. I created two volumes of it, and the comic was called Mottob - which is bottom backwards - because of course, when you are young you think, what names can you come up with? I have still got the comics somewhere.

My youngest daughter keeps on asking me to draw characters from there...She is a much better artist than I am. Both of my daughters are very good artists.

LW: Did you draw your comics from photographs, or from imagination?

MG: This was all from my own imagination. In Primary School I was in the advanced class for artists, and you got to do all sorts of extended artwork, like your Indian inks, and some leatherwork. So, I did a lot more of that sort of thing.

Going back a lot further, my mum used to be a teacher before she was a lawyer. She was a teacher when she was in Malaysia, and she’s also an artist. She’s got sculptures that she has done, and she still does a lot of painting now. She’s into a lot of Chinese painting and inks.

LW: Did she have a plan for you growing up?

MG: Law.

LW: Did you think you would become a lawyer growing up?

MG: Well, being Chinese it was, you’re going to be in business, aren’t you? So, my older brother and I both went to business school. I was just floating around, and I suppose that’s the problem with the generation of 40 - 50 plus years or so ago. You could be anything you wanted. I think people ended up with an identity crisis. People thinking, I just don’t know who I am - or what I want to do to contribute.

LW: Did you have an identity crisis?

MG: Well, the thing is that, in high school, I got the top score for accounting and law, and then just naturally went into business...and then just went into working in a bank, and then so many years later you start thinking about, well, what else?

But then at University, I met my wife. And it was quite funny because she was completely off in a different direction as well. She was a social work studentand I was a business school student - and you can’t get much further away from each other.

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Image Credit: Michael Goh Image Credit: Michael Goh

LW: Describe Yourself in three words.

MG: Tired.

Comes with being self-employed. I work a lot longer now, so I need to spend the time to be available and supportive to everyone that matters to me.

Experimental.

Trying different things. I’ve got a new idea, or a client has a new idea - I do a lot of experiments while things are working in the background while I’m still working as well. So, I might have one of the telescope mounts or sliders working away in the background while I’m working on something else as well.

Purposeful.

Even when I’m accepting jobs - I thinkhow does this contribute to why I’m doing everything?

No one says I wish I would have worked more. It’s, how do you live with purpose?

How do you want to have lived?

LW: What’s the first memory that comes to mind when you think of April 20, 2023?

MG: We have a 360° video where you can see us all running around about a minute before totality.

It’s hilarious because not only did we have a huge amount of sunscreen on us, but I’ve quite literally got a thumbprint on the centre of the video, right where the sun is. You clean everything off, but of course it’s greasy and so on...So sunscreen doesn’t work very well.

When I think about the eclipse, I remember it as ...I suppose seeing it at totality with the corona around it. and, for some reason...I know I didn’t imagine it because ultimately everyone else I’ve talked to saw it as well, you can see the pink around it as well. Not sure if it’s something to do with the prominences around the sun. It doesn’t look like a lot of photos that you see of an eclipse.

So therefore, when processing it and so on... it was extremely surreal.

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Image Credit: Michael Goh

I also think of a friend of mine who flew over from Norway, she forgot to remove her solar filter as well. Looking at all the information about how to do the eclipse and so on, when it gets to time to remove the solar filter, usually someone will say, Remove the solar filter! but of course, we were the most experienced people where we ended up going, so no one else was shouting it out.

LW: Did you get a chance to really appreciate the eclipse?

MG: I was more focused on my equipment than I should have because I was running behind schedule. Since the eclipse is only a minute long, one of the main things I thought was important was having pre-sets so you can just literally just turn one knob, instead of having to fiddle around with dials and so on... which itself can take ten seconds or so. For one of the cameras, I had set up, I had not done the pre-sets.

It’s my fault also for having a lot of fun doing the outreach side of things. I had a lot of people coming along seeing what I was photographing. Since I had the footage zoomed in a little bit, almost the entire screen was filled up with the sun. You could see the eclipse coming across, the sunspots that were there, and when it hit totality and so on.

Even with saying that pre-sets were one of the most important things to do with the cameras, I even had two intervalometers attached to the cameras, which were attached to the telescope, so I could quite literally just unplug one intervalometer and plug in another intervalometer without spending time to change what the interval was. So, I went from one shot every second - to one shot every five seconds - for a different phase of how I was doing an eclipse.

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Image Credit: Michael Goh

LW: Where did you set up?

