THERE ARE MANY DIFFERENT OPTIONS TO CHOOSE FROM!
You have an interest in Astronomy, and you want to purchase a telescope?
There are many options, with many different features, and many different price ranges.
- There are refractors (with lenses), reflectors (with mirrors), compound telescopes, and “smart” telescopes.
- Telescopes will sit on azimuth-altitude tripods, equatorial mounts, Dobsonian mounts, and fork mounts.
- Telescope focusers and eyepieces come in 1 1/4” and 2” diameters.
- Many different types of eyepieces are available.
- There are standard, “red dot”, and laser finders.
- Filters can be used to enhance your image.
TAKE YOUR TIME! DO SOME RESEARCH!
In the end, choose a telescope that will be used, not one that will sit in a closet or your basement. Here are several very important things to keep in mind.
- DO purchase a well built telescope with quality optics from a reputable dealer (NOT a rickety scope with poor optics from the local department store.)
- A reflector (with mirrors) is often a better choice for a beginner than a refractor (with lenses).
- A Dobsonian mount (a “Dob”) is often a better choice than a traditional tripod.
- A reflex (“red dot”) finder (such as a Telrad) is often a better choice than the more traditional auxiliary finder scope.
- A Moon filter is useful when observing the Moon.
- It is NOT all about magnification. It is about APERTURE.
- The wider the lens or mirror, the more light a telescope captures and the more you can see.
- The light gathering ability of a telescope depends on the area of the lens or mirror, not just the width or diameter. Area = (diameter / 2) * pi (3.14) = diameter * 1.57.
- Magnification depends on the telescope and the eyepieces you use. Magnification = focal length (telescope) / focal length (eyepiece).
- Too much magnification can actually make it harder to see things. You will end up finding the “sweet spot” between magnification and clarity.
- A “smart” telescope might be a good choice rather than a traditional telescope.
- Before you buy a telescope, come out to one of the FAS outreach programs, talk with some of our members, and see the various options for yourself.
USING YOUR TELESCOPE
Once you purchase your telescope, there are a few things you should do as you use your telescope.
- Read the instructions that came with the telescope – they are not always the easiest to follow – but this is a good starting point.
- It might be useful to familiarize yourself with the basics of astronomy & stargazing before doing too much with your telescope.
- When setting up your telescope, make sure the mount/tripod is on a solid surface and is as level as possible.
- During the day, point your telescope to an object in the distance and align the finder so that it and the telescope point toward the same thing.
- Use an astronomy app or star map (such as Stellarium Web) to find and identify objects in the night sky.
- For beginners, the Moon and planets (particularly Jupiter and Saturn) are the best targets.
- Go observing during a crescent or quarter Moon – not during a full Moon, which is too bright.
- When observing the night sky, use the finder to locate objects in the sky and point the telescope.
- Your telescope’s magnification is equal to the telescope’s focal length divided by the focal length of the eyepiece.
- Do not try and use the maximum magnification – the image will be dim and fuzzy. Find a “sweat spot” between magnification and clarity.
- If you have two or more eyepieces (e.g. 25 mm and 10 mm), use the one with the longest focal length (e.g., 25 mm) first. This gives you a wider field of view with less magnification, but makes it easier to locate an object.
- Once you’ve located an object, switch to the eyepiece with the shorter focal length (e.g., 10mm) for more magnification.
- A 2X or 3X Barlow lens will increase the magnification by 2 or 3 times.
- Insert the Barlow into the telescope and then insert the eyepiece into the Barlow.
Featured Resources
Smart Telescopes
The world of telescopes is changing. Recently, several companies have introduced “smart” telescopes for astrophotography.
These allow even novice astronomers to jump into the world of imaging. This might be an option for you.
The ZWO Seestar S50 & S30 along with the Dwarf Labs Dwarf 3, with prices of $600 or less, have been getting a lot of attention.
More Information
If this isn’t enough, we have much more information for a deeper dive into all of this.
On-Line Resources
- “How to Pick the Perfect Beginner Telescope.” Planetary Society. August 12, 2020.
- Adrian R. Ashford. “How to Choose a Telescope.” Sky & Telescope. January 25, 2021.
- Editors of Sky & Telescope. “How To Choose Your First Telescope.” Sky & Telescope. December 15, 2016.
- Tony Flanders. “What to Know before you Buy.” Sky & Telescope. 2010.
- “How to Choose a Telescope.” Orion Telescopes.
- Ken Wilson. “Are cheap telescopes worth it? The answer is no.” Astronomy. November 15, 2023.
- Elena Stone. “Telescope Specs Explained By An Expert.” Little Astronomy. September 9, 2023.
- “Telescopes.” FAS Astronomers Blog. November 2022.
- Luna Gregoria. “Telescope Specs Explained.” Astronomy Source. September 21, 2022.
- Brian Ventrudo. “The Five Numbers That Explain a Telescope.” Cosmic Pursuits. April 4, 2020.
- “How Do Telescopes Work.” NASA Space Place.
- “Beginners Guide to Using a Telescope.” High Point Scientific.
- Alan MacRobert. “Getting Started With Your New Telescope.” Sky & Telescope. December 25, 2023.
- “Magnification – Part I” Astronomical League Handouts.
- “Magnification – Part II” Astronomical League Handouts.
- “Magnification and the True & Apparent Field of View (FOV).” Astronomical League Handouts.
- “Ampliación y el campo de visión real y aparente (FOV).” Folletos de la Liga Astronómica.
Here is a flyer with some useful information:
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