What is Coma, and Do I Need To Worry About It?
Coma is an optical aberration which affects all Newtonian (including Dobsonians) telescopes. Coma makes stars towards the edge of the eyepiece or image appear elongated, and is especially apparent in fast focal ratio Newtonians, such as f/4. This issue is easily fixable with a coma corrector, but this extra accessory is an added cost on top of the telescope itself and can get expensive. Generally speaking, you won't need a coma corrector if you're just observing visually unless you're using a fast Newtonian or prefer excellent edge views in your eyepiece. For deep sky imaging, though, a coma corrector is usually advised, especially if you're using a large sensor camera.
How Do I Collimate My Newtonian or Dobsonian?
Great question! Collimation is a simple process, and we're currently working on a video to best explain how to collimate your Newtonian or Dobsonian at home. You will need a collimation tool, and we recommend a laser collimator in most cases. Stay tuned!
Are Reflector Telescopes Good For Astrophotography?
That depends on the type of reflector. Many reflectors, including Newtonians and Ritchey-Chretiéns, make for great astrophotography telescopes! However, we don't necessarily recommend them for a beginner for a few reasons. For one, both Newtonians and RCs will need to be collimated from time to time. Second, both designs can be relatively large and heavy, which translates to needing a large and sturdy mount to support them. Lastly, RCs have a specific use case of long focal length deep sky imaging. All of that being said, both can be a great choice if you're an experienced imager and are not afraid of the challenges of more hands-on imaging. Dobsonians are capable of producing great astrophotographs, especially if you're just using a smartphone. However, Dobsonians are not a good choice for deep sky imaging due to their alt-az mounts, which can't account for field rotation.
If you're looking for a great beginner astrophotography telescope, a small refractor on a tracking mount is the ideal scope to enter the hobby of deep sky astrophotography. If you're hoping to do planetary imaging, Schmidt-Cassegrains are generally the preferred choice.