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Outbackmanyep
20-12-2007, 10:15 AM
http://www.stargazing.net/naa/scopemath.htm

I found this link most interesting, see what you guys/gals think!

Cheers!
programmer
20-12-2007, 11:17 AM
Great site. Will be using this in the future I'm sure..
saberscorpx
20-12-2007, 11:27 AM
Gem of a link. Handy and informative.

Coaxing my scopes to perform theoretically is another matter.


SJS
JimmyH155
20-12-2007, 03:03 PM
That was a great link. I'm worried now - if my pupil can only expand to 5.6mm as the link says for my age, does that mean that I should not use an eyepiece with greater than 5.6 mm exit diameter?? What about my Hyperions, they have very large exit - much larger than 5.6 mm?
Am I missing something??:shrug:
JethroB76
20-12-2007, 08:45 PM
Jimmy, exit pupil =eyepiece fl/ f ratio

So in your LB a 21 hyperion will give an exit pupil of 21/5=4.2

Something like a 30mm is probably the upper limit for you on this scope, in terms of exit pupil.
JimmyH155
21-12-2007, 11:33 AM
PHEW!:)
Thanks for that, Isdonisgood. I thought I would have to ditch the Hyperions (I have 8 mm and 13 mm) which I love:D:thumbsup: