NavList:

   

Reply

Jim, you wrote:
"I took the time to interpolate between your first and second Sun and
Moon altitudes. I then used the online calculator using interpolated
values for the altitudes and the time of each LD observation to
determine the error in the observed lunar distances which I found to
be:

3) 1.4
4) 1.0
5) 1.0
6) 1.2
7) 0.9"

But you got these values, Jim, by ASSUMING that these were Far Limb sights,
right? The problem is that Jeremy took Near Limb lunar distances (and when
you're shooting Sun-Moon lunars, that's always the case unless you're trying
something rather exotic). Cleared as Near Limb lunars, the error is around
half a degree. This implies some big "blunder" -- it couldn't be an
observational error. One possibility is recording the time incorrectly on
all the sights. It's surprisingly easy to do this: you write down 7 hours
when the watch says 6 hours because you're thinking about something you have
to do at 7 hours. I experimented a little with Jeremy's sights and could not
find anything like this. The Sun and Moon altitudes are consistent with the
DR location and the UT as recorded. Can anyone think of some other error in
writing down the sights that would lead to an error in all the lunar
distances of just over half a degree?

Jim, something you might get a kick out of: You cleared Jeremy's sights by
interpolating for the exact altitude of the Moon. Try it again with the
Moon's altitude shifted up or down by one whole degree. How much does it
influence the cleared lunar? Lunars near 90 degrees are special this way
 --large errors in the Moon's altitude make little difference.

 -FER
PS: Finally "de-compressed" I should be posting extensively in the next
couple of days.



--~--~---------~--~----~------------~-------~--~----~
Navigation List archive: www.fer3.com/arc
To post, email NavList@fer3.com
To , email NavList-@fer3.com
-~----------~----~----~----~------~----~------~--~---

   

Reply