A good telescope requires costly precision optical and mechanical parts. A first time telescope buyer is overwhelmed by the variety of telescopes, but usually has something in mind like one of the telescopes below:
Modern manufactures have become very adapt at imitating these classic telescope forms at low prices. The problem is that these telescopes do not perform nearly as well as similar looking telescopes from 50 years ago or more modern telescope designs. Sky & Telescope has their own take on Hobby Killers: What Telescopes Not to Buy. I'll focus here not only on what to buy, but what to look for in any scope.
You will quickly find many different kinds of telescopes with more choice as you spend more. Do you want to observe planets, deep sky objects, or both? Do you want to observe visually or try astrophotography? Will you need to travel with your scope? A first time buyer doesn't have much experience for choosing.
The good news is that you can find reasonably priced telescopes that will let you explore your interests in the price range of $50 to $400 new. These telescopes are far better than any that Galileo used!
Second hand expect to save 1/3 to 1/2 of new prices. An easy to use starter scope may be all you ever want. If you discover interests that require something more, a good starter scope will still be a good investment. You will have the experience to make a better choice in a larger more complex telescope and can use your starter scope for easy quick looks. I'm an astrophotographer and I often set up an additional telescope or two for myself and guests to observe visually while I'm imaging.
The two most important parts of any telescope are:
The mount is the most important part of any telescope. Both a mount head, to allow pointing the telescope and a tripod or pier, to hold it off the ground, are required. Typical beginner telescopes average focal length is about 1000 mm and may magnify the image from 50 to 200 times. This makes them very sensitive to wind and vibration. You can't enjoy a telescope when the image is jumping around and it's hard to find and focus on your target. Most of us picture a telescope mounted on a tripod or a pier with an astronomical mount like the ones above. The reality is that a tripod and mount rigid enough to hold even a small telescope steady costs hundreds of dollars. Telescopes sold with traditional mounts at reasonable prices bundle an inferior optical tube on a wobbly mount. A scope like this makes stargazing a chore rather than a pleasure.
An easy way to judge the stability of a telescope on a mount is called the tap test. Focus on a star or distant object during the daytime. Tap the front end of the telescope firmly (but not hard enough to push it away from your target). Your target will twitch and settle down after a while. If your telescope takes longer than two seconds to settle down, a more rigid mount is needed. A while back I swapped a tripod that settled in 2 seconds for one that only took about one second and found that the telescope was much easier to focus.
The aperture of any telescope is the diameter of the primary mirror or lens used to gather light. The brightness of targets seen through the telescope increases with the square of aperture. The detail (and useable magnification) of what you see increases linearly with aperture. Bigger is better but becomes expensive quickly. Larger telescopes are heavier and take more time to set up, as a result they often get used much less often.
Good optical quality gives you pinpoint stars without color aberrations to the edge of your field of view. Budget telescopes and eyepieces are less clear away from the center of view because eliminating these distortions requires more time and expense in shaping mirrors and lenses. Look for pinpoint stars without any color ghosts or rainbows over most of the field of view. Reasonably priced refractors will always show color ghosts around bright objects, reflectors should not. Getting a near perfect image across a wide field of view can be costly. Pointing a beginner telescope so that what you want to see is in the center of view is free! A reflector with a parabolic primary mirror will give sharper views across the full field of view than less expensive spherical mirrors. Refractors require a compound objective lens to avoid color halos on the objects you view. Look for a doublet refractor to remove some color aberrations. An apochromatic (APO) refractor will use a triplet objective or enhanced dispersion (ED) glass to provide color correction comparable to a reflection telescope. These refractors are usually too expensive to be considered starter telescopes.
I recommend a Dobsonian mount for a starter telescope. The Dobsonian mount is held off the ground or table by three short feet making it stable and rigid. No machined metal parts are needed so it is very easy and inexpensive to make. Alt-Az mounts like the Dobsonian are easy to use because the observer can move them freely in any direction. The single arm variation works well with small table top telescopes. Larger telescopes require support on both sides.
Dobsoinan mounts are not suitable for telescopes that don't have the eyepiece at the top of the tube. This is why they are always paired with Newtonian reflecting telescopes.
Reflectors give you more aperture and a brighter image for the price than other kinds of telescopes. Newtonian reflectors with the eyepiece at the side are easiest to use for visual observation. They need occasional alignment for best performance, but this is easy to do. Reflectors do not have the false color halos around bright objects that moderately priced refracting telescopes show.
