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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: How does the AstraIIIb split mirror work?
From: Fred Hebard
Date: 2004 Apr 23, 17:43 -0400
From: Fred Hebard
Date: 2004 Apr 23, 17:43 -0400
On Apr 23, 2004, at 5:14 PM, Ken Muldrew wrote: > > Because the light coming down from the index mirror is not > perpendicular to the horizon glass, the reflections from the front > surface and back surface will be vertically displaced, due to the > horizontal displacement. The reflected rays will be parallel, but > displaced vertically. I just got a piece of plexiglass (9mm thick, > but close enough) and verified that. By changing the angle of > incidence, one can change the separation. One reflection is > significantly brighter than the other, but they are both clearly > visible. I don't see that in a sextant. I've seen it. Fred
