Large Dobsonian Telescopes
Friday, May 11th, 2007
The least expensive way to get a good sized telescope for some magnificent night sky viewing is to purchase a dobsonian reflecting scope. Most amateur astronomers start off with a 4 inch reflector on a standard tripod mount. This does get your feet wet but it becomes apparent, after a while, that you can’t see too much beyond planets and a few bright deep sky objects.
Dobsonians use a ground base with a set of ball bearings that maneuver the scope into position. These can be a lot easier than the traditional mounts unless, of course, you have a pricier electronic controlled one.
Bigger telescopes can get quite pricey on a tripod mount. The construction has to be of much higher quality the bigger and heavier the scope gets. Enter the dobsonian design. These can be produced much cheaper and and use lighter weight materials. The biggest cost involved is the mirror rather than the hardware.
The amount of light received and the thus the view and detail you get is exponentiated the larger the mirror surface. Deep sky objects such as galaxies and nebulae will look a light crisper and bigger through the larger scopes. This will give you a lot more to look at and observe and not limit you as much as a beginner telescope. The closer objects will be good subjects, too, even when atmospheric conditions are low.
Several companies manufacure the dobsonians but you don’t often see them displayed in retail outlets. Meade, Celestron and Orion all have decent ones at reasonable prices. Expect to pay about half of what you would for a tripod mounted version and a lot less than a refractor or cassegrain model.
Here’s one example of a relatively inexpensive model from Celestron:
You can get bigger ones such as this:
Check around and see what size fits your budget and tastes. A whole new world in astronomy opens up with these bigger telescopes.