<blockquote><font class="small">In reply to:</font><hr /><p>I thought that refractors was for the moon and cost cheepist and cassegrain was for deeep objects and cost the most and the reflector was for middle and cost avrage....<p><hr /></p></p></blockquote><br /><br />Refractors are the most expensive <i>per inch of apeture</i>. It's hard to make big lenses, basically. But you won't find a one-inch reflector; the refractor is superior, and at that scale, easy enough to make.<br /><br />But as you get bigger, refractors get harder to make, so you go to reflectors. The classic reflector design is the Newtonian. This gets you by far the most apeture for the dollar. These are arguably the most economical telescopes, especially the Dobsonians, which have an inexpensive mount. Many large home-built telescopes are Dobs. A Dob is a Newtonian telescope with a mount on the bottom end that sits directly on the ground, rather than an expensive tripod with an equitorial mount. (Drawback: you can't get a clock drive for a Dobsonian, so you'll have to move it manually to track objects in the sky.)<br /><br />One of the big problems with Newtonians is that the eyepiece is near the aperture, and it's perpendicular to the telescope tube. This can make it somewhat awkward to use. They're also long and bulky. A twenty-inch Dobsonian will be taller than you are (although I have seen collapsable tube designs which are somewhat portable). So some favor the Schmidtt-Cassegrains reflectors. These fold the light path back on itself, halving the length of the tube and also moving the eyepiece so it's coming out the back of the telescope, much like a refractor. They're much less bulky, easier to steer, and a bit less un-ergonomic. But they also cost a lot more per inch of aperture. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em> -- The Tenth Doctor, "Blink"</font></p> </div>