Image of the day

Captured by
John Roach

Enhanced Uranus showing Polar Cap and possible Aurora

My Account

New to Astromart?

Register an account...

Need Help?

parabolical mirror

Started by claymuck, 04/01/2004 03:09AM
Posted 04/01/2004 03:09AM Opening Post
What can any one tell me about the parabolical mirror such as there pro's and con's..also interested in your experience with them....
Posted 04/01/2004 02:06PM #1
Assuming you're talking about Newtonians, paraboloids are the only way to go unless you're talking extremely long focal ratios in which case a sphere will work. Plus if you want a sphere then you must go longer with increasing aperture. For example, a 4" f/10 sphere is "diffraction limited" but an 6" f/10 sphere is not. The bottom line is that at most practical apertures and focal ratios the paraboloid is the only game in town.