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    Re: Lunar distance sights
    From: Frank Reed
    Date: 2013 Apr 23, 19:05 -0700

    Hello Randall,

    I just did a quick review of some of your earlier posts to remind myself of what sorts of sights you've taken, the instruments you've used, and so on. Here's a link to all your messages in case you're in a nostalgic mood!: http://www.fer3.com/arc/sort2.aspx?y=201108&y2=201512&subject=&author=morrow

    Certainly your Astra IIIB with a 7x telescope SHOULD be able to produce better lunar observations, but it's no guarantee. I have tried four Astras in the past few years. Three gave uniformly excellent results but one yielded observational scatter on the order of one minute of arc. I never found any explanation for it though I didn't have that one very long. Since you're skilled with artificial horizon sights, you should compare your lunars against a run of A.H. sights of a single body --maybe Jupiter since it's conveniently placed in the evenings. If you shoot a dozen Jupiter sights over the course of an hour (so that they're not tightly grouped) and then look at the scatter in the intercepts, is it approximately half the scatter you see in your lunars? Artificial horizon sights are nearly identical to lunars in most respects except the discomfort from some odd angles. Note that the full angle (double the altitude) measured in an A.H. sight should be compared with lunars which is why the scatter in altitudes or intercepts would be half the scatter in comparable lunars. In fact, I actually find that the scatter in A.H. sights is greater than in lunars. I attribute that to the much more rapid changes in the angles, but it might also be that I am just clumsy at those sights.

    -FER


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