have an 8" LX200 GPS telescope ... and use a 2" star diagonal (and
1.25" adapter) with a 2" e.p. and a 1.25" e.p.
My question is this: with that setup will adding on a focal reducer
allow me to see a wider section of the sky, or is it as wide as it's
going to get with using just the 2" diagonal.

Hi:

Bit of confusion here...

The 2" diagonal will allow you to see a bit wider field only because 1.25"
eyepieces at long focal lengths are limited by their barrel diameter. So, yes,
you get a bit more true field with a long focal length 2" eyepiece than a 1.25"
one.

OTOH, an f/6.3 r/c will deliver lower magnifications and wider fields with ALL
eyepieces (you will need to stay under about 30mm with 2" eyepieces to avoid
vignetting).


Peace,
Rod Mollise
Author of _Choosing and Using a Schmidt Cassegrain Telescope_
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