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Old 20-05-2018, 01:55 AM
Wavytone (Nick)
BigBanger

Wavytone is offline
 
Join Date: Jul 2008
Location: Killara, Sydney
Posts: 3,811
Back of fag packet calculation gives effective focal length 10,800 mm - making the scope almost f/22. Even worse than I guessed.

In a 2” eyepiece with an ID of 45mm the available field of view is a whopping 14 minutes of arc and a 40mm eyepiece will give 240X - if the seeing allows that much.

Good luck with that - you’re going to need it.
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