Aperture: You can find good starter telescopes with from 75mm (3") to 200mm (8") of aperture. A 3" scope will show the moon and planets along with some of the brighter and larger nebula and galaxies well. An 8" scope will show you objects over 2 stellar magnitudes dimmer and the full moon will be too bright to look at for long without a filter!
Focal Length: A faster focal ratio, short focal length telescope (< 700 mm) will give you a wider brighter view. A long focal length (> 1200 mm) gives a narrower field of view, but makes bright objects like planets or the moon can be seen in more detail with a comfortable eyepiece.
For all but the lowest price telescopes the mirror expect a mirror with a parabolic profile. This will give a clearer view off axis than a less expensive spherical mirror.
Eyepieces are sized by their focal length. The ratio of telescope to eyepiece focal length sets the optical magnification. Additional characteristics like eye relief, exit pupil and apparent field of view can make an eyepiece more or less comfortable to use. Good eye relief is especially important if you will view with eyeglasses on and is hard to find in short focal length eyepieces. Make sure that your telescope will fit an eyepiece with a 1.25" barrel. A better eyepiece is the easiest and best upgrade for most starter telescopes. Modern quality eyepieces use a 1.25" barrel and not the 0.965" diameter found these days on toy telescopes.
Inexpensive eyepieces (e.g. Hyghens, Kellner, Ramsden) will have color aberrations, narrow fields of view, and less eye relief. Better eyepiece designs (Konig, Orthoscopic, Erfle, Plössl, ...) offer dramatic improvements in quality of view and comfort, but can easily cost many times what a starter telescope costs. Good eyepieces will be made with a metal barrel with optical glass lenses coated to reduce reflections. It's better to one good eyepiece that is a keeper with your telescope than several that will be headed for the trash bin once they are replaced.
The most common good quality eyepiece is the Plössl with good value at reasonable prices. They are offered by many makers and may be included with the more expensive starter telescopes. A great first eyepiece is one about 24mm (20 to 28 is fine). A higher power one with about 8mm of focal length is a good 2nd eyepiece. Make sure that it has enough eye relief for your comfort. Eventually you may want to add a third eyepiece splitting the difference between the two that you have (around 16mm). You can find good Plössl eyepieces for as little as about $50 new or about half that second hand or in a bargain brand.
Moderately priced eyepieces with a focal length shorter than about 8 mm can be very difficult to use because most have very short eye relief. This means that your eye has to be right up against the lens to see the full view and that you can't be wearing eyeglasses. If your telescope focal length is short and you need more magnification than 8mm will give, a Barlow lens is a good choice. These are used between the eyepiece and the telescope to increase magnification. The ones sometimes included with starter telescopes are usually throw away items. Expect a good Barlow lens to cost as much as an eyepiece. There are now some 68 degree wide field eyepieces from China which have good eye relief even at short focal length in the $20 to $30 range. They use all optical glass lenses. Off axis performance isn't great but they are much better than the eyepieces included with most inexpensive telescopes.
The best inexpensive finders are optical reflex finders with illumination from a red L.E.D. They have the advantage of letting you point your telescope without loosing your place in the sky. Straight through telescopic finders are very hard to use. Finders with the eyepiece at a right angle to the tube are much easier to use, but too costly for a beginner telescope.
Barlow lenses can increase your telescopes effective focal length and focal reducers can increase your field of view. Even good ones trade these effects for reduced image quality. The Barlows bundled in some starter telescopes are poor quality. Expect a good one to cost as much as a good eyepiece.
If you will be using your telescope away from your own home, a protective case or bag is worthwhile. You can make your own.
At a moderate price point of less than $400 I do not recommend any electronic features in a starter telescope. The inclusion of these items means that the quality of your optical tube and mount will be lower and it is unlikely that the electronic features will work very well or last very long.
Learning to find your way around the sky yourself is an important skill for a beginner to learn. It's easy to find pretty astro images with little effort on the internet. Automated Go-To or Push-To features that work well can be very helpful in finding dim objects in light polluted urban skies. You may want a good one eventually, but you will appreciate the better optics and mount that you can get without expensive electronic features in a starter telescope.
A reflecting telescope on a Dobsonian mount is your only realistic choice in an inexpensive telescope. A tripod alone capable of holding a small telescope steady will run from $100 to $400, that cost has to come out of the optics in an inexpensive scope bundled with a tripod. Inexpensive telescopes with equatorial mounts will bundle a poor quality optical tube along with a poor quality mount. Refractors in this price range will give dim images with color aberrations. Any electronic features will come at the price of optical quality.