MG: I originally got to the main viewing site before 7, and I was wandering around trying to work out where to set up. I lost close to two hours. I wasn’t technically in the science area, where Matt Woods from the Perth Observatory, the Gravity Discovery Centre, and a few other places were as well. I wasn’t technically in the media area as well, even though I was technically doing it for the media. And it was a few hundred meters from where I parked the car. And I thought, well I’ve quite literally got 20-30 kg worth of gear…and I need to plug myself into power as well, so I thought, well, that’s just not going to work.

So, I drove 500 metres to 1 kilometre away and set up down on a dirt road somewhere. A few of my friends who came over from Norway and Germany turned up to the main site, and said, oh we’re here now -- where are you? And I said, I’ve left. And they quite literally walked to catch up with me.

LW: Your photograph of the eclipse made it to the front page of the West Australian – what were your first thoughts when you saw your image on the front page?

MG: Well, it’s funny, I didn’t see it for a while! I had to ask my eldest daughter to get a couple of the newspapers.

LW: How did your photo make it to the front page?

MG: I have a relationship with ICRAR, and they asked me to send a timelapse through on the day. So originally, I said 3 pm in the afternoon, but I did the timelapse and uploaded it by 12:30 pm when the eclipse was still happening. Because I was shooting tethered, all I did was unplug the camera process what was on there. So, I uploaded the video footage then.

And then, when I was trying to eat some food, I got a message from ICRAR saying by the way, do you have any photos that look

like this? And the photo they showed me was orange. But the eclipse wasn’t orange ...it was white. So, I sent them two photos, and all I did was increase the colour temperature on one.

It was quite literally not much in terms of editing.

LW: Where else did your photo appear?

MG: Apparently, there’s some images of mine from the eclipse that went viral - but sometimes you can’t be sure if it is your photo or not, since you literally have thousands of people photographing the solar eclipse. I know that my image went to multiple television stations here, but it may have also gone to the BBC, because I got a message about that, but I really don’t know. I thought - I’m in the middle of nowhere now - I don’t know what’s going on.

LW: What technical details were behind the image on the front page?

MG: The West Australian image was taken with a Canon 6d on an ED80, using a HDQ5 for the mount. I didn’t use a hydrogen alpha filter.

LW: Are you an eclipse chaser now?

MG: I don’t go outside of Australia much. I want to do more - especially things like a five-minute totality. I am already preparing for the next solar eclipse - the one that goes across the Kimberley in 2028. Hopefully I will be around the Bungle Bungles area, but they said it was going across Uluru, so I am still just trying to work out where to do things.

I’m also working out how to improve things. I’d probably end up having more cameras around - I know I had a crapload around the first time around, but because I had to relocate, I basically was running a little bit behind in my schedule. I had certain intentions, I had quite literally written down intentionally, almost to the second, exactly how things would work out.

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Image Credit: Michael Goh Image Credit: Michael Goh Image Credit: Michael Goh Image Credit: Michael Goh Image Credit: Michael Goh

LW: Why is astrophotography important to you?

MG: As far as my career has gone as a photographer, I try to share the reason why I do things -- as opposed to just making pretty pictures. What is the actual benefit for doing this?

The astrophotography has a positive benefit towards your interest in STEM, towards your arts, towards your mental health - not just my mental health, tourism in the regions, creativity, understanding of aboriginal culture… there’s so many boxes that it ticks, basically. It’s not just about having a pretty photo. But the pretty photo contributes to the creative side of things.

And the environmental aspects of things as well. Not only the light pollution -- but also the other environmental impacts.

LW: Are you involved in any work about light pollution?

MG: Well, yes and no.

The documentary that’s on now about the Square Kilometre Array has a lot of things that’s angled towards light pollution. We were looking at doing a documentary with Astrotourism WA, since they have a very large focus on light pollution as well. But I’m working on formulating effectively a documentary myself on light pollution anyway.

There are other documentaries and things that are being done about light pollution, but in terms of promoting our night sky conversation, there’s nothing stopping us from saying, - let’s just get something done to create something that highlights the issues of how fantastic the night sky is, and why it needs to be preserved, and the effects of light pollution itself.

Unless people learn about more it, they won’t really care. A part of this is also working on virtual reality as well.

I effectively have people interested in what I do, but it’s just if you can tell the write stories with it. Everything is about storytelling when you’re placing it to various places, so it’s about how do you want to portray something, you don’t want it to purely be about pretty images, and so on. It’s about asking: what is the actual benefit of doing this?

LW: If you were to capture your personality in a single photograph, what would it be?

