NavList:

I wrote earlier:
"These positional errors are  directly proportional to the distance in
time from the year  2000"

Incidentally, I previously speculated that the error was a sign  error in the
calculation of the proper motion for SHA. It's not. It's  simple though and
still proportional to time. I'll leave it as "an exercise for  the reader" <g>
to figure out what's actually wrong.

And once  again, this little historical issue in no way affects the use of
this software  for present-day navigation. Even in the year 2040, the two
largest errors in SHA  would amount to only 0.6 n.m. in a position line for an
Arcturus sight, which is  the second largest error I've seen, and 4.4 n.m. for
Rigil Kentaurus, which is  the largest by far and an exceptional case (closest
bright star, largest proper  motion).

-FER
42.0N 87.7W, or 41.4N  72.1W.
www.HistoricalAtlas.com/lunars 


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