Telescope Buying Guide
Telescopes make great gifts, but there are a lot of options out there. Use this guide to help understand your choices.
Check out these recommendations for buying a telescope from our Planetarium Director, Elliot Severn! Elliot does backyard astronomy and astrophotography and has a list of helpful suggestions for getting started.
If you are interested in astronomy and want to buy your first telescope, you might be overwhelmed by the variety of options available. There are several types of telescopes, each with their own advantages and disadvantages. Some features might seem appealing but are not particularly useful for beginners. In this guide, I will give you a brief overview of the main types of telescopes, the pros and cons for each, and why I recommend the Dobsonian as the best type of telescope for beginners.
The three main types of telescopes are refractors, reflectors, and catadioptrics. Refractors use lenses to bend light and form an image at the eyepiece. Reflectors use mirrors to reflect light and form an image at the eyepiece. Catadioptrics use a combination of lenses and mirrors to fold the light path and form an image at the eyepiece.
Refractors are the simplest and most familiar type of telescope. They have a long tube with a lens at the front and an eyepiece at the back. They produce sharp images and are good for observing the moon, planets, and double stars. However, they also have some drawbacks. They are expensive for their size, as high-quality lenses are hard to make. Lower end (achromatic) refractors also suffer from chromatic aberration, which means that different colors of light do not focus at the same point, resulting in a rainbow-like halo around bright objects. To minimize this effect, higher end apochromatic refractors use specialized glass and three or more lens elements to correct for chromatic aberration.
Reflectors are the most common type of telescope among amateur astronomers. They have a wide tube with a mirror at the bottom and an eyepiece at the side. They produce bright and detailed images and are good for observing deep-sky objects like nebulae, galaxies, and star clusters. They are also cheaper than refractors of the same aperture, as mirrors are easier to make than lenses. However, they also have some drawbacks. They require occasional maintenance, as the mirrors need to be aligned (collimated) and cleaned. They also suffer from coma, which means that stars near the edge of the field of view appear distorted or elongated. This can be resolved with an optional accessory called a coma corrector.
Catadioptrics, also known as cassegrains or SCTs, are the most versatile type of telescope. They have a short tube with a lens-mirror system that folds the light path and reduces the length of the optical tube. They produce sharp and bright images and are good for observing both planetary and deep-sky objects. They are also compact and portable, as they have shorter tubes than traditional reflectors. However, they also have some drawbacks. They are expensive for their size, as they use complex optical components. They also suffer from coma, which can be resolved by corrective optics in higher end models.
So, which type of telescope should you choose as a beginner? My recommendation is to go for a Dobsonian. A Dobsonian is a type of reflector that has a simple wooden mount that allows you to move the telescope up and down (altitude) and left and right (azimuth). A Dobsonian has several advantages over other types of telescopes:
It is easy to use! You do not need to worry about complicated settings or adjustments. You just point it at what you want to see and enjoy the view.
It is affordable! You can get a large aperture Dobsonian for a fraction of the cost of other types of telescopes with smaller apertures.
It is powerful! A large aperture Dobsonian can collect more light and resolve more detail than other types of telescopes with smaller apertures.
It is fun! A Dobsonian gives you a direct and immersive experience of exploring the night sky. You can scan the sky for interesting objects or follow a star map or guidebook.
One feature that you might be tempted to get as a beginner is a computer-controlled “go-to” mount. This is a mount that has motors and sensors that can automatically point the telescope at any object in its database. While this might sound convenient and cool, I would advise you to avoid them with your first telescope for several reasons:
It is expensive. A computer-controlled mount can add hundreds or thousands of dollars to the cost of your telescope.
It is complicated. A computer-controlled mount requires batteries or power supply, alignment procedure, software updates, troubleshooting, etc.
It is limiting. A computer-controlled mount can make you dependent on technology and prevent you from learning how to navigate the sky by yourself.
It is boring. A computer-controlled mount can take away the thrill and satisfaction of finding objects on your own.
In conclusion, if you are looking for your first telescope, I would recommend getting a Dobsonian reflector with a large aperture (at least 6 inches or 15 cm). This will give you the best performance and value for your money. You will be able to see a lot of amazing things in the sky and get a lifetime of enjoyment out of it.
If you aren’t ready to invest in a telescope just yet, check out more affordable options in our astronomy binocular buying guide.
Many beginners are eager to jump straight into taking photos through their telescope. The guide above covers visual astronomy, which I recommend that everyone master before progressing to astrophotography. While it is possible to take photos of the moon and planets through visual telescopes, deep sky astrophotography requires specialized equipment that quickly adds up to thousands of dollars.
However, it is possible to take beautiful photos of space without a telescope. If you have a DSLR or mirrorless camera, check out our widefield astrophotography guide for beginners.
My last piece of advice is try before you buy! Visit a local astronomical society where you can meet amateur astronomers, look through their equipment, and learn from their experience.