Astrophotography is a rich and rewarding hobby, but the barrier to entry can be intimidating for beginners. The dizzying array of choices is a boon to intermediate, advanced, and professional astrophotographers. Beginners in the field, though, may find this variety terrifying. To get a handle on what someone needs to set up an at-home astrophotography platform, we spoke with Chris Guidry, a software engineer who is also an aspiring amateur astrophotographer.
Let’s narrow all of these myriad options down to a few concrete choices that will get you up and running with an astronomical imaging platform ready for growth.
Astrophotography in the modern era is effectively a robotics hobby. Your aim is to build a self-contained platform that can automatically find an astronomical object, track it within a few pixels for up to a dozen hours, and take as many subexposures of it as you can over the course of a night. Doesn’t it sound nice to let a robot do this for you while you snooze peacefully in a warm, cozy bed?
The brains of this operation is going to be a computer of some sort, whether it’s your laptop or a dedicated computer. I strongly recommend a dedicated StellarMate, a small, dedicated computer that you will attach to your telescope platform and operate remotely from the comfort of your couch. Choosing to run StellarMate is also a choice to use the wonderful open-source pieces of software KStars, Ekos, and INDI. These will be the heart of your imaging workflow.
An Equatorial Mount
The single most important device in your astrophotography platform is the equatorial mount. The mount is the motorized device, usually including a tripod, that is able to track objects in the night sky by compensating for the rotation of the Earth.
In a very direct way, your equatorial mount is a heavy metal clock that turns at exactly the rate of the Earth’s rotation. This is referred to as right ascension (RA), which runs from east to west. The mount can also point to any location north or south, known as the declination (DEC). Each time you move or set up your mount, you will polar align the mount, which means calibrating it to the location you are at by making sure that it is aligned to either the north or south celestial poles.
I use the Sky Watcher EQ6-R equatorial mount, and this mount is likely to last me for the rest of my astrophotography career.
An Imaging Scope
Choosing an imaging scope may be the decision that most beginners agonize about the most, but I can assure you that your scope is not the most important piece of equipment of your platform! The reliability and precision of your mount far outstrips the importance of your optics.
When I was just starting out, I assumed that I should use the most powerful scope in terms of magnification, but I quickly realized that many of the best objects to shoot are large deep space objects that cover larger areas of the sky. I was quite frustrated to start with a powerful 2,000mm f/10 telescope and then realize that I couldn’t fit the entire Andromeda galaxy or Orion Nebula within its field of view (i.e. it was too zoomed in).
After some deliberation and research, I arrived at the Williams Optics Zenithstar 73 which is much smaller than you might expect. In astrophotography, it can be helpful to think of your imaging scope as a huge camera lens rather than as a tiny Hubble. You will find many beautiful DSOs are available to you with a scope that’s f/6 or lower (i.e. less zoomed in).
An Astrophotography Camera
Whether you want to use your platform to do computer-aided astronomy (by capturing images onto a computer for easier viewing in the field) or artistic astrophotography (by capturing extremely long exposures of astronomical objects), your camera is going to be a critical component. Here you have the option to use a DSLR camera that you may already own, or a dedicated astrophotography camera. I prefer the dedicated cameras, as they are generally designed for autonomous operation and computer control without any additional setup.
I use the ZWO ASI 183, and for a beginner, I recommend the color version of this camera. I personally use the monochrome ZWO ASI 183MM Pro with a ZWO EFW filter wheel to images in each color separately. If you are up for the challenge of using a filter wheel, you’ll have a lot more flexibility over the long term.
First Upgrade: A Guide Camera and Scope
With a special-purpose astrophotography computer, a heavy-duty equatorial mount, a fast optical scope, and a dedicated astrophotography camera, you can shoot some incredible images – images that your friends and family will think you just stole from the internet. Shooting star fields, galaxies, and large nebulae will all be within your reach.
As you press further into the hobby, you’ll find that you want to start taking images for longer than about one to two minutes. There are beautiful nebulae that will only come to life with three-to-ten-minute exposures over many hours of imaging. When you attempt to shoot these long exposures, you’ll start to notice that if either your mount or polar alignment is off by even the smallest amount, the images you capture will smear out into an unusable mess.
Thankfully, there’s a brilliant and inexpensive “hack” that can open up exposures over many minutes: autoguiding! Autoguiding is a robotics method of controlling your mount by using a separate camera and small telescope to track a guide star and send small adjustments to your mount to keep that star in exactly the same view all night.
Your guide camera doesn’t need to have amazing resolution or noise characteristics, because all of the modern guiding software (included with Stellarmate via Ekos) can cope quite well with noisy images of your guide start. The key thing you’re looking for is fast imaging. For this, I use the William Optics 50mm Guide Scope with a QHY5l-II-C camera.
This camera is designed for planetary imaging of the planets within our Solar System, which is typically done by taking videos of the planets rather than individual images. This means the camera is sensitive and fast, which makes it an excellent autoguiding camera.
Second Upgrade: An Automated Focuser
Remember how I said you could shoot a full night’s worth of images, all from the comfort of your bed? Well, there’s just one problem, and that’s temperature. Over the course of the night, the air temperature of your site will inevitably drop as the Sun’s energy radiates away from the Earth.
Changing temperatures mean that the amazing focus you dialed in at 9pm is going to be just off by midnight and terribly off by 4am. You may find yourself setting an alarm every few hours to go out and turn the focus knob ever so slightly to maintain that critical focus in your images.
This hobby is a robotics hobby, so our very clever predecessors have figured this all out: all you need is a robotic focuser. I have my eye on the Pegasus Astro FocusCube 2 as the next upgrade for my platform. It’s a luxury, but I also value my sleep!