Astrophotography on a Budget

 

Most astrophotographers have at one point or another been in an abusive relationship with their bank account (see also: people who build model trains). Any hobby combined with enough dedication and/or talent can eventually stress your finances, but various kinds of photography can have a higher starting cost due to the equipment required to take basic photos. Aside from cameras and lenses along with the software to process these photos, night sky photography in particular adds on precision tracking mounts, active guidance, specialized filters, and honestly more adapters than I ever imagined I would need. However, there are some ways to keep costs low, including thrifty purchases as well as making the best of your current equipment. With that in mind, here are some methods I used to save money over the years while slowly raising the quality of my equipment, and how to best cope with limited or cheap equipment.

Keeping Costs Low

Buy Used and Sell as you Go

Much like a row of hermit crabs all lining up to trade shells, you may be able to find equipment that was first purchased by someone else. My first foray into deep sky imaging featured both a used mount (CG5-GT) and camera (Canon 450D) which both served me well for over 2 years before moving onto other upgrades, but even some of those upgrades, specifically a doublet refractor and a T3i, were also bought secondhand.

Some of this equipment was new, including an 8” SCT and the Autoguiding scope and camera, but the rest was bought used. Some judgement is needed here. I was only willing to purchase this equipment because I trust the person who sold it to me and I was able to actually see it in person before purchase. I would have been much more hesitant to do so online, especially considering the hassle of trying to return 50lbs of equipment through the mail if it happened to be defective. Ironically, the only equipment I have ever had to return for a replacement turned out to be a brand new tracking mount which was more than 4 times the cost of my used CG5.

The other side of that analogy with the hermit crabs is that the now-old equipment can likely be sold. Absent any damage, telescopes don’t tend to significantly depreciate in value over time (and may actually increase if they are a popular model which has been discontinued, such as the Astrotech AT65EDQ), and if you take care of the rest of your equipment you could recover some of your initial costs as you work your way up to better equipment. Cloudynights Classifieds is a great website for this, but some good deals have appeared on Ebay and Amazon as well.

Don’t Buy Everything At Once

This isn’t something most people on a budget would even consider since they wouldn’t be able to do so in the first place, but its still worth mentioning for those about to purchase their first set of equipment. Aside from being somewhat expensive, Astrophotography has a steep learning curve. Each piece of equipment serves a purpose and may require maintenance and calibration or may perform unpredictably when paired with other equipment in certain conditions. Software may be required to control one or more of these components, and when this is all combined together it can create an incredibly complex and unique system which may overwhelm a prospective astrophotographer. Even regular astronomy can suffer from this. Buying a large and expensive new telescope without the drive to learn to use it can result in nothing but frustration and a strong urge to commit some kind of violence.

My first foray into night sky imaging started not with widefield Milky Way photos, but with a high-speed camera to use on planets with my 8” SCT. This also occurred in deep winter, meaning my first few frustration-filled nights were spent outside in the bitter cold willing my camera to capture a usable image while my numb fingers helplessly poked at random settings. The slightly-less-cold days following these nighttime sessions were filled with extensive research to patch the mistakes I was making and improve my next attempt. I may have thrown my camping chair more than once. The point is, even though I knew how to use my telescope, adding in a single $200 camera required days of use before I could even take my first useful image of Jupiter. Had I immediately spent the thousands required for a capable Deep Sky imaging rig, I have little doubt that the experience would have been even worse.

Specialize Your Equipment

Not all telescopes are equal. They have varying focal lengths, weight, aperture, and other factors which may limit what they can best shoot. If all you ever want to shoot is widefield images of the Milky Way, a 2000mm focal length SCT is unlikely to be a useful tool for your efforts. If high-resolution planetary images are your aim, a small refractor of 400mm focal length will similarly fall short of your goals. If you are just starting out, choosing one type of target will reduce equipment costs. Desiring the capability to shoot widefields, deep sky long exposures, and planets all at the same time is tempting, but each of these require different equipment and significant overall total cost.

