Cool Telescope design
From
Slashdot.
When you want to make a telescope with a large diameter primary mirror, there are some mechanical and optical issues that make it very advisable to make the telescope have a longish focal length (f6 to f8). For a scope with an 18" diameter primary, this could mean a tube length of ten feet.
For a Newtonian design, the eyepiece is out at the end of the tube so a 10' tube length will make observation tricky - mechanical stability of the tube also means that the scope will be heavy.
What Michael has done is instead of having the Newtonian eyepiece at the end of the tube with the small mirror at 45 degrees, he has used a larger mirror angled at 15 degrees and folded the eyepiece tube at an angle to the main tube.
The
pictures here explain it better than words.
Cool idea!
Posted by DaveH at February 3, 2004 9:18 AM