MG: It would be me sleeping on the back of a truck.

LW: What advice would you give to aspiring photographers who are just starting their journey?

MG: Well, I always think it’s funny, I run workshops, and one of the first things I say is: Don’t listen to anything I’m talking about. Because, I mean, when I started doing astrophotography, everything was very formulaic: don’t go above ISO 1600; have the widest aperture - f2.8; follow the rule of 500, or whatever. I always used to laugh, because I got asked by a photography magazine to write an article about the rule of 500, and I said, ‘I don’t believe in it,’ but I still wrote about it.

Ultimately: Just experiment. Push yourself until you’re uncomfortable, with things like your astrophotography. Do a lot of research… although you don’t need to do research either. You can just do whatever you want.

I remember one piece of feedback I got earlier on, with an astrophotography image, was ‘you’d get lose noise if you had a shorter shutter speed and shot with a lower ISO’and I thought, well you have no idea what astrophotography is about.

I’m not actually a fake-it-until-you-make-it sort of person. I’m just an experiment, test, and push yourself until you’re uncomfortable.

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If you’re going out to shoot the night sky, have an idea of something that you wouldn’t normally do as well, so you can push yourself a bit further. Then look at it again later and think, what can I play around with next time to improve?

When I started doing multi-row panoramas, I also remember people saying, you can’t start doing ultra-wide multi-row panoramas! But everyone does multi-row Astro panoramas nowadays as well. Regarding just photography itselfit’s just, keep on practicing, and just shoot things.

I used to have a bit of philosophy as well to try as many things as possible, because you don’t know when something will be useful. I use flash photography for my astrophotography as well -- like in my selfies, for example. I know a lot more about lighting because I shoot other things, not just the astrophotography side of things. That also then leads into knowing more. I also use things like high noise exposures in normal photography. Everything is interchangeable.

You’re just pushing your boundaries and experimenting. Things can be used all over the place. It’s just, try something different, and experiment. Push your boundaries a lot.

LW: What’s something readers can look out for?

MG: I am working on some projects, but I’m still going through what goes into it. I have a lot of video sort of projects. My idea this year is hopefully to get about 100 timelapses done or so, but I’m still a bit behind schedule. There’s always factors that come into the equation, you’ve got to be a bit flexible about things.

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Image Credit: Michael Goh

What’s In July’s Skies

Planets:

Mercury will make its reappearance in the second week of July, appearing very low on the western horizon. It will begin the week situated in the constellation of Cancer (The Crab), but as the month progresses, it will transition into the constellation of Leo (The Lion), drawing nearer to Venus, and the star Regulus. Venus can be observed in close proximity to Mars, positioned low in the constellation of Leo until the middle of the month when they gradually separate in the night sky. Meanwhile, Mars will continue its journey through the constellation of Leo, reaching its hind feet by the end of July.

Jupiter can be located between the head of the constellation of Cetus (The Sea Monster) and the front feet of the constellation of Aries (The Ram) during night-time. Saturn is also visible in the middle of the constellation of Aquarius (The Water-Bearer) in the night sky. Uranus rises late at night within the constellations of Taurus (The Bull), precisely positioned between Jupiter and the Pleiades Cluster. Lastly, Neptune can be found during the early night-time hours, situated between the top fish in the constellation of Pisces (The Fish) and the tail of the constellation of Cetus.

Astronomical Events This Month:

The Delta Aquarids Meteor Shower:

The Delta Aquarids meteor shower is set to reach its peak on the night of July 30th/31st, primarily favouring observers in the southern hemisphere, including those in Perth. This captivating shower remains active from the 12th of July to the 23rd of August, with the number of meteors seen per hour varying between 10 to 20. However, in 2023, the presence of a Full Moon in the night sky will result in reduced visibility of meteors from this shower.

The radiant point for the Delta Aquarids lies within the constellation of Aquarius, becoming visible from 08:00 pm (AWST) on the 30th of July. For optimal viewing, it’s best to wait until 03:00 am (AWST) on the 1st of August. The Delta Aquarids lack a prominent peak, but they consistently grace the night sky with their presence throughout their active period. It is believed comet 96P/ Machholz 1, once part of the Kreutz Sungrazing comets, is the source for the Delta Aquariids.

