So far I have gone over both my personal history with astrophotography as well as the equipment I currently us. As I have mentioned before, I am no where near an expert in the fields of Astronomy or astrophotography, I just have a love for both and have, what I believe, some practical advice in getting started. Note: This is not an “end all of end all” type of guide. This provides my personal philosophy on the best way to get started in astrophotography as well as a starting place to being experimenting what is best for you.
Series Posts:
Part 1 – A Personal Overview
Part 2 – My Equipment
In the Beginning…
What I recommend is to begin simple and basic. Have a digital camera, preferably a – DSLR – and a tripod. Next, have some sort of star chart – This one by Celestron is really good, or you can go with a simple one like this one from Orion, or simply download an app on your smart phone, plenty of free ones! I would also recommend getting a book, or even doing research online on basic astronomy. Knowing terms like Right Ascension and Declnation will make your journey a lot easier.
Take your camera out on a dark and clear night, use your star chart and find a constellation. Point your camera up to the sky in the direction of the constellation you want a picture of and… well, let’s setup the shot:
1: Manual Focus – on Infinity
2: ISO 200
3: Aperture: f4.0 (or so)
4: Exposure: 10 seconds
5: Timer: 10 seconds (unless you have remote)
… Press the button to take a picture. Most likely you will need to make a few adjustments. check your focus by zooming in, you may need to slightly adjust it around infinity. You may need to set the ISO anywhere from 200 – 1600 (any higher will create a lot of noise), you can mess with your aperture, especially depending on what type of lens you are using. Depending on your lens, you may be able to raise your exposure – wide angle lenses can go for longer with no type of tracking. The one thing we know will stay constant is your timer or lack thereof. One thing is for sure, your picture will appear dark, but never fear, if your focus and exposure are good, processing the image after you take it off the memory card will help with the appearance.
Now, you may be wondering, where is the telescope? Good question, and the answer is simple, at this point in the journey, for it is a journey, there isn’t one. First things are first, you need to learn your camera and how it operates at night and you need to learn the night sky, at least to some degree, or at the very least, how to use a star chart to find what you are looking for. You can also take this opportunity to learn how to process, and maybe even stack, images that you take with programs like PixInsight, DeepSkyStacker, etc. and then maybe using other software such as Adobe Photoshop or Paint Shop Pro by Corel. Note: The latter two programs are not designed specifically for astrophotography, while the first two, and several others, are. Some, like PixInsight are full fledged processing software, others like DeepSkyStacker are more for staking images to make one, higher quality picture. Starting out, Paint Shop Pro is adequate for post-processing, but as you progress, you are going to want to take your processing as far as you can.
*Sidebar: With long exposure astrophotography there are a lot of nuances and steps to help make the process easier as well as more fulfilling. As mentioned in the previous post, I recommend getting “Digital SLR Astrophotography” by Michael Covington. Dr. Covington is far more knowledgeable then myself and has decades of experience in astrophotography. Also, find a local astronomy club and join, they may be able to help as well, and probably a lot more hands on!
I feel like an astronomer…
You can find Orion’s Belt, Lyra and the Pleiades now without assistance from your star chart. You have impressed your friends with being able to name some of the craters on the moon and you are ready for the next step. In my opinion, you are ready for a telescope! You may already have one, but I am going to assume you do not.
There are three main types of telescopes: Reflectors, Refractors and Catadioptric, which is a combination, or compound of the first two. There are also essentially two types of mounts for telescopes: Equatorial and Altazimuth. All three types of telescopes and the two types of mounts have advantages and disadvantages. For example, telescopes mounted on an equatorial mount have the ability to track stars very fluidly right out of the box. The down side, which isn’t huge, is that they can be both complicated to initially set up and they need to be aligned to true North. Altazimuth mounts are really easy to set up and use, but tracking isn’t possible without making extra pieces separately to enable you to do so. Sky & Telescope has a good article covering all three types of scopes while High Point Scientific has a good article focusing solely on Catadioptric scopes.
What I recommend getting is a small scope with an equatorial mount that has some sort of GoTo tracking. You will want the scope/mount to be able to piggy-back your DSLR camera (for long exposure shots outside of the telescope). Obviously, your budget will come in to play here. Even a simple tracking telescope on an equatorial mount can cost $1,000.00-2,000.00. There are several cheaper options – an example is one by Celestron, the AstroMaster 130 EQ – which is not a bad scope for beginners on a budget (I personally own the 114mm version of this). It does have a motor for tracking, however it is not computerized which makes things a lot easier. Regardless, I do recommend getting a scope with a mount that can track. A) to learn how to align and track with a telescope is going to be key for really good images of deep sky objects, and even planets. B) having the ability to track from the get go is a huge advantage moving forward in your astrophotography journey. If you do not care about tracking (for the moment, because you will!) you can go the far less advantageous route that I did and purchase a Dobsonian mounted reflector, such as the Orion 6″ Classic. Though you will not be able to track, its ease of use and its ability to facilitate lunar, solar (with the proper filter) and even some planetary photography is very nice for a beginner. Its large aperture and decent focal length will continue to serve you even after you upgrade to a scope that tracks.
*Sidebar: Personally, I am still working on the tracking thing! I do know how to setup, align and use a telescope on an equatorial mount but for budget reasons I have yet to buy one that does what I want, how i want for what I can afford. So, if you do decide to go the Dobsonian route, do not despair!