If you’re not sure what you want to shoot but generally enjoy space or long exposure photography of the night sky, starting with wider focal lengths will be more forgiving and likely cheaper. Canon has some relatively low-cost lenses, such as the 50mm f/1.8, which are capable of capturing larger objects in our sky. Even your standard kit lens may be able to capture good images, though you may need to tape down the focus so it can’t move. The tracking requirements of widefield lenses are much more forgiving and a small tracker (such as the Sky Guider Pro) can be purchased for much less cost than a heavy-duty platform used for larger telescopes (and don’t forget, a telescope may be another several hundred dollars). Under halfway-dark skies you can also get away with taking static tripod shots so long as you are willing to accept some slight star trailing. Considering I did the opposite of this and started at 2000mm in focal length for my introduction to deep sky imaging, this is a definite case of “do as I say, not as I do.” You can be assured that when I recommend starting with wider focal lengths it is because I experienced the frustration of doing the opposite.

 
The Milky Way taken with equipment totaling less than $250. Canon T3i, 18-55mm kit lens, static tripod, taken in Nebraska in August 2017

The Milky Way taken with equipment totaling less than $250. Canon T3i, 18-55mm kit lens, static tripod, taken in Nebraska in August 2017

 

Using Budget Equipment

Manage Expectations….

Your first images won’t be great. They will probably be a combination of poorly focused, noisy, full of trailed stars, and the exposure time may not even be long enough to visibly capture your night sky object of choice. Your experiences may be worse if you chase targets beyond the reach of your equipment. Some objects simply are not bright enough to show up in photos if the focal length is too wide, the light pollution too strong, and the exposure time too short.

 
My first Deep Sky Image with a DSLR; M81 & M82 at 1400mm using several 20-30” exposures from a Canon 450D. The result is noisy, focus is bad, and the galaxy pair barely appears as a smudge. But its still there

My first Deep Sky Image with a DSLR; M81 & M82 at 1400mm using several 20-30” exposures from a Canon 450D. The result is noisy, focus is bad, and the galaxy pair barely appears as a smudge. But its still there

 

As I delved into Deep Sky Imaging, I mostly stuck to the brighter nebula because those could give me the best results from which I could learn and improve. Had I focused on dimmer and smaller objects which would barely produce an empty field of stars, I might not have learned as much about how to process my photos or improve my capture process. This is one of the reasons that the Moon, The Orion Nebula, and widefields of the Milky Way’s core are so popular among astrophotographers (both experienced and new); they are all relatively bright, easy to find, and generally easier to capture than nearly everything else in our sky (the Sun notwithstanding given the special equipment required).

For widefield setups, especially those limited to static tripod imaging, star trails are an excellent way of coping with equipment limitations. While astrophotographers usually try to avoid non-round stars by any means necessary, star trails will take this and use it as a strength, forming an image which shows movement of the night sky. Processing these images is also much simpler than tracked shots since the ground won’t blur and you don’t need to worry about star alignment, making them a good first choice for those learning to edit their photos.

 
Star Trails taken with a T3i + Rokinon 14mm lens in early 2019

Star Trails taken with a T3i + Rokinon 14mm lens in early 2019

 

…But Experiment as Well

You learn more from failure than success, and if you stick with Astrophotography there will be plenty of both to go around. You also will not know the limitations of your equipment until you approach them, and your definition of what is out of reach may change when you improve your skills in equipment capture and post-processing.

Remember also that a single sub-frame can look entirely different than a combined total, so even if a single image looks disappointing, consider persevering at least an hour or two to see how a stacked image will appear. One of the best images of the Andromeda Galaxy I’ve ever seen came from a stack of hundreds of minute-long shots, so even a limited individual exposure time can result in a good image if the total integration time is sufficient (among other factors).

