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Old 13-08-2006, 01:32 PM
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Hitchhiker
knows where his towel is

Hitchhiker is offline
 
Join Date: Oct 2005
Location: Maitland, NSW
Posts: 371
Hi Eric, image scale is dependent on Focal Length. The longer your focal length, the smaller your Field of View.

The focal length of your 200mm F4 reflector is 800mm.

The focal length of your 80mm F11 refractor is 880mm - your refractor gives you a smaller FOV than your reflector (as you have just found out)

As another example, an ED80 (80mm F7.5 ? ) has a focal length of 600mm and would give you a larger field of view than your 200mm reflector.
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