So, now you have a telescope… lets start taking… Learn how to use your scope! Your scope should have a finder scope, a focuser, and include a couple of eyepieces. Learn how to find object with the finders scope, focus with your eyepieces and follow along in the night sky. While doing this, research a couple of things that you will need for photography with your scope. If you ended up buying a scope with a motorized/computerized equatorial mount, make sure to pop your camera on the piggy-back moutn and try some longer exposures then you were able to do while on your nortmal tripod. This is also the time to take several 10-30 second exposures while tracking back to back (to back to back.. as in like 50) and try your hand at image stacking. While you are learning how to explore the night sky with your telescope, as well as it’s functions and capabilities, look for and order the following:
1. Adapter ring for your DSLR – attaches where your lens does
This will enable your camera to fit to many types of adapters:
2. Telescope / Eyepiece Adapters
- Prime Focus Adapter (this also includes an extension tube for eyepiece projection)
Note: Your telescope and camera combination may not be able to focus at prime focus because the focuser will not seat far enough in based on the focal length of the tube. There is some math here, but worse case you include in your purchase a 2x Barlow which you can then screw in the lens on the barlow to lengthen your focus - Eyepiece Projection (one above is a very simple version)
- “Digi-T” Rings
These attach to your eyepiece allowing them to be screwed into the adapter ring for your camera, or if you get the lens filter adapter (which is the next one), directly to your lens for afocal photography - Lens Filter Adapter – aka “Digi-Kits”
These enable you to attach an eyepiece directly to your lens or point and shoot camera at the filter ring
3. Eyepieces (for telescope)
- Plossl eyepieces that will fit in your telescope:
- 40mm
- 32mm* (second if choosing two)
- 25mm* (first if choosing one)
- 15mm
- 10mm
- These will enable you to get a wide range of views and magnification to play around with both while observing and while doing photography
- Note: Depending on what type of scope you have as well as the adapters you end up getting, some eyepieces simply will not work due to focal length or because the field of view is too small to do something like afocal photography.
Now you have placed your order, you are learning your scope, so when the shipments come in you will at least have a decent understanding of how your telescope works as well as your camera works for long exposure.
The Full Package…
You have a camera, a telescope and the adapters needed to couple your camera to said telescope, now what? First, you can do the math to determine if your scope can do Prime Focus. I can save you the trouble if you ended up buying the 6″ Classic Dobsonian from Orion, it wont. Bummer right? Not so fast! Attach your prime focus adapter to your camera, then unscrew your lens off your barlow lens, and in turn (a pun!) screw the barlow lens into the bottom of your prime focus adapter. Boom, you can do “prime” focus, or at least a modified version of it. Now set your sights on the moon and… you know what comes next!
1. Focus – Manual, must do it by hand at the telescopes focuser
2: ISO 200 – 400
3: Aperture: Telescopes f/stop – if 6″ Classic Dob, f8.0 (irrelevant to the process)
4: Exposure: 1/500 (to start)
5: Timer: 10 seconds (unless you have remote)
Now press that button, wait ten seconds and now you have a picture of the moon. Congratulations, you have now taken a picture through your telescope! Zoom in to see how your focus was. Not “perfect” (it never will be)? Use small adjustments (Note: many newer DSLR cameras have a live view, use it and zoom in to 10x and check that way. Will be clunky at first but it can help a ton). How dark is your photo? You can adjust both your ISO and exposure. Most of my moon pictures from quarter to full moon are at either 100 or 200 ISO and 1/125 exposure. Remember, you can play with the photo when your process it to change your contrast, histogram, etc.
You can do this same process by afocal photography, the main difference is instead of the prime focus adapter (an barlow if needed) you will connect your eyepiece to your camera lens. Remember you will need to take your eyepiece, remove the rubber eye guard and attach your little t-ting to the eyepiece. Once done, screw it into the camera filter ring adapter and put it in the scope. Now follow the same procedure as above, adjusting settings as needed. Couple of notes: Set your lens to Infinity focus just like you would with long exposure. It is possible to connect the eyepiece without the lens, just like you would with the prime focus adapter (results may very). Just like with prime focus, you will focus at the eyepiece, not the camera lens.
Depending on the type of lens you are using, a 25mm or 32mm eyepiece will give you a full view of the moon or sun (with proper filter!) that almost fills the viewfinder. I do not recommend using a wide angle lens because you will most likely get a lot of vignetting. Also, if you have the right filter ring adapter for your point and shoot camera, you can do afocal astrophotography the same was as with a DSLR!
The one thing you may get, especially with doing afocal astrophotography with a DSLR, is vibration. Your camera may have ways of mitigating it – experiment and see how it goes. If it ends up being too much, you can remove the camera from the eyepiece, place it on a tripod and set the camera as close to the eyepiece as possible. You can also try the handheld method, but just don’t shake!
What’s Next?
Depending on what type of telescope you have and what kind of mount, the sky is literally the limit. Can you track? Point towards a nebula and take a lot of short 2-5 second exposures and stack. Can’t track? Keep on going with the moon, switching out eyepieces or use eyepiece projection to try and zoom in. Buy a solar filter for your telescope and get some shots of the sun (and maybe some sunspots!). Note: Never look at the sun through anything that is not properly filtered (includes your own eyes!). Keep messing around with your settings, find out how your camera interacts with your telescope and the night sky, and send me a link to your Instagram, or wherever you decide to post your pics!
This little guide is not all encompassing. It is based on my own experience, which limited, has given me a lot of pleasure in taking pictures of the night sky. There is always room to improve and progress, and remember, there is no perfect astronomy pictures, but what is important is that they are perfect to those who take them.
The TL;dr
1. Learn your camera / tripod
2. Learn the night sky and how to navigate it
3. Buy a telescope that fits you
4. Learn your telescope
5. Get the adapters you need for photography
6. Attach your camera and experiment with your settings
7. Keep taking pictures and keep growing
SNC Astro - Photo 