From: "Bob May" 
To: "atmlist" 
Reply-To: "Bob May" 


Shorter FL mirrors are more sensitive to the vertical displacement of the
source to KE but that sensitivity tends to make the shadows move vertically
as they darken more than anything else and that tends to be easily observed
for what it is more than anything else. The putting of the lens close to
the KE is a bigger requirement for the short FL mirrors as the light cone
quickly exceeds the ability of the lens to capture the edges of the mirror
- pull your eye back from the KE while viewing the mirror and the same
thing is happening. Bob May
http://nav.to/bobmay
bobmay{at}nethere.com
NEW! http://bobmay.astronomy.net

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