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Jupiter, Saturn, Uranus, and Neptune on the 15/07/23 at 05:30 am. Image Credit: Stellarium Mercury, Venus, and Mars on the 15/07/23 at 06:30 pm. Image Credit: Stellarium

Things To Look At This Month: Butterfly Cluster:

The Butterfly Cluster, also referred to as Messier 6 (M6) and NGC 6405, is an open cluster comprised of approximately 120 stars located within the constellation of Scorpius (The Scorpion). Positioned around 1,600 light-years away from Earth, the stars within this cluster are estimated to be between 55 and 100 million years old. Visually, the Butterfly Cluster appears slightly smaller than a Full Moon, with dimensions measuring 12 light-years in width and 25 light-years in length. It is crucial to avoid confusing M6 with its brighter neighbour, Ptolemy’s Cluster (M7), situated southeast of it.

While the discovery of the Butterfly Cluster by Giovanni Hodierna predates 1654, his data was not unearthed until the 1980s. It was independently discovered by Philippe de Chesaeux in 1745/6, and Messier catalogued it as M6 in 1764. Remarkably, the Butterfly Cluster remains one of the few objects within the Messier Catalogue yet to be photographed by the Hubble

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Space Telescope. The Delta Aquarids on the 28/07/23 at 05:00 am. Image Credit: Stellarium A meteor from the Delta Aquarids. Image Credit: David S. Brown The Butterfly Cluster on the 15/07/23 at 09:00 pm. Image Credit: Stellarium

Messier 6 Butterfly Cluster

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Image Credit: Nicolas Rolland

What’s In August’s Skies

Planets:

At the beginning of the month, Mercury, Venus, and Mars can be spotted low in the western evening sky within the constellation of Leo (The Lion). Throughout August, Mercury will remain in Leo, closely interacting with Mars in the middle of the month. On Monday, August 10th, Mercury will reach its greatest elongation in the East before gradually returning towards the Sun. On the other hand, Venus will only be visible during the first week of August before becoming obscured by the Sun’s glare. It will remerge in the morning sky in the middle of August, positioning itself between the constellations of Cancer (The Crab) and Hydra (The Serpent). Mars, initially located in Leo, will transition into the constellation of Virgo (The Virgin) around the middle of August.

Jupiter can be found in the night sky positioned between the head of the constellation of Cetus (The Sea Monster) and the front feet of the constellation of Aries (The Ram). Meanwhile, Saturn can also be observed in the middle of the constellation of Aquarius (The Water-Bearer).

Uranus rises late at night within the constellations of Taurus, situated prominently between Jupiter and the Pleiades Cluster. Lastly, Neptune can be located during the early night-time hours, positioned between the top fish in the constellation of Pisces and the tail of the constellation of Cetus.

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Jupiter, Saturn, Uranus and Neptune on the 15/08/23 at 05:00 am. Image Credit: Stellarium Mercury, Venus, and Mars on the 15/08/23 at 06:30 pm. Image Credit: Stellarium Mercury’s greatest elongation in the East on the evening of the 10/08/2023. Image Credit: Stellarium Alignment of The Moon, Mercury, and Venus on the 19/08/23 at 07:00 pm. Image Credit: Stellarium

Astronomical Events This Month:

The Perseids Meteor Shower:

The eagerly anticipated Perseids meteor shower is nearly upon us, reaching its peak on the night of the 13th/14th of August. This captivating display is primarily visible in the Northern Hemisphere and takes its name from the constellation of Perseus (The slayer of Medusa and the rescuer of Andromeda), the apparent source of these meteors. The Perseids shower remains active from mid-July to the end of August.

Observers in the Northern Hemisphere can typically witness a meteor rate exceeding 100 meteors per hour during the peak night. However, for those of us in Australia, the chances of observing the Perseids are limited to the northern part of the country. To catch a glimpse, one must venture out around 5 am when the meteors will appear very low on the horizon in the northern direction.

Fortunately, this year’s viewing experience will be favourable, as a Waxing Crescent Moon graces the eastern sky during the optimal viewing time. While there will be a slight amount of light pollution from the Moon, it will not significantly hinder the enjoyment of the meteor shower.

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The Perseids on the 13/09/23 at 05:30 am. Image Credit: Stellarium The Perseids meteor shower over a lake. Image Credit: Getty

Things To Look At This Month:

Cat’s Paw Nebula:

For the Astrophotographers out there, let’s explore the fascinating Cat’s Paw Nebula (NGC 6334), an emission nebula and star-forming region nestled within the constellation of Scorpius (The Scorpion). Also known as the Bear Claw Nebula, it was initially discovered by astronomer John Herschel in 1837 during his observations from the Cape of Good Hope in South Africa. This nebula finds its place in the Carina–Sagittarius Arm of the Milky Way, located approximately 5,500 light-years away from Earth.