 
M81 / M82 again, but taken a month after my first attempt using 50 x 50”

M81 / M82 again, but taken a month after my first attempt using 50 x 50”

 

A Special Note on Alt/Az Mounts

If you didn’t already know, Deep Sky objects are best shot using Equatorial mounts. The night skies have a central point of rotation close to the North Star (or the Southern Cross for those below the equator) and Equatorial mounts tilt to meet this axis. Alt/Az mounts, more often seen in visual observing-oriented setups, cause long-exposure images to suffer from field rotation even with precise tracking, meaning the outer edges of the image will show greater smearing than the center since they are tracking on two different axis. This does not mean such systems are unusable for Deep Sky, however, only that you may need to lean more on my advice of managing your expectations. The image of the M81/M82 galaxy pair seen above were taken using an Alt/Az system, specifically the Celestron Nexstar 8SE. While not ideal to use, taking the time to precisely level the tripod and ensure the stars for each alignment are centered will allow some useful imaging to take place. Since field rotation is less noticeable on circumpolar objects like the galaxy pair seen above, I chose those as my first targets. My record for using this equipment is 50” exposures near the poles and about 15” for Equatorial objects, which is enough for brighter nebula and should be sufficient for some star clusters.

If your goal is planetary, lunar, or solar imaging, this advice does not as much apply. The exposures needed for solar system objects (except comets) is almost always sub-second, making the requirements of long-term tracking much looser. With patience and persistence, even a hand-driven telescope like a Dobsonian can produce decent images of these objects as long as you are able to track with the telescope and manage your camera at the same time.

Acceptable Losses

Not every telescope is going to include perfect optics. Some telescopes were simply not made for astrophotography. My C8 would elongate stars near the edge of the field, for example. This was not something that could be fixed by my setup or calibration, it was simply an inherent issue in the optics themselves. Until I moved to a new telescope, I simply had to work around this, usually by cropping my images in by about 25%

 
Elongated corner stars in a C8-produced image of M81

Elongated corner stars in a C8-produced image of M81

 

Take Notes on your Failures

Nothing brings clarity on a needed upgrade like frustration in the field. Observing consistent issues with your current setup or images can indicate you may be making a mistake, but they may also indicate a need for higher-quality equipment or equipment which reduces or removes this issue. If all your stars stretch in a similar direction, this can indicate your alignment was poor or your mount has a tracking issue. This is something which can be fixed, either by taking more time in setup and polar alignment or other means, including recording periodic error (if your tracking platform has that feature) or even adjusting the drive rate of the mount itself. Conversely, if your stars all have odd color fringing on their edges, then your optics are likely suffering from chromatic aberration. This is an issue of hardware which likely cannot be solved and cannot be fixed without simply using a different telescope.

Planning for the Future

Improve your Processing

One of the best parts about digital photography is that photos can be reprocessed anytime you want. Saving your original photos and their calibration files (if you took any) will enable you to return to them at your leisure. The saying I have heard is “clear nights are for shooting, cloudy nights are for processing.” If you are in a part of the world lacking typically clear skies, the cloudy nights nights may be your best opportunity to improve the post-processing side of your shots.

Recording the settings used for various steps in your processing will help future projects as well. This is one of the reasons I enjoy using PixInsight - each process setting can be saved, so combing over old projects to see which settings were used and in what order is easy. Assuming you don’t frequently upgrade cameras, you may find that your application of noise reduction will be fairly similar across all photos, at least allowing some tweaks for varying temperatures and integration time. This is turn can make future processing more efficient for future projects since the settings are already close to optimal for many processes.

The Dumbbell Nebula / M27 processed only in Lightroom (left), then reprocessed later in StarTools (right)

The Dumbbell Nebula / M27 processed only in Lightroom (left), then reprocessed later in StarTools (right)

Free Software

On the note of saving money, Astrophotographers can often be lucky on the software side. Many of the software tools we use are freeware, especially those made for planetary imaging.

Planetary Imaging Pre-processor (PIPP): An image stabilizing software which can detect planets or landscape features and crop around them. This can make the stacking process less CPU-intensive when you’re using thousands of subframes. Also useful for stabilizing time-lapses

Autostakkert!2 (or 3): An image stacking software capable of churning through massive amounts of images

Registax: Capable of stacking, but also post-processing corrections like sharpening and color correction

WinJupos: Specialized software for de-rotating multiple images of planets into a sharper final result. May or may not be witchcraft

Deep Sky Stacker: For calibration and stacking of deep sky images, including a comet mode for tracking moving objects

On the Deep Sky Imaging side, processing options become more pricey. Adobe products like Lightroom and Photoshop both have subscription costs now, and even if my skies were perpetually clear I think I would have trouble justifying a subscription on editing software. Fortunately, Adobe still has Photoshop CS2 available for free! For Linux users, GIMP is another free alternative which has many of the same features as Photoshop (and is also available on Windows & MacOS). At the higher end of this is PixInsight which contains a treasure trove of software tools for calibrating, stacking, and processing all kinds of astrophotography (and it was created with this in mind).

Online Tutorials

Astrobackyard: The household name for amateur astrophotographers, this website includes equipment recommendations and reviews, processing tutorials, and more (and includes a youtube channel of the same name)

Forrest Tanaka: An inactive but helpful Youtube channel for those choosing equipment and stacking their first image

Doug German: Another inactive yet helpful channel with image processing tutorials

Light Vortex Tutorials: An advanced set of PixInsight tutorials for advanced users

Have an Upgrade Plan

This last point is probably deserving of more thought than most will give it, but it requires some long-term planning which doesn’t always end up being correct.

What I mean by an “upgrade plan” is to prioritize your purchases of better equipment to best serve the equipment you already use. Maybe you already have a decent camera and a good selection of lenses, but you only shoot on a static tripod. Would you be better served by purchasing another lens, perhaps a nice full frame camera, or a tracking mount? Unless you really enjoy shooting star trails or living under the tyranny of the 500 Rule (more like the 300 Rule anyway), my choice would be the tracking mount since that would unlock the ability to use longer exposure times; The best way I can describe choosing upgrades along this line of thinking is to choose whatever upgrade will both add to your capabilities as well as enrich the capabilities of the equipment you already have.

In late 2016 my setup included an SCT with a large 80mm guidescope all on top of a CG5-GT (now called the Celestron AVX), and my primary camera was a Canon XSi / 450D. This setup worked but involved significant setup and teardown time and the mount was not suited to handle that much weight for photography, leading to an appreciable amount of bad subframes (and by the sound of the gears, my neighbors probably thought I liked grinding coffee outside). I knew eventually I would need a better Telescope, Camera, and Mount, but how would I go about this? A new high-capacity tracking mount could not be first since I definitely could not afford one, and a new camera would not give me any advantage when my exposure time was so limited. The solution was to replace the telescope; a small refractor would be much lighter, reducing weight on the tracking platform, and the wider field would offer a much more forgiving focal length. A used Astrotech AT72ED doublet was only $400 and it fit both of these criteria, and the addition of a smaller $150 Orion 50mm guidescope meant that I was able to take 10 minute-long exposures with a very low amount of bad frames.

Since I was now able to make use of longer exposures, upgrading the camera now made sense, so my next upgrade (which happened months later) was a used T3i with an IR-modification (for better red light sensitivity). The last step was to purchase a new mount, not only for better tracking performance, but also because the higher payload capacity would allow me to upgrade to larger telescopes in the future.

Every setup is different and will have different requirements for what is considered an efficient upgrade based on available finances and what you want to shoot in the first place. Take the time to think about what equipment would most benefit you and your imaging and you may save some money - or as it often goes with expensive hobbies like this, you’ll just spend it slower.

 
Looking back, I’m honestly surprised this worked at all

Looking back, I’m honestly surprised this worked at all