How to Setup Your Telescope for Astrophotography?
We’re all fascinated when we see images from the Hubble telescope. But the first question is always “how to do astrophotography?”.
We wonder if we could take a photograph of an object in space that could even come close to the images from Hubble.
The answer is that we can’t repeat what Hubble has captured, but we can take some amazing pictures of the moon, planets and some deep space objects that will both surprise and delight us.
It’s just a question of mastering the art of astrophotography.
Will my telescope work for astrophotography?
Yes it will, depending on what you want to photograph.
The moon is the easiest subject and just about any telescope will give you an excellent photo of the moon.
In fact, a Digital Single Lens Reflex (DSLR) camera with a telephoto can give you some great shots of the moon without a scope. Beyond the moon a lot depends on some critical factors you need to take into consideration.
The importance of a motor drive
Many photographs of objects in the night sky require time exposures that can last from a few seconds, to a few minutes and even hours.
Anytime you do a time-exposure through a telescope, you have to compensate for the rotation of the Earth with a motor drive on your telescope mount. Otherwise you will either get a smear of light across your exposure, or streaks called star trails.
The best way to understand this is to point a digital camera on a tripod at Polaris, the North Star. If you set your camera for a time exposure of 20 minutes you will see streaks of light describing a circle around Polaris. That’s because all stars in the sky seem to orbit Polaris due to the alignment of the Earth’s polar axis with the North Star.
As interesting as this picture may be, it points to a daunting problem that affects all astrophotography.
All objects in the sky move in an arc defined by the rotation of the Earth. As a result, it’s impossible to do an effective time-exposure without a carefully aligned motor drive on the mount.
Motor drives are designed to work on all types of mounts although an equatorial mount with a motor drive appears to be one of the best. However, there are scopes with drives on fork mounts and alt-azimuth mounts that work just as well.
What is the best telescope for astrophotography?
There are numerous opinions but many astrophotographers prefer the catadioptric telescope.
It has a short focal length, excellent light-gathering capability and its compact size tends to handle the added weight of a camera better when the motor drive is engaged. They also work well with smaller digital cameras specially designed for telescopes.
Other astrophotographers prefer a refractor because of its excellent optics, but many use a refractor with a shorter focal length to also compensate for the added weight of the camera or simply use the lighter digital telescope attachment.
Reflectors can be used for astrophotography but if it has a long length or focal length it’s better to attach a lightweight digital camera.
This gets to the three basic camera options you should consider.
Camera Option 1:
The complete kit. There are specialized digital cameras designed specifically for telescopes that are compact, lightweight and attach directly to the telescope eyepiece.
These are usually connected to a computer or an electronic device like a tablet or wireless phone to both display and capture the image.
They can be used with any type of telescope and offer the added benefit of being able to view the image on a larger screen. Here’s an example of that kind of setup:
This is the Schreiber Telescope 3.5″ Refractor Astrophotography Bundle – 90 mm Refractor with eyepiece camera on a German equatorial mount. All of the elements including the scope and tripod are included in the kit. You need to provide the display which in this instance is a tablet. A laptop computer could also be used for the display.
This is an easy setup and is sold as a package so you don’t need to configure adapters and cameras to begin shooting.
Camera Option 2:
Option two is a simple, inexpensive digital imaging camera designed specifically for telescopes.
This camera pictured is called the Orion StarShoot USB Eyepiece Camera II.
It’s a relatively inexpensive digital camera that attaches to the eyepiece of most any telescope and plugs into a USB port on your laptop computer or tablet.
It’s essentially the same concept as Option 1 but that’s a complete kit and this is about just the digital camera. It comes with a software package.
This option will also allow you to see the image on your laptop or tablet and you can either shoot still photos or video.
Its capability for long-exposures is once again determined by your motor drive, but the benefit of most digital imaging is that you can see and adjust exposures and manipulate them later with software to enhance brightness, contrast and color to some degree.
This is a good option for lunar and planetary astrophotography but with a motor drive and some experimentation could produce good results for some deep space objects.
This type of camera can also work with Dobsonian scopes which rarely support a motor drive capability and typically aren’t used for astrophotography.
There are other cameras of this type that offer various options and varying software.
The general guideline in terms of price and features is that the better your scope, the better your camera should be.
A low quality, digital camera will compromise the exceptional quality of a great scope.
Camera Option 3:
Many astrophotographers believe that a Digital Single Lens Reflex camera or DSLR is the best choice for imaging through a telescope.
You’ll need to configure adapters to a Digital SLR camera that connects to your scope for astrophotography.
This can be a complex task if there is no adapter for your particular camera or your scope manufacturer doesn’t make them.
Most adapter kits look something like this, although there are also optional support brackets to compensate for the weight of the camera.
The benefit of a DSLR that many astrophotographers highlight is the ability to make numerous adjustments with the camera related to film speed, exposure time and settings for dim light such as deep space objects.
Advanced DSLR cameras also have significantly more megapixels that can deliver better quality images than a standard digital camera attachment described in Options 1 and 2.
The biggest challenge with a DSLR camera attached to a scope is the weight of the camera and the camera mounting adapters. It’s why compact telescopes are preferred by many astrophotographers because the weight of the camera is closer to the center of gravity of the mount.
A reflector on a tripod with a long focal length and a long tube may get off balance if a heavy camera is attached to the eyepiece. You can compensate with counterweights if the balance is a problem.
Here’s an example of a camera with a DSLR. You’ll notice the short tube on this Catadioptric scope.
One thing to keep in mind if you are using a DSLR camera is a cable release.
Depressing the shutter by hand could be enough to cause vibration and compromise your exposure. If you don’t have a cable release capability, set the timer for a few second delay before the exposure begins. That should alleviate any vibration.
So how do I take the pictures?
We could write a book about how to take great pictures through your telescope, but for the sake of brevity in this article – here are some of the best astrophotography books for beginners that cover the subject fairly well.
Just click on the book cover and it will take you to Amazon.com where you can read more about it:
Where do I go from here?
Our recommendation is to start simply and inexpensively.
Once you’ve captured a few photos of the moon, Jupiter and Saturn you’ll either be satisfied or want to push further.
Keep experimenting and keep a log of your exposure times, setup, and other factors that gave you a good result. As time goes on you might decide to upgrade and try more advanced subjects in deep space such as the Pleiades and a nebula or two.
If you really want to push it further you can learn more and invest more and eventually master the art and craft of astrophotography.
You might want to take a look at this video for another real life example:
Image Credits: 1.