Spanning an impressive 320 light-years, the Cat’s Paw Nebula captivates observers with its vivid display. In the visible spectrum, it predominantly emits a striking red hue from ionized hydrogen atoms, while bursts of blue originate from oxygen atoms.

Encompassing an area in the night sky slightly larger than the full Moon, this nebula boasts numerous star-forming regions that have been identified through infrared and radio emissions. It stands as one of the most active stellar nurseries, birthing massive stars within the Milky Way Galaxy. The nebula owes its radiant glow to the presence of hot, young stars deeply embedded within its core. Some of these celestial giants exceed ten times the mass of our Sun and have emerged within the past few million years, perpetuating the ongoing cycle of stellar birth and evolution within this cosmic marvel.

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The Cat’s Paw Nebula on the 15/08/23 at 09:00 pm. Image Credit: Stellarium

NGC 6334

Cat’s Paw Nebula

Image Credit: Stefan Steve Bemmerl & Team Wolfatorium
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What’s In September’s Skies

Planets:

In the upcoming month, there are some celestial movements worth noting. Mercury will gradually disappear from our view, getting lost in the Sun’s brilliance during the first few days of September. However, it will make a reappearance in the eastern morning sky around midSeptember, still situated within the constellation of Leo (The Lion). Keep an eye out for Mercury’s greatest elongation in the West on Monday, September 22nd, before it retreats towards the Sun.

As for Venus, it will commence September positioned between the constellations of Cancer (The Crab) and Hydra (The Serpent). By the month’s end, it will have journeyed to the front paws of the constellation Leo. Mars, on the other hand, will be making its way through the constellation of Virgo (The Virgin) throughout the entire month of September. To catch a glimpse of Mars, direct your gaze low in the western sky during the early evening hours.

Shifting our attention to the giant planets, Jupiter can be found nestled between the head of the constellation Cetus (The Sea Monster) and the feet of the constellation Aries (The Ram) in the night sky. Saturn, another magnificent sight, will grace the middle of the constellation of Aquarius (The Water-Bearer).

For those interested in spotting Uranus, it will rise late at night within the constellations of Taurus, precisely situated between Jupiter and the Pleiades Cluster. Lastly, Neptune can be observed during the early night hours positioned amidst the top fish in the constellation Pisces (The Fish) and the tail of Cetus.

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Venus, Jupiter, Saturn, Uranus and Neptune on the 15/09/23 at 05:00 am. Image Credit: Stellarium Mars on the 15/09/23 at 07:00 pm. Image Credit: Stellarium

Astronomical Events This Month:

Zodiacal Light Season Begins:

Get ready for the start of the Zodiacal Light season, commencing on the 1st of September. This amazing phenomenon occurs as the Sun approaches the September Equinox, which falls on September 23rd. At this time, sunlight scatters off dust particles dispersed along the ecliptic plane—the apparent path of the Sun’s motion on the celestial sphere as observed from Earth.

The best opportunities to witness this enchanting pearly glow are during the spring and autumn seasons, particularly at dawn or dusk. This is because the steep angle of the ecliptic in relation to our horizon allows for optimal visibility. In the Southern Hemisphere, dusk is favoured during the September Equinox season, while in the Northern Hemisphere, it’s dawn. The opposite holds true near the March Equinox.

To catch a glimpse of the zodiacal light, venture out approximately an hour after sunset or an hour before dawn. Choose a location with minimal light pollution, aiming for a dark site. Any interference from nearby cities or faint glows on the horizon can diminish the ethereal radiance of the zodiacal light. As you observe, you’ll notice a slender pyramid-shaped glow tracing the length of the ecliptic plane, creating a truly captivating display.

The September Equinox:

Equinoxes and Solstices.

Image Copyright: timeanddate.com

On Saturday the 23rd of September at 02:49 pm (AWST), the Southward Equinox - an astronomical event that signifies the onset of fall in the Northern Hemisphere and the arrival of spring in the Southern Hemisphere will occur. At this moment, the Sun’s declination, as observed from Earth, reaches 0°. The equinoctial points, where the celestial equator intersects with the imaginary path of the Sun known as the ecliptic, defines this significant occurrence. Throughout the 21st century, the September Equinox will fall on either September 22nd or 23rd, until the year 2092 when it will occur on September 21st every fourth year.

