Telescope Basics

First, some of the most common questions:

What is the best telescope?
You will hear hundreds of answers to this question depending on the various observers' preferences. Quite simply, the best telescope for you is the one that will get used and enjoyed often.

OK, so which telescope should I get?
There are 2 basic types of telescopes; the reflector and the refractor. Some folks talk about a third type - the catadioptric. A cat is actually a combination of a reflector and a refractor.

Reflectors use a pair of mirrors to collect and focus the light. The primary is the large mirror at the bottom of the tube (typically in sizes from 3" to 40"). The light is bounced off of the primary and reflected back to the top of the tube off of the secondary to the eyepiece. Reflectors are generally preferred for deep-sky objects such as nebula and galaxies. They also offer excellent high powered viewing of the planets and moon. One often sighted disadvantage of reflectors is their maintenance needs. They require collimation of the mirrors for the best images possible which can be accomplished relatively easily with reading and the right tools. In its simplest sense, collimation is the process by which you align the primary and secondary mirrors.

Reflectors are typically offered on 2 types of mountings, the Dobsonian and the German Equatorial Mount (GEM).

There are several options out there for Dobsonians. Celestron, Discovery Telescopes, Meade, Orion and Starsplitter all offer reasonably priced options. My personal preference would be the Starsplitters. These scopes are a step up in quality from the others and are a joy to use. The advantages of this type of scope are the largest aperture per dollar, portability, and simplicity of use. The disadvantages are the lack of slow motion control , which can be very beneficial in high power viewing and the inability to do astro-imaging.

Another type of reflector mounting is the German Equatorial Mount (Gem). This is typically more expensive than the Dobsonian. It is somewhat more complex to set-up and use, but offers the advantage of slow motion control and the ability to add motor drives. While there are many choices in this category, as I am gearing this towards beginners, I will offer only a few suggestions. Currently the scopes availably with quality mounts are the Celestron 114HD (4.5"), the Orion Skyview Deluxe series, and Discovery . The prices on these scopes range from $379 for the 4.5" models to $599 for the 8" Discovery. My personal recommendation would be one of the Orions.

Refractors focus the light through a lens in the front of the telescope to the eyepiece in the rear of the tube. A decent refractor is significantly more $ per aperture than a reflector. Refractors have the reputation of providing the sharpest views of planets and the moon.

Advantages of refractors are that they are virtually maintenance free, and offer excellent images. Their biggest disadvantages is the cost and the limit of aperture sizes available.

Many amateurs have started out using a 60mm Refractor. Fortunately, there are some very good refractors now available that won't force you to get a second mortgage. The Celestron Firstscope 60 deluxe, the Celestron C102-HD and Orions 90mm Deluxe. Starting at less than $150 (for the Celestron FS60 Deluxe), we finally have a useable telescope available for those wishing an inexpensive entry into the hobby. While the limitations of 60mm of aperture will quickly show themselves on deepsky objects, this little gem performs very well on the moon, planets and large bright deep sky objects. Also, there are currently some relatively inexpensive (<$300) rich field refractors which perform marvelously on large objects such as star clusters. The 2 in this category I would recommend are the Orion Short Tube and the Celestron 80WA.  All of these scopes are manufactured by Synta in China and can be found under various brand names, Omcon, Skywatcher among them.   There has also been a recent addition to the low priced refractor market.   Marketed under several names, it's a 150mm (6") scope.  I would not recommend this scope to anyone looking for a scope to be used out of the box.  The mount is grossly inadequate and will cause more frustration than joy under the stars.

Catadioptrics are the workhorses of today's amateurs. The most common types of Cats are Schmidt-Cassegrains and Maksutov-Cassegrains. They are highly versatile instruments are are often preferred for astrophotography. There are thousands of available accessories for these scopes, such as digital setting circles, computer controls, etc. These allow you to simply align on a couple of known stars, and program the scope to point to whatever you want to find. While this may sound like the perfect option, the disadvantage is that you may never learn the sky with this method.

Catadioptrics are available in 3" to about 24" (the largest I've seen). They offer excellent portability, and lower maintenance than a reflector. Over about 10" though, the portability is questionable at best (typically about 100 lbs.). The price range for Catadioptrics starts at about $595 for a 3.5" Meade ETX (a Maksutov Cassegrain), all the way up to as much as you wish to spend. A good 8" basic model (such as the Celestar 8 from Celestron) is about $1000.

Another key consideration in selecting a scope is where it will be used. Will you be able to set it up and leave it in your back yard (protected of course), or do you have to carry it down several flights of stairs just to use it? Will you be driving out to a site to observe with it? For portability, anything larger than an 8" Equatorial mounted Reflector, a 10" Dobsonian, a 10" Scmidt-Cassgrian, or a 5" refractor is about the limit for most people. (Although Arnold Scharzenegger may disagree). Add to this equation the size of your car, and you can very easily see what scope will be portable enough for you.

If portability is your number one concern, the Celestron G-3 or G-5, Meade ETX, or the Orion and Celestron Short tube refractors are excellent choices. They are highly portable and offer very good imagery.