NavList:

Hello all,

 

I tried a Lunar experiment on December 1st and 2nd 2008.  Here in South Korea, in the evening twilight, we had a nice tight configuration of the waxing crescent moon and the planets Venus and Jupiter which were very close together.  While I know that it is poor practice to shoot Lunar Distances that are "close" I wanted to see what kind of errors I would get shooting close lunars with different bodies in close relative proximity.

 

I have attached a couple of pdf files (they are small) with the raw data sheets  for each night (including a picture of the three bodies) along with the computed lunars of the average of both bodies for each day.  The data sheets are not well labeled as i use them primarily for obtaining averages and then individual sight errors.  I am including them mostly for the photographs.

 

The two sets of lunars are shot nearly exactly 24 hours after each other, give or take 30 seconds for each average.  Each set is a five-sight average between the moon and Venus and then the moon and Jupiter.  In the first set, the moon was west of the planets and a far limb lunars were shot.  The next night the moon was to the East of the planets and near limb lunars were shot.  I found that the calculated error was very close between the two planets each night, and the observed distance was nearly double for each body from one night to the next.  As the distance was about twice as much, the error was half, and in the opposite direction the second night.  The errors are too great to make much use of the lunars for anything but an academic exercise however.

 

I am sure that those more versed in the theory of these sights can expand on why the data did this.  Then again, perhaps, it was me having a bad night with the sextant.

 

Jeremy