It all started innocently enough…..
The Orion Nebula, light from this takes over a 1000 years to reach us and is an obvious beginner target as it is large, bright, easy to find, can be captured with relatively simple gear and is unbelievably spectacular.
After chasing images comet Leonard over the Christmas break I started thinking about all those other things in the night sky I had heard about. I love shooting the Milky Way, combining it with landscapes to get images that I love, but there are a lot of smaller and dimmer objects in the night sky that with just a little more effort can provide you with absolutely amazing images. So I gave up sleep, friends, my savings and the last remnants of my sanity and started down the ridiculously deep rabbit hole that they call deep sky astrophotography.
This blog is definitely not going to be a how to class, there are a huge number of excellent YouTube videos that give great information on the topic, I now I have watched enough of them to melt my brain. If you are interested in a play list of ones I would recommend just drop me a line.
Rather this is just a quick overview of the evolution of the gear that I have used and am using currently. I say currently because the hunt for deep sky objects definitely leaves you wanting more. The gear you use is not particularly any more expensive than the good quality regular camera gear, often cheaper. It is just way more specialised. Anyway, hopefully this blog will go someway to answering the questions I get whenever I post an image like the one above on social media.
My original rig for trying to capture the deep sky (and the comet). Essentially what I use for Milky Way landscape images, just swapping out my wide angle lens for a 100- 400 mm zoom. Using this alone, in a decently dark sky site, is enough to capture a great image of Orion. Ioptron Skyguider, Canon R5 and ef100-400mm zoom.
Using the basic setup above, a star tracker and a decently long lens, you can get nice images of Orion and some of the other bright objects (it is pretty cool the first time you point a long lens at Jupiter and see its moons, bit tiny to photograph, but still one of those moments). You need to do image stacking to get rid of noise and light pollution is a total pain so travelling to dark sky sites helps, but you can get nice images.
However a simple star tracker like the above really struggles by itself to get longer exposures when with long lenses without star trails becoming evident. So the first upgrade is to improve this by adding what is called a guiding camera. This is a second small camera hooked to a computer and telescope that tracks stars and makes tiny adjustments to the tracking to make up for errors in the equipment and polar alignment. Using this kind of set up makes exposures of over two minutes (some people can get 4 or 5 minutes) possible with the above gear. These longer exposures are what you need when trying to collect the relatively scarce photons that have traveled 8000 light years or more from something like the Carina Nebula to our insignificant part of the our galaxy.
The addition of a guiding camera and computer can massively increase the length of the exposures you can take, and also has the advantage of making polar alignment way easier. Here I am using a dedicated astro computer in the little red box on the tripod leg, but any windows laptop will do the job.
You still need to collect lots of images and stack them. You also need to learn about calibration frames that you take as well to compensate for sensor noice, thermal noise and the imperfections of your optical system (Milky Way landscapes are definitely easier). Once set up, however, this gear can take really amazing images of deep sky objects, especially from dark sky locations.
So did I stop here, as any sensible and reasonably sane person would, no. Being the kind of person I am I began to get frustrated by things like:
the thermal noise generated by my R5 sensor (starting this process in a South Australian summer where overnight temperatures can tay above 30 degC occasionally was probably not that bright),
the imperfections in my lenses which while excellent for my daytime photography were not quite as satisfying when everything you are imaging is a point source of light
and the actual frustration of finding small faint objects in the night sky (the sky turns out to be a very very big place when you are looking through a 400 mm lens).
So began the mind melting process of going blind watching YouTube videos, reading huge numbers of forums and blogs and searching for second hand gear or great deals (and borrowing some thing from generous friends). All to set up a basic astro rig for semi deep sky objects.
My current astro set up, goto mount (Ioptron CEM26), 250mm f4.9 telescope (redcat51), cooled colour camera (ASI183mc pro), guide camera and scope and dedicated astronomy computer (ASIAir plus). Is this going to be the end of this process, well…….
Firstly I obtained a goto mount. These amazing pieces of gear not only track the movement of the stars, but using either the hand controller or an attached computer, will point your telescope directly at the object of interest and then stay locked onto it as the earth moves under the sky (really useful for someone as impatient as me).
Next was a dedicated astro camera. This is essentially a small digital sensor with a massive cooling unit attached to the back of it. No LCD screen, or controls either for that matter, all managed by a seperate computer. However it can cool itself down to -10 deg C or less on a warm summers night and is designed to put things like light pollution filters between it and the lens. Totally useless for my next landscape or product shoot, but it does give amazing low noise images when collecting images of the the night sky.
Then there is the telescope / lens (it says on the box that it can be used for normal photography, not going to replace my canon L glass any time soon). A 250 mm fixed 4.9 aperture telescope with amazingly clear optics. Actually less reach than my 400mm, but given that the camera sensor is much smaller than full frame it works out about the same.
Finally round it out with the guide camera and scope that I had acquired before and a dedicated mini computer that manages all these items and can be controlled from my iPad or phone (I hate cables and windows laptops) and I could really start acquiring data (the astro community talks about data and not photos it seems, probably to make it sound more scientific and justify those long nights alone :-) ).
Eta Carina, over 8000 light years away but huge in our souther sky. One of those red patches we often see in Milky ways shots. Mind blowing when you first see it come up on your computer as you take the images.
Is this all there is to taking deep sky astro images, not by a long shot. The post processing when you are collecting 10’s if not 100’s of images to make up the single final image is another whole learning experience. But I may save that for another blog if anyone is interested.
Is this the end of my equipment hunt for this particular area of photography…. probably not.