While doing outreach over the last several years at events ranging from star parties organized by local astronomy clubs, to university or observatory outreach events, I've often gotten questions regarding what telescope to buy for a beginner. The variety of telescope types, brands, and ad claims in the market can be quite daunting to someone who is unfamiliar with astronomy, so I'll try to keep this simple and I'll gloss over a lot of details. Please feel free to email me if you have questions, I'm happy to help. As such, I'll only put down a few recommendations here for people getting into astronomy and want to buy a scope. My first piece of advice is ... don't! Get binoculars.

Get binoculars. That's the best beginner advice I can give. Many people even already have binoculars and a good pair for astronomy can be found for around $100-200, though as with all things, you usually get what you pay for. Binoculars can show you a remarkable number of things and they're easy to use. There are some excellent books written just for binoculars too.

Almost any binoculars can be used for astronomy, but the best all around units are around 7-10x magnification and 40-50mm aperture. This is enough magnification to reveal details, but still low enough to be reasonably steady when hand held. The magnification and aperture of binoculars are usually designated as (magnification)x(aperture), so for example 7x50 binoculars would have 7 times magnification and 50mm aperture lenses.

If you're looking to buy a pair of binoculars for astronomy, stay away from zoom units. It might sound like a good idea to be able to zoom in on your target, but you usually sacrifice image quality to get the zoom ability and you end up with a complicated mechanism to zoom the binoculars which can break. Stick with simpler units that work well at a single power.

Once you have a good pair of binoculars, you need a guide to tell you where to look. One book I can recommend is Binocular Astronomy by Crossen and Tirion. I observed for several years while in college using only binoculars and that book. Two other books which I have heard positive things about are The Binocular Stargazer by Leslie Peltier and Touring the Universe Through Binoculars by Philip Harrington.

Two vendors which I have bought binoculars from and have had good experiences with are Stellarvue and Orion Telescopes and Binoculars.

Okay, now you've learned a little bit about the sky using naked eye and binoculars and you are ready to take the plunge and buy a telescope. There are a lot of different types of telescopes out there with a lot of different options and it can be intimidating to browse through catalogs and web sites. How can you figure out which kind of telescope is best for you, let alone which particular brand and model?

The most important advice I can give is to buy a telescope from a vendor who knows something about astronomy. There are a whole class of telescopes that amateur astronomers refer to as "department store telescopes" which are sold by various general retailers. They are usually cheap ($100-$300) and have flashy packaging which advertises the high magnifications possible in the scope. WARNING: These telescopes are almost always junk! Poor optics combined with shaky mounts mean that the telescope is hard to use and will do more to deter your interest in astronomy than to grow it. The old adage of "you get what you pay for" still holds and a telescope which seems like a great deal because it is so cheap is probably not worth it. Many scopes sold for $99.95 at department stores can be bought in bulk for $10-20 per unit and that is their real value. If you're lucky enough to have a store nearby with astronomy savvy employees and good telescopes available, then you're in the minority. Most of us buy off of the internet so I'll try to include a few links as we go.

To narrow down the selections, I would first recommend that you forget about computerized telescopes. They seem like a good idea in that they will find things for you, but when you buy a computerized go to telescope, you end up paying for the computer and you usually get a lesser telescope. If you've learned the sky with binoculars, then finding relatively bright objects should be a straightforward next step. I've seen too many frustrated people fussing with a cheap computerized telescope in the dark to recommend them to beginners. Even if you can only find a couple of objects yourself, at least you're looking at something rather than arguing with a finicky computer late at night in the cold and dark. Computerized scopes also require power, so you're either tethered to an outlet or you're carting batteries out into the field and batteries often don't perform well in the cold.

To further narrow down the options, I recommend only two basic types of telescope to beginners, either a small refractor or a simple dobsonian reflector. These designs have one big advantage over the third common telescope design which is the cadiotropic (e.g. Cassegrain, Schmidt-Cassegrain, Maksutov, etc.), they have shorter focal lengths (smaller f-ratios) which means that you get a wider field of view, which makes finding things easier.

I'll detail both of the options I recommend in the sections below, so you can decide for yourself what is best.

