Jeffrey Baltus Astro

Astrophotography Equipment

Before getting into astrophotography equipment for imaging deep sky objects (which is my preference), a brief mention of lunar/planetary imaging. The techniques and equipment used for these two are vastly different. For lunar/planetary imaging, you want a high focal length and large aperture telescope with a camera that via “lucky imaging” can take a high frame rate video and has an appropriate pixel size to your optics and seeing conditions. For more information, follow this guide from Cloudy Nights that should have all the information you need.

Now, onto equipment to do deep sky object imaging…

Smartphone

Most adults have a smartphone, which you can actually use to take astrophotography photos. My Google Pixel 6, for example, has a built in “astrophotography mode” in the default camera app. iPhone users can use the AstroShader app while other Android users may be able to take some long exposures under a “Pro” camera setting (depending on your phone model) or you may have luck with some other apps that you find on Google Play Store that allow for long exposures.

Here are two example images I produced using this method from my fairly light polluted suburban Bortle 6 skies:

In the image on the left, just behind the trees one can faintly spot C/2023 A3 (Comet Tsuchinshan–ATLAS) – note: this is much more apparent in the time-lapse version (not shown here) and should not be confused with the satellite trail on the lower-right third of the image. The image on the right features a very small smudge in the lower left, which happens to be the Andromeda Galaxy. (Note that when I did this for both images, I simply placed a number of our kids’ blocks on our deck’s fireplace to hold my phone – the “tripod/stand” doesn’t have to be anything fancy, as long as the phone remains still.)

Smart Telescope

Smart telescopes (e.g., Seestar or Dwarf) are an incredible and amazing option for those not wanting or able to put in thousands of dollars over many years to get a full astrophotography set-up, but who want to capture long tracked exposures. These are incredibly small and lightweight, perfect for easily transporting them to dark sky locations (to achieve better images). Additionally, these have the added benefit of allowing individual frames to be saved and later manually processed to bring out even more detail than what the automatic stacking and processing can achieve. To me, however, the biggest downside to smart telescopes is the inability to upgrade; for example, if you purchase the Seestar S30 Pro, you are “stuck” with the 160mm focal length and 30mm aperture because everything is contained within the one device and individual components cannot be replaced. (This is in contrast to a custom dedicated astrophotography rig, where I can switch between using my RedCat 51 and CarbonStar 200 depending on which object I plan to image.)

Custom/Upgradable Dedicated Astrophotography Rig

When it comes to building a custom/upgradable dedicated astrophotography rig, there are many options to choose from depending on your budget. There is also a lot to learn about how each component makes your imaging both easier and obtain better results. Below, I walk through the order in which I would suggest you purchase your equipment if you are looking to build this slowly over time with a short discussion about what each one does to improve astrophotography images. (If you want to jump in with a large budget and purchase many of these right away, I include an example rig set-up at the end of each “step” that I would be very happy to use if I had to pick from scratch today. Note that when putting together these example rigs, I do not mention every adapters/connectors/cables needed, just the main components.)

1. DSLR/Mirrorless Camera

The first thing someone needs is a camera that is able to take RAW images. If you’re just looking to get started with astrophotography, you may already have a DSLR or mirrorless camera that you can use for this. If not, then you can do what I did when I started and purchase a used DSLR (I chose the Canon EOS Rebel T7i, a.k.a. Canon 800D). From there, you can begin taking photographs of constellations and even deep sky objects using nothing more than a tripod and perhaps an intervalometer. For a great introduction to doing this sort of untracked (i.e., camera on a simple tripod) astrophotography, check out this video from Nico Carver on his Nebula Photos YouTube channel. (I experimented with doing this even after having a mount and dedicated astrophotography camera, as it is actually quite fun.)

One very important note when picking a DSLR/mirrorless camera is to ensure that it does not have well documented artifacts using Mark Shelley’s website.

Example “rig” set-up (~$400-500):

  • Canon EOS Rebel T7i
  • Stock lens (or optional upgrade for deep sky objects: Samyang 135mm f/2.0 ED UMC Lens)
  • Simple sturdy tripod
  • Camera specific intervalometer (can be found for cheap on Amazon, for example)

2. Mount

After having a camera that can take RAW images, the next and most important purchase you will ever make for your rig is the mount. Instead of taking roughly 1 second exposures doing untracked images, a mount will move to counteract the rotation of the Earth and allow for up to 30-60 second individual exposures. Much more light/detail will be captured when exposing for longer periods of time, as well as a significantly higher Signal-to-Noise ratio as you’ll overcome the read noise of your camera and the sky glow from light pollution. If you plan to do this hobby long-term and aren’t just “testing it out”, I highly recommend getting as large of a mount (by payload capacity) as you can. Furthermore, a strainwave or harmonic drive mount is often lighter than a traditional equatorial mount and would be my recommendation.

I started out with a Sky-Watcher Star Adventurer GTi, which allowed me to learn a lot though with only 11 pounds of payload capacity I quickly outgrew it. If you go down an equatorial mount path, I would recommend something like that Sky-Watcher EQ-AL55i Pro instead due to its higher payload capacity. However, if you can afford to also get a control computer like an ASIAir at the same time then I would look into a MLAstro SAL-33. (I currently image with a ZWO AM5N, but I’ve heard so many great things about both the SAL-33 and especially the MLAstro founder Minh Nguyen that I likely would have gone down that route instead.)

