NavList:

Bruce,

While you were posting your latest message, I was in the middle of running your numbers. Again, the easy way to do this is to visit the USNO calculator site here:
http://aa.usno.navy.mil/cgi-bin/aa_flamenav.pl
Enter your position, and then the time for each sight in succession. You'll get the Hc for the Moon and also the "Sum" altitude correction. But that sum is for a Lower Limb sight. You have to subtract 2*SD from that. That is, calculate (90°-z.d.)+Sum-2*SD for each sight. Then compare against the Hc. The difference between the two can either be interpreted as the intercept for the LOP or more simply as the error in the observation. For each of your observations in turn, I get Ho-Hc equal to -0.2,+0.25,+0.3,+0.3,+0.15. Oh, but there's one more very small correction to the Moon's altitude, usually ignored. It's called the "oblateness correction". Sound familiar? In the case of these observations, it looks like we need to subtract .15' (or so) from each Ho. That gives us a new set of Ho-Hc values: -0.35,+0.1,+0.15,+0.15,0.0. The mean error is basically zero and the standard deviation is roughly 0.2'. Pretty good then! ...as one would expect for theodolite observations.

By the way, you can certainly do time sights with Moon observations, but I can't think of any good reason why you would want to! Use the Sun for time sights. :)

-FER

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