I like the small refractor as a beginner scope. It is easy to use, requires little or no maintenance or adjustment, it delivers excellent planetary views, and is very portable. The disadvantage of a refractor is that you get relatively little aperture and thus less light gathering power. Additionally, some refractors (known as achromats) show "chromatic aberration" which means that the blue light is poorly focused by the lens. This will show up as a blue halo around bright objects. This is not terribly objectionable in my opinion, but if it bothers you, then an achromatic refractor is not for you. You can get apochromatic refractors which do not show this, but they are fairly expensive, so I won't discuss them further as a beginners scope.

One disadvantage of a refractor is that there are many poorly made ones. A poorly made (often imported) refractor will work fine for wide field views, but the image may not be sharp at high powers. The biggest problem with these cheap refractors is that there are variations from unit to unit. If you buy one, you may get one with well aligned optics which performs well, or you may get one with misaligned optics that cannot be used to reveal the same detail at high powers as a properly aligned unit. Another problem with these cheaper refractors is that the "clear aperture" (the actual light gathering power you get in practice) may be less than what is stated because of poorly placed baffles or focuser draw tube. With these caveats you can still have fun with a relatively large aperture (100-152 mm or 4-6 inch) imported refractor which costs a few hundred dollars.

My preference is to opt for a well made achromatic or "ED" refractor. You will get somewhat less aperture for the same price, but the telescope will be well aligned and will provide sharp views at high power. In addition, if you stay in the hobby and eventually get a large telescope, a small, high quality refractor is still useful. Many amateur astronomers (myself included) have a large telescope which we take out on occasion and a small refractor which gets used more often as it is easier to take out on a moment's notice. Such a convenient "grab-and-go" telescope will stay with you for a long time. Whereas a lower quality telescope may soon be replaced if you become enthusiastic about the hobby.

My preferred maker of small refractors is Stellarvue. I've owned three of their telescopes and all have performed superbly.  A good refractor can be found for $300-600. 

With a refractor, you will probably need to purchase a mount in addition to the telescope itself. There are two basic options, an equatorial mount, which can be aligned to track the stars for you, and an alt-az mount which has simple up-down and left-right motions. Unless you are planning to do a lot of very high power viewing, I recommend the alt-az mount because it is usually lighter, simpler to operate, and requires no alignment. The disadvantage is that you will have to continually nudge the telescope to keep the object you are viewing centered at high power. For a good mount and tripod you can expect to spend about another $400 in addition to the cost of the telescope itself.

An alternative to the refractor is the dobsonian (dob) telescope. A dob is a very simple design and as such you get a lot of aperture for your money. In the roughly $400 range (similar to the high quality refractors mentioned above), you will get an 8 inch dobsonian (200mm aperture).  This gathers quite a bit more light than the 80mm refractor, but the dob has some disadvantages. First, the dob is bigger and more awkward to move around. If you are doing all your observing from your driveway or if you have a big car to carry the dob, this is no big deal, but if you want to pack the scope and the family all in a modest car it starts to become more of a squeeze.

Second, the dob requires collimation. This means that if you want to get good image quality, you have to align the dob's two mirrors with one another. This is true at both low and high powers. The collimation procedure is not hard, but can be intimidating at first. My first real telescope was a 4.5 inch reflector and I was too scared to collimate it myself for a long time. I still enjoyed using it, but I never got decent image quality out of it until I was willing to learn to collimate. If you want to learn more about collimation, try one of these websites.

The advantages of the dob are that you get more aperture for your money as mentioned above. Also, you don't have to buy a mount! The beauty of the dobsonian is that the mount is part of the telescope itself. It's an alt-az similar to what I recommend for the refractors, so it is robust and easy to use.

If you're interested in dobs, there are a lot of vendors. Inexpensive dobs in the sub-$1000 price range as I've discussed above are usually decent, but may not be perfectly sharp when used at higher powers. There are several brand names under which these scopes are sold (most are made overseas). One brand which has a decent reputation is Orion Telescopes and Binoculars.

One final note about dobs that I should make is that they are unsuited to daytime observations. You can't use them as a spotting scope for wildlife or scenery the way you can with a refractor. If this matters to you, you should probably not opt for a dob.