The term “Equinox” originates from Latin and translates to “equal nights.” During this event, day and night are nearly equal in duration across the globe, and the Sun rises precisely due east and sets due west as seen by an observer. The Full Moon nearest to the September Equinox holds the title of the “Harvest Moon”, a period when farmers utilise the extended twilight to gather their crops. In 2023, the Harvest Moon will grace the sky on the 29th of September.

It’s worth noting the term “Equilux”, which distinguishes the true Equinox from the point when the duration of daylight matches the duration of night-time. Several factors contribute to this disparity, including the time it takes for the physical diameter of the Sun to clear the horizon, atmospheric refraction, and the observer’s precise location within their respective time zone. The Equilux occurs within a few days of either Equinox, accounting for these variations.

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The Zodiacal Light at Lake Poorrarecup. Image Credit: Matt Woods

Things To Look At This Month:

Helix Nebula:

The Helix Nebula, also known as NGC 7293, located in the constellation of Aquarius, is a mesmerising planetary nebula. Among the closest planetary nebulas to Earth at a distance of approximately 655 light-years, it shares a striking resemblance in appearance to nebulas such as the Cat’s Eye Nebula and the Ring Nebula. These nebulas possess similar size, age, and physical characteristics, akin to the Dumbbell Nebula. In popular culture, it has been likened to the “Eye of Sauron” or the “Eye of God”.

Unlike the star-forming regions found in nebulae like The Orion Nebula (M42), a planetary nebula marks the late stage in the life cycle of a star. It occurs when a star expels a shell of material in a nova-style explosion. The intense ultraviolet radiation from the progenitor White Dwarf star causes the previously expelled shell of gas to fluoresce brilliantly, creating an emission nebula. From our perspective, the gases expelled from the star give the impression of a helix structure, as if we are peering down its winding path. Spanning a modest 2.5 light-years, the expansion of the entire planetary nebula is estimated to have commenced around 6,560 years ago.

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The Helix Nebula on the 15/09/23 at 09:00 pm. Image Credit: Stellarium

NGC 7293

Helix Nebula

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Image Credit: Trevor Jones

Star Adoption Tours

Looking for a unique gift to recognize a special family member or friend? Look no further than our star adoption program! Our program allows you to adopt a star between magnitudes -1 and 7.9 in the Southern Hemisphere, visible to the naked eye or in binoculars.

Each star adoption package includes a certificate with the star’s name and coordinates, as well as the duration and purpose of the adoption. Plus, you and up to three guests can enjoy a private star viewing night within 12 months of the adoption, where you’ll get to see your chosen star and other seasonal objects. We’ll also provide you with a planisphere and star charts, so you can continue to enjoy your star long after your viewing night.

Please note that while we don’t offer international naming rights for stars, the income from our program goes towards supporting the Perth Observatory’s not-for-profit public outreach program. Adopt a star today and give the gift of wonder and discovery!

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Perth Observatory Night Cameras

Perth Observatory is a member of the Global Meteor Network, and we now seven cameras recording the night sky. These state-of-the-art cameras capture meteors, satellite passes, and other celestial events, providing us with a unique view of the Solar System’s formation and evolution.

The footage captured by these cameras is not only valuable for scientific research but also for public viewing. You can now watch live images from the camerasat night, which update every three minutes during the night. Additionally, we’ve made available condensed footage from the previous night, highlighting every meteor detection. Be warned, it’s hard not to get hooked on watching these videos.

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A Quick Look In The Astroshop!

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CONTAINERS FOR CHANGE

Help Perth Observatory through the Containers for Change scheme.

Please take glass, plastic, aluminium, steel, and paper-based cartons between 150mL and 3L to your local refund depot and use the Perth Observatory (Scheme ID: C10424615).

The Perth Observatory Volunteer Group will receive 10 cents for each container. Save the ID on your phone for every time you recycle your containers. Find your local refund depot and get more info on what containers are eligible for refunds here:

containersforchange.com.au/wa

Can’t get to a refund centre? We have a dedicated and labelled bin on-site for you to add your clean container donations when you next visit the observatory.

Our maintenance volunteers collect donated containers and takes them to the refund centre.

Thank you for helping the POVG promote sustainable and environmentally conscious practices and diversifying ways for us to raise much-needed funds.

Your help supports the continuing upkeep and running of Western Australia’s oldest observatory!

SUPPORT PERTH OBSERVATORY
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The Funny Side

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Contact Us Perth Observatory 337 Walnut Road 6076 Bickley, WA (08) 9293 8255 newsletter@povg.org.au perthobservatory.com.au

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