NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Brad Morris
Date: 2014 Mar 28, 20:17 -0400
Randall
Just a question. You stated that two of the altitudes were over 100°. I assume you mean a doubled altitude when using the AH. I don't understand how you can do a back sight with an AH
Brad
On 25 March I gt a 10 body run of sights with and averaged a=0.67 from GPS. Two were altitudes over 100 degrees and without these the 8 sight average was a=0.34 from GPS. Bodies shot were Sirius, Rigel, Aldebarran, Capella, Mirfak, Dubhe, Regulus, Alphard, Adhara and Alnilam. Just some "observations" about chasing accuracy:
Brightness of the body does not sem to be a factor. Alnilam was a=0.0 and so was Capella.
Being really careful with focus does seem to make a difference. You have to split the diffeence between perfect focus on the mirror body and on the sky body. Careful attention to focus balance between the two seems to help.
Being very "honest" about your subjective decision about when youe mark the instant of tangency or coincidence is very important. As you make those final rocks and micrometer drum movements think of it like shooting a gun. Are the sights really on the target or do you think they are? I believe this perception of that is likely the most important factor. If it does not "feel" right, take the scope from your eye, relax and shoot again. Results will likely improve.
My obsetrvations are not based on knowlegde, but lots of experience taking sights. Have fun.
Randy
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