76mm Reflector
In Defense Of The Common
76mm Reflector
You've heard of department store or trash telescopes. Sometimes, these are just diamonds in the rough.
One of my favorite telescopes is a 1997 vintage Bushnell 76mm Newtonian telescope that I call "George" (after George Harrison of The Beatles). It is by no means a great instrument. As you can see in the above image, the legs tend to splay perhaps too often if not tightened down firmly. The alt-az tripod leaves much to be desired at times. But optically speaking, George is not that bad an instrument. In fact, where portability is concerned, it is one of my most used telescopes.
76mm Newtonian's are fairly common and usually cheap. They have roughly the same light gathering capabilty as a 70mm refractor. Some of the better known brands (Meade, Celestron, Orion) are optically superb instruments, if a little on the small size.
What To Look For In A 76mm -
Optics
First off, try to go with a major name brand. While my personal experience with "George" has been great, I've found that some other telescopes by this company to be lacking. Fortunately, "George" appears to have been made by the same plant that makes the optical tube assembly (that's the actual telescope in technical terms) for very similar designs from Celestron and Orion (as well as some recently discontinued Meade telescopes). Make sure that the focuser is designed to hold 1.25" eyepieces. The older, smaller eyepieces were .965", a standard that is now widely neglected. You'll find plenty of good eyepieces in the more common 1.25" size.
1.25" and .965" Eyepieces
On the subject of eyepieces. Most telescopes come with two or three eyepieces ranging from 10mm to 32mm. That is a good range and gives you the best options as to what you can observe. It may be tempting to go with eyepieces with focal lengths less than 10mm. Don't. The shorter the focal length, the worse the eye relief. Eye relief can be best described as the amount of difficulty that you have using the eyepiece; in short, is it the distance that you need to be from the eyepiece in order to observe. If the eye relief is poor, you find that you have to get in fairly close, and that isn't very comfortable. If you need higher magnifications, buy a good quality Barlow.
Orion 2x Shorty Barlow
The Other Big Consideration -
Tripods & Mounts
So far, though, we've only covered the optical tube assembly. You can have the greatest set of optics in the world, but if your mount is wobbly, it might as well be a handheld. If possible, check to see how sturdy the tripod is. Fortunately, most modern units use aluminum in their construction. "Georges" as an older wooden one and is a little worn, but when tightend down properly works just fine. On top of the tripod is what we call the head, this being where the telescope is actually mounted. There are two primary types of mountings that you'll find for most telescopes, and this one is no exception; altitude/azimuth (alt/az) and equatorial. The alt/az design is the simplest and therefore the least expensive. For most beginners, this is adequate. Its one failing is the difficulty it encounters tracking objects. This is where the equatorial mount has the advantage. Of course, it costs more but the primary benefit is being able to stay on an object and follow it as it crosses the sky.
Altitude/Azimuth & Equatorial Mounts
The equitorial mount, of course, comes with added costs and usually a lot more weight. The advantages outweigh the disadvantages, though. Some of them are motorized, allowing you to stay fixed on an object.
More than likely, you're going to come across the Alt/Az more often.You want to make sure that the motion is smooth when the telescope swings from side to side and up and down. Loose fittings can make for some jerky motion. Equatorial mounts are almost always better made, but leave nothing to chance. Again, you're going to want to check for mobility.
The Bottom Line
Of course, if you have more money and are willing to go into astronomy with both feet, definitely consider a larger instrument. However, many of these 76mm telescopes sell for anywhere from $75 to $180 USD, and can be fine instruments. If possible, always look towards the major brands such as Celestron, Orion and Meade (Bushnells are also fairly decent). Always ask to see if there is a floor model available to try out the optics. Even if you have larger instruments, a 76mm is a lightweight telescope and is much more portable than, say, an 8 inch/200mm EQ mounted Newtonian. From my experience, "George" has been a great little telescope, one that has provided me with hours of good observing. Don't overlook the humble 76mm. Most are just diamonds in the rough. This page assembled with Appleworks 5 & TextEdit on Macintosh OS X version 10.4.6... honestly!
