Next message: Joel Jacobs: "Re: French Sextant"
Go to this page:
mysticseaport.org/library/initiative/PageImage.cfm?PageNum=160&bibid=34575
It's a journal entry from March 26, 1825. It shows one complete lunar
distance calculation done by hand with a standard approach from that period. This is
the raw "scratch" work done on an empty page in the back of the book with
almost no labeling, and if you don't know lunars from stock prices, you might
never guess what you were looking at.
At the top of the page it says March 27 Sea Account and there's no year given
that I can see, but this journal includes entries in the early to mid 1820s
so it was a simple process of elimination. By using my lunars almanac (the
"Lunars Predictor" on www.HistoricalAtlas.com/lunars ), and setting the time to
Greenwich Apparent Time, it was not too hard to find the date that closely
matched the entries from the published Nautical Almanac which are marked on the
right hand side of the page.
But note how short this calculation is: a lunars calculation AND the
corresponding time sight all on one page with plenty of room to spare!! These things
were NOT difficult, and they were not time-consuming.
So here's the fun part: which method is this navigator using to clear his
lunar?
Frank R
[ ] Mystic, Connecticut
[X] Chicago, Illinois
