FORMATT HITECH AMBASSADOR FOCUS
Photographing Deep Space Objects
Formatt Hitech Official Ambassador, Duncan Arnold
Ever since my interest in photography began, it has always
space objects will be much less than what you may be able to
been pictures of the night sky that have been my biggest
achieve with other styles of photography. That said however,
source of inspiration. I can remember countless times
when everything comes together, it is often quite a surprise as
throughout life where I have often found myself staring up at
to what you can achieve without having to use a telescope.
the stars and I am sure that each and every one of us at some point have found themselves doing the exact same thing.
The image above is an example of what you can expect to take with any reasonably modern DSLR or mirrorless camera,
For me, it induces an overwhelming sense of the unknown.
a telephoto lens and a star tracker. The subject is the Orion
What else exists out there, where and how did it all begin? I
and Running Man nebula within the constellation of Orion. It
still find it incredible to think that each time we look up to the
was taken with a Canon 6d (released in November 2012), a
night sky, the light from the stars that we see ranges from
Canon 100-400mm F4-5.6 Mk 1 lens (released in September
a few years old to a few thousand years old. Polaris or the
1998) and most importantly the SkyWatcher Star Adventurer
North Star for example is 680 light years away from Earth, so
star tracker which has also been around now for a good
the light that we see from it is actually 680 years old!
number of years.
Photographing deep space objects is quite a challenging
So, you may now be asking yourself what is a star tracker
and complex process. It requires some specialist equipment
and why is it so important when photographing deep
and software, a lot of patience and, most importantly, nights
space objects? Well, this is where it gets a little bit more
without cloud. Further to this, depending on your chosen
complicated, but bear with me while I try and explain.
subject, you may also require a particular moon phase and even a particular time of the year where a specific area of the
Planet Earth rotates, this rotation, along with the focal
sky or constellation is in view within your hemisphere. As
length you are shooting at, will dictate the maximum shutter
such, your ability to produce portfolio quality images of deep
speed you can set before stars start to trail. A star tracker is
designed to move your camera at the same speed as Earth rotation so this allows us to use much longer shutter speeds to obtain a correct exposure without any visible star trailing. It also has the benefit of allowing us to reduce our ISO and perhaps even shoot at a narrower aperture to obtain better optical quality images. For the example image of the Orion and Running Man nebula, the focal length was 400mm, without using a star tracker the maximum shutter speed would have been limited to one second only, nowhere near long enough to capture enough light for a correct exposure. By using the star tracker, I was able to obtain a shutter speed of 90 seconds at ISO800 and an aperture of f/5.6. Setting up your equipment to shoot a deep space object is also not a straight forward process, the star tracker needs to be completely level so you will need to adjust your tripod accordingly and you will also need to polar align the star tracker. Polar alignment involves lining your star tracker up with the north star (Polaris), the more accurate your polar alignment is, the longer shutter speeds you will be able to achieve. Once polar aligned, you will then need to point your camera at your chosen subject, ensure that you correctly focus your lens, and take test images to see how long a
Locating the deep space object Duncan photographed
shutter speed you can take before the stars start to trail. This setup process once practiced a few times will take on average
taken more light and dark frames but on the particular night
10 – 15 minutes.
I took these images I only had a brief window before cloud moved in. I would have preferred to have had at least 30
To get the best results when shooting deep space objects,
light frames and 15 dark frames. The image below is the TIFF
you will also need to take multiple images and use an
file created within Sequator prior to further processing and
advanced processing technique often referred to as image
cropping within Photoshop:
stacking. Image stacking involves taking multiple images and then using specialist software to stack them, this will
Stacking the images, you will be pleased to hear is a relatively
increase the detail and reduce noise and hot pixels within the
straight forward process. I use a software program called
final processed image. You may have seen people referring
Sequator, there are many other alternatives out there such
to light, dark, bias and flat frames, personally I only use light
as Deep Sky Stacker and PixInsight but I find Sequator the
and dark frames and am happy with the results that this gives.
easiest and fastest to use. You simply load your light and
Light frames are essentially the images that you take of your
dark frames in to the application, set your output location,
chosen subject. Dark frames are images taken with the exact
set the Composition options to align stars and accumulation,
same shutter speed, ISO and aperture values as your light
set the colour space to Adobe RGB and click start. A few
frames but with the lens cover attached. The dark frames are
seconds or minutes later depending on the speed of your
used to identify noise and hot pixels which the software then
computer, Sequator will create a stacked image file in TIFF
removes from the light frames. The more images you take
format. Once complete you can then load this into Photoshop
and stack, the better the resulting image should be.
to complete the processing of the final image with colour balance, cropping and resizing.
In the example image of the Orion and Running Man nebula, I took 15 light frames at 90 seconds each and 8 dark frames
Living on the edge of a small town that is continually
also at 90 seconds each. Therefore, the total exposure time
expanding with new housing developments popping up all the
of all of the light frames was 22 minutes and 30 seconds and
time, light pollution is becoming an ever-increasing problem
for the dark frames a further 12 minutes. Ideally, I would have
for us all. Whilst the effect of light pollution can be removed
reasonably well during post processing, it is time consuming and can often alter the overall colour balance of the final image. When photographing deep space objects, I usually travel several miles outside of town to the North Norfolk coast to escape light pollution. Having recently been selected as a brand ambassador for Formatt-Hitech, I was keen to test the Firecrest Nightscape filter for photographing deep space objects and I am more than happy with the results achieved. It did an excellent job of removing light pollution and allowed me the luxury of setting up and shooting from the comfort of my back garden, so once everything is set up, I can now go back indoors into the warmth and have a cuppa whilst leaving the star tracker and camera to do its thing, perfect! Finally, the observant amongst you may have noticed a few other accessories in the image of the star tracker and camera setup. These are: 1. The Formatt-Hitech 100mm filter holder system. 2. The recently released Firecrest Nightscape filter which has been specifically designed to reduce the effect of light pollution. 3. A Through the Lens Workshops lens heater connected
Duncan’s Astrophotography Setup
to a USB powerpack, designed to prevent the build-up of condensation on the lens element and Nightscape filter. 4. Wireless remote intervalometer for setting up continuous shooting of the 90 second exposures with the camera in bulb mode. If you would like to learn more about photographing the night sky, why not take a look at one of the workshops I run at throughthelensworkshops.co.uk. While these are currently held in Norfolk, we are looking to bring them to other parts of the country in the near future where you will also be able to try out the Formatt-Hitech Nightscape filter for yourself.
The Formatt Hitech Firecrest Nightscape Filter
Duncan is currently employed as an IT security specialist, but his passion for photography means the majority of his spare time is spent on one aspect of his craft or another. He is a member of Formatt Hitech team and runs workshops with fellow ambassador Dibs McCallum. Find Duncan online at facebook.com/focusbug and focusbug.co.uk For workshops, visit throughthelensworkshops.co.uk
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