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Question about Davis Mk 25 sextant beam converger
From: Greg R_
Date: 2006 May 3, 09:05 -0700
From: Greg R_
Date: 2006 May 3, 09:05 -0700
I bought a Mk 25 sextant a couple of weeks ago, and am
wondering about the accuracy of the beam converger (it's a full-horizon model
vs. split-mirror) - from what I can tell so far, the alignment seems to depend
on the distance to the object. I can dial out all of the index error on a nearby
object (say a nearby street light or a rooftop), only to find it's different
when using a celestial object (sun (with proper filtering on both mirrors, of
course) or a star).
Same thing in reverse when aligning it with a star or
the sun, setting it up that way throws nearby objects out of alignment (by
several minutes of arc).
Is there something I'm not understanding about how this works, or is this sextant possibly defective? Thanks in advance for any input, I also e-mailed that question to Davis and I'll post the reply when I get it.
Is there something I'm not understanding about how this works, or is this sextant possibly defective? Thanks in advance for any input, I also e-mailed that question to Davis and I'll post the reply when I get it.
--
GregR
