In astronomy, deep sky objects are those which are very far away from our planet. Deep sky photography, therefore, involves the capture of distant galaxies, nebulae and other astrophotgraphy targets. There are literally thousands of these deep sky objects available to anyone with the necessary equipment and in my experience, this kind of photography is challenging, exciting and filled with many technical issues to overcome along the way.
So, if you’re interested in how to take amazing pictures of space, or if you are looking for information on how to get started in astrophotgraphy, I’ve got a lot of helpful information for you here.
Before we get started though, let’s outline exactly what deep sky photography is and what challenges it provides:
Deep-sky photography targets objects which are many light-years distant. They can be seen in telescopes but are very faint. When photographed, nebulae, star clusters and galaxies reveal their beauty, structure, and color. Deep-sky photography requires a telescope, camera, mount to track the stars, and software to process the images.
The universe is a beautiful place. It’s full of stars, planets, and other celestial bodies. But it’s also full of mysteries that we’re still trying to figure out.
We’ve been looking up at the sky for centuries, but only in the last few decades have we been able to explore space with satellites and telescopes. And now, thanks to advances in technology, you can take amazing photos of space from your own backyard!
Here are some thoughts on the best telescope to use for astrophotography.
A Few Examples Of My Deep Sky Photography
Since I started astrophotography in summer 2020 I have managed to capture many images of deep sky targets and here are some of my favourite photgraphs that I’ve taken so far in less than two years from entering this hobby as a beginner.
The Horsehead and Flame Nebula in Orion
The Horsehead Nebula is stunning isn’t it? It may be one of my favourite deep sky objects to photograph in the night sky. It is only possible to photgraph this during periods when Orion is in the night sky. In the Northern Hemisphere this is during Winter and Spring. The Horsehead Nebula is also referred to as Barnard 33 and lies about 1500 light years away from us. This means that although I took the above photograph in 2021, you are seeing how it looked 1500 years ago (ie. in approximately AD. 521!)
I took this image during the longer nights of winter under a Bortle 5 sky using a Canon 600D DSLR camera modified for astrophotgraphy. To modify a DSLR for astrophotgraphy the filters in front of the sensor are removed to allow mre hydrogen alpha signal through which is necessary for higher quality astrophotos.
I also used my Celestron 130slt reflector telescope on an equatorial mount, the ioptron CEM26. This allowed me to track the object and take images each of three minutes exposure. For this target I combined the following:
61 x 3 minute RGB images at ISO 800 with SVBONY CLS filter.
53 x 3 minute Hydrogen Alpha at ISO 800 with Astronomik 12nm HA filter.
The RGB and HA images were stacked using Sequator to create a HA image and an RGB image which were combined and processed in Photoshop.
If you are interested in the workflow and method I followed for processing a HARGB image, please watch this video by Tadej Skofic.
What are the Best Cameras for Deep Sky Photography?
The best cameras for deep sky photography are those that can capture the most light. This is because the stars in the sky are so far away that they appear as tiny points of light. The more light a camera can capture, the more detail it will be able to show in these stars.
Generally, there are two kinds of cameras used for deep sky photography, DSLRs and dedicated astronomy cameras. I am currently using a Canon 600D DSLR.
What are the Best Lenses for Deep Sky Photography?
The best lenses for deep sky photography are those that have a wide aperture. This is because the wider the aperture, the more light can enter the lens and reach the sensor. The more light that reaches the sensor, the better your image will be. Each lens will give you an F number, for example, one of the lenses I use is the Samyang 135mm and is F 2.0 at its maximum setting.
How to Choose the Right Mounting System for Your Telescope?
Mounting systems are the most important part of your setup for deep sky photography. They are what allow you to attach your camera or telescope to a tripod. For serious deep sky photgraphy we need to track the stars and this is why most astrophotographers use either an ALT AZ mount or a more complex Equatorial one.
Taking photos of deep sky objects with just a tripod is possible but limits you to a very short exposure of of seconds, whereas a sophisticated equatorial mount can push this to several minutes. On top of this, for really detailed photos it is possible to use a guidescope to extend the exposure time beyond two to three minutes to 10 or 20 minutes or more.
When I used my first mount, a Celestron az alt mount, I was able to take photos of up to 30 seconds each before I saw star trails. With my ioptron CEM26 equatorial mount I can easily take exposures of 3 or four minutes, even though I may have to reject about 10% of these due to movement of the mount. This does, however, depend on the accuracy of polar alignment which is necessary with an equatorial mount.
How to Choose the Right Filters & Optics For Your Camera?
For shooting deep sky photography you may need to use various filters.
My sky is not bad but suffers from light pollution as do most skies. I live in a Bortle 5 area. This is enough to cause problems if shooting longer exposures as the sky will be overexposed and this will hide the details of the deep sky object you are shooting. A light pollution filter will usually help to make the sky darker and easier to process after you have stacked your images.
I have tried a few different light pollution filters including an SVBONY CLS and an Optolong L Pro Max. They are both good and I particularly like the clipin versions for my DSLR camera.
For deep sky objects with a lot of red colour in the nebula I have used an Astronomik 12nm HA filter to shoot the image in just hydrogen alpha. This is a good idea because this can be done even when the Moon is bright, as this filter doesn’t allow so much of the regular light including the glow of light pollution or moonlight to pass through to the sensor of the camera. Great photos, such as the above one I took of the Horsehead Nebula can be created by combining HA with the RGB colour data and the results are far more detailed than just colour only.
Start Taking Amazing Photos of Space Today!
I am still developing the techniques I use and gaining experience with deep sky photography and it seems to me the images I can achieve are getting better each time I try. Taking photos of space is a pleasure that comes from time and practice and a slow understanding of both the object you are photographing and the equipment you are using. Keep at it and you’ll soon be taking amazing quality images of Space!