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Old 28-07-2013, 12:38 PM
ausastronomer (John Bambury)
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Join Date: Mar 2005
Location: Shoalhaven Heads, NSW
Posts: 2,620
Quote:
Originally Posted by Satchmo View Post
You're probably enjoying about 70mm of aperture there but they can't take the wide field away from you ...
In fact running the numbers and making an assumption of 50 yrs of age and a 6mm maximum pupil dilation, the scope effectively becomes a 75mm/F6.67 scope. Plenty of wasted light going west there. Even with a 6.5mm maximum pupil dilation the scope becomes an 81mm/F6.1 scope

Cheers,
John B
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