Example rig set-up (~$1200):

  • Canon EOS Rebel T7i
  • Stock lens (or optional upgrade for deep sky objects: Samyang 135mm f/2.0 ED UMC Lens)
  • Sky-Watcher EQ-AL55i
  • Camera specific intervalometer (can be found for cheap on Amazon)

3. Guiding and Computer

Going beyond simple tracking is the introduction of guiding. Your main camera should now able to take 2-5 minute exposures without issue in this step thanks to a second (guide) camera that takes very short exposures (typically 1-2 seconds). If the stars have moved significantly from the previous short exposure on this guide camera, the computer software sends a “pulse” to the mount so it counteracts the periodic error and any tracking issues from the mount to ensure that the main camera remains fixed on the object(s)/stars of interest with no image trailing. To do this step, you’ll need a few pieces of gear including the guide camera, very likely a guide scope or Off-Axis-Guider, and a computer to run it.

There are a few ways to do guiding, and which one to pick will likely depend on your long-term astrophotography goals:

  • Guide Scope: you can keep the guide scope and camera completely separate from your imaging train. The advantages to this are that it is easy to incorporate into any set-up because you don’t need to worry about compatibility in connecting anything between your lens/telescope and imaging camera. However, long-term this can cause issues with flexure (e.g., wind moving this guide scope but not the main imaging optics) and guiding issues with a short focal length guide scope combined with very long focal length main imaging optics.
  • Off-Axis-Guider (OAG): this device “picks” off light from the main imaging train to send to the guide camera, and it connects between the lens/telescope and camera. This completely eliminates the need for (and the primary issues with using) a separate guide scope. If I were able to pick a brand new set-up to use for my imaging today, it would definitely include an OAG (rather than my current ASI2600MC Air which utilizes a duo camera). This is my recommendation, if you are able to make it work.
  • Duo Camera: if you are able to purchase a dedicated astrophotography camera, some also come with a guide camera sensor included and thus uses the main imaging train for guiding. For example, the ASI2600MC Air that I currently use includes the ASIAir, a main imaging camera, and a guide camera all in one.

For guiding, you will also need to use a computer to run everything. If you already have a laptop or mini-pc, then you can easily use free software like NINA and PHD2 to do everything you need. Another option that is relatively easy to use with a smartphone or tablet is the ASIAir (which I admittedly have enjoyed and it serves me well).

Example rig set-up (~$2500):

  • Canon EOS Rebel T7i
  • Samyang 135mm f/2.0 ED UMC Lens
  • MLAstro SAL-33
  • OAG
  • ZWO ASI220MM Mini Monochrome Astronomy Camera
  • Laptop (already owned) running NINA and PHD2 (alternatively, ASIAir)

4. Telescope

If you haven’t gotten a good lens at this point (like the Samyang 135mm), you will want to upgrade your telescope to have better optics. When beginning you should start likely with a widefield refractor, ensuring it provides a flat field throughout your camera’s sensor without any coma present; I’ve been very happy with my RedCat 51 for my widefield imaging, for example. When looking for a telescope, be sure to look for one that is apochromatic (shortened to APO, be sure it is not achromatic) or has extra-low dispersion (ED). These telescopes help eliminate chromatic aberrations and color fringing around bright objects (like stars).

Note that when you eventually want a greater focal length telescope, be sure to consider your image scale and seeing conditions.

Example rig set-up (~$3000):

  • Canon EOS Rebel T7i
  • Williams Optics RedCat 51 Gen 3
  • MLAstro SAL-33
  • OAG
  • ZWO ASI220MM Mini Monochrome Astronomy Camera
  • Laptop (already owned) running NINA and PHD2 (alternatively, ASIAir)

5. Dedicated Astrophotography Camera

The last upgrade to make or decide on is a dedicated astrophotography camera. For this, be sure to take into account the image scale of your set-up, along with field of view using this and this. Typically a camera with a cooled sensor will perform better than one without, but there are many factors at play that will help determine the Signal-to-Noise Ratio of your exposures.

Example rig set-up (~$4200):

  • ASI2600MC Pro
  • Williams Optics RedCat 51 Gen 3
  • MLAstro SAL-33
  • OAG
  • ZWO ASI220MM Mini Monochrome Astronomy Camera
  • Laptop (already owned) running NINA and PHD2 (alternatively, ASIAir)

6. Optional Accessories

There are a few additional accessories that while not necessary for taking images can absolutely make things easier and/or help improve your images.

  • Dew Shield: if your telescope did not already come with a dew shield, it may be helpful to get one to help block stray light and prevent dew from forming on your optical train. This will be very telescope specific, though some handy astrophotographers have used yoga mats successfully.
  • Camera Angle Adjuster (CAA): this allows an image to be taken and plate solved, then the CAA can rotate the camera as needed to ensure the rotation of the framing is as desired. This helps me significantly when doing multi-night projects with an imaging newtonian that I need to take apart after each night (so when I put it back together, the framing will almost never be exactly matching without this CAA).
  • Electronic Auto Focuser (EAF): this connects directly to your telescope and will adjust the focus with the help of computer software to ensure focus is perfect. It can run at the beginning and periodically throughout the imaging session to ensure perfect focus remains for all images.
  • Filters and Filter Wheel/Drawer: whether one lives in light polluted skies, desires to use monochrome camera, and/or wants to use narrowband images to achieve the “Hubble Palette” (i.e., SHO), filters and a filter wheel/drawer will be needed. I recommend beginners start with a One-Shot-Camera (OSC) for color imaging before using a monochrome imaging camera or using filters. However, even with a OSC camera, dual band filters can still be used. I strongly do not recommend using any sort of “light pollution filter”, as those do block some light but they are primarily aimed at blocking what used to be the primary wavelengths that street lights had (but not anymore).
  • Monochrome Imaging Camera: eventually, you may want to switch to monochrome imaging camera as you become more experienced for slightly higher quality images. As mentioned in filters, I highly suggest starting with a OSC camera.