Expert: Paul Wagner - 8/22/2006

Question

  
   what is the most power you can get out of a 10" reflector
telascope? and fare should the mirrors be apart?  

Answer
Dear Jody:

There is practical answer to these questions, and a theoretical answer.  The practical answer is that you can usually use about 350-500X on a ten-inch telescope, and the primary mirror is usually about 50-80 inches from the eyepiece.  

SO that is the practical.  The theoretical answers are a little more complicated.  If you use a Barlow lens and a very short eyepiece, and you have a long focal length telescope, you can probably create a situation that would get you more than 1000X with a ten-inch scope.  But bear in mind that the image quality will so blurred by atmospheric turbulence that it won't give you any satisfaction.  Basically, it will be like looking at a blurry photograph.  You can magnify that photograph all you want, but the detail won't get any clearer.  That's why the maximum is usually between about 35-50 times the aperture.  

And yes, you could create a very long focal length mirror that would need a much longer tube--but that just creates more problems for mounting it in a stable platform.  The easiest and best mounts are for smaller, more compact scopes that don't weigh so much.  Longer spaces between the mirrors make this a lot harder.

hope that helps.

Paul Wagner