The optics of most moderate cost telescopes are made in a couple of factories in China and are of consistently good quality. Dozens of manufactures take these same mirrors and lenses and put their own name on them. The only real differences are the name, colors, and accessories that they are bundled with. The examples below are ones that I have some personal knowledge of. You may find a better deal on something equivalent.
The Celestron 76mm FirstScope is a table top single arm mini-Dobsonian telescope that is very inexpensive at about $50 list. It's occasionally less than $40 on sale. You will probably want to replace the low quality included eyepieces. It has a spherical mirror which reduces off axis image quality, but still gives very nice views at a very low price.
The Orion FunScope 76mm TableTob Reflector is a similar telescope with a spherical primary mirror at a similar price. Meade's EclipseView 82/300 Dob runs around $140 and includes support for solar viewing. Meade's LightBridge Mini 114 mm sells for about $150.
Replacing the included eyepieces is an easy and significant upgrade. For about $25 a 25mm Plossl like the Orion Serius line makes a great main eyepiece for the FirstScope. 25mm is about the longest focal length that you can use in a small reflector like this without having a noticeable mirror shadow. The included 4mm eyepiece relief is much to short to be useful. I've found SVBONY 68 degree ultra wide long eye relief eyepieces at 15 and 6 mm focal lengths which are a good match for this telescope for a similar price on eBay. Off axis aberrations are noticeable, but acceptable at this price.
Like all Dobs, an inexpensive Alt-Az mount allows the manufacturer to provide a solid, easy to use, mount, along with fairly good optics, at a reasonable cost. A table top mount limits use to where a table is available. If you have a sturdy tripod it's easy to make an adapter that can mount the FirstScope on a camera tripod in either an Alt-Az or an equatorial orientation for easier star tracking. I've written a guide to making a simple adapter.
At this price level you will find larger aperture parabolic primary mirrors. These will have brighter images that show less distortion at the edges of the field of view than less expensive telescopes. The included eyepieces will get you started, but upgrading them is easy and will give you a wider clearer view.
A good step up from the FirstScope is the larger table topAstronomers Without Borders OneSky telescope. The OneSky gives brighter higher quality images than the FirstScope while still being more portable than a full size Dobsonian telescope. Read the Sky & Telescope review.
A full size Dobsonian with a 6 to 8" primary mirror is an excellent starter telescope. They are well suited to both solar system and deep sky visual observation. There are many vendors (Celestron, Explore Scientific, Meade, SkyWatcher, ...) selling full size Dobsonian telescopes with high quality Chinese optics in the $300 to $400 range. My first good telescope was a second hand Orion 8" XT-8 200mm Dobsonian.
Many people want a beginner telescope that they can use for astrophotography. You can take afocal images of the moon and bright planets with any telescope. Afocal images are taken with the camera lens at the eyepiece in place of your eye.
Newtonian reflecting telescopes often do not have enough back focus range for prime focus photography. Dobsonian mounts are not easily adapted for motorized star tracking. Images that require long exposures are easiest with kinds of telescopes: refractors, catadioptric, and astrograph reflectors with precision tracking mounts. These are not good telescopes for beginners because of complexity and cost.
If you are interested in astrophotography, start with some afocal shots of the moon and Jupiter with a telescope. For deep sky images a conventional camera lens and a tracking mount is a great way to get started. These will give you a chance to learn the low light photography and post processing skills that are required as well as making some beautiful images.
You may find that camera lenses work well for the images you want to take. If you not, you will have the experience to choose a telescope for your astrophotography. Find out how in my guide to getting started in astrophotography. You can also read about how to make a simple camera phone adapter that will make taking afocal images with your starter telescope easier.
You will find nearly as many different opinions on beginner telescopes as there are amateur astronomers. Try out some at a local star party. Google is your friend for finding other opinions. You can check out other telescopes that I own and enjoy. For more comprehensive information on choosing a telescope, Starizona's telescope tutorials are excellent and include a guide for choosing a telescope. In book form, The Backyard Astronomer's Guide is an excellent source of information on choosing and using equipment for amateur astronomy. Here is their on-line guide to The Best Beginner Telescopes (under $1000).
Content created: 2019-03-19 and last modified: 2019-12-24
By submitting a comment, you agree that: it may be included here in whole or part, attributed to you, and its content is subject to the site wide Creative Commons licensing.