It is important when buying a telescope to budget for other accessories that you'll need. Most important are eyepieces. These are the optics that allows you to look at the image that the telescope forms. By changing eyepieces you can change the magnification and either enlarge the target (high powers) or look at a wider field of view (low powers). Many people make the mistake of assuming that you always want more magnification, "higher power is better, right?" No. In fact, you want to use a magnification which properly frames the objects you're looking at and still shows detail. Many objects are best viewed at low powers. Except for the planets, you'll usually be below 100x.

The magnification which you get out of a particular eyepiece is determined by the focal length of the telescope divided by the focal length of the eyepiece. For example, if I have a 750mm focal length telescope and a 25mm eyepiece, that gives me 30x magnification. A 10mm eyepiece with the same telescope gives 75x.

There are a host of eyepiece designs and brands to choose from and it can be confusing. As with all things, you get what you pay for, so expect to pay roughly $50-$100 for a decent eyepiece (you can spend far more if you want to). A safe bet is to get the plossl design of eyepieces, they are a good all around design. Another popular option is the host of "wide field" designs which have larger apparent fields which shows you more sky at a given magnification. Those vary in quality and can be very good, but you'll give up some sharpness in others.

There are also simpler designs of eyepieces which are not very popular today. They often have narrower apparent fields, but can often be sharper and have slightly better contrast than the more complicated plossl or wide field designs. These are often considered better for planetary viewing, but they also give and edge in contrast to deep sky objects as well. I can recommend the orthoscopic design and also the Edmund RKE brand. In fact, I have a set of Edmund RKE eyepieces for some planetary viewing and if I'm looking for maximum transmission and contrast. They cost about $55 each though they have a slightly narrower field than traditional Plossls.

In addition to eyepieces, you'll need a good red flashlight at night. A dim red light does not affect your night vision the way a white light will, so these are a necessity, especially if you'll be in the company of other amateur astronomers. These can be a simple as red cloth or plastic taped over the end of a regular white light, or a dedicated astronomy light with red LED lights and brightness adjustments.

You need a good guidebook or chart to help you figure what to point at. One very basic reference which I still use frequently is the Bright Star Atlas by Wil Tirion. It divides the sky into about a dozen charts which are easy to match up with the naked eye sky. This book is primarily charts and tables of objects, but makes an excellent reference.

Another good reference book for small telescopes is the Binocular Astronomy book I mentioned above. It includes the charts from the Bright Star Atlas, but also describes good binocular objects on a constellation by constellation basis. Of course, objects which look good in binoculars often look even better in low to medium power telescopic views which makes this a great book for small telescopes as well.

The last book I'll recommend by name is The Year-Round Messier Marathon by Harvard Pennington. This book describes the 109 Messier Objects (a list of some of the showpiece deep sky objects). It gives an excellent general introduction to the techniques astronomers use to find objects and gives charts for finding the Messier objects. This makes finding these objects easy, even for beginners. There are many other excellent books out there, but these are three which I am familiar with which are also good for beginners.

A good observing site is the best observing accessory. I would rather have a good 80mm telescope at a decent dark site, than a larger scope in a moderately light polluted city. Your local astronomy club will probably know of one or more dark sky sites which balance driving distance and site quality.

If you observe from a light polluted location (as most amateur astronomers do), all is not lost. You can still see the planets as well as you could in dark sky and plenty of deep sky objects are within reach of a modest telescope even with some light pollution. If you do live in an area with light pollution, as most of us do, then I encourage you to check out the International Dark Sky Association (IDA) web site. There are some simple things you can do to help fight this waste in your community.

Another great resource to have is a local astronomy club. Meeting other people who share an interest in the hobby can be quite helpful. You'll get nearly as many opinions on gear, accessories, and observing sites as you find people in the club.

If you don't have a club nearby, you can participate in on line discussions with astronomers from around the world. Two of the largest on line communities are in the forums at Astromart and Cloudy Nights.

I hope this has been a useful resource. There is a lot of information here and I hope it's not overwhelming. Astronomy can be a very rewarding hobby and there is definitely a friendly community of amateur astronomers which I hope you'll join. If you have any questions please feel free to email me, I'm happy to answer questions.