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Brad, you wrote:
"Bruce Stark, when he was contributing to the list, offered a wonderful 
exposition on how to recover GMT via lunars.  The details are found in a 
NavList posting whose number I cannot remember.  I did keep a file of it 
though, and link it herein.  All the way from not knowing any time to GMT! I 
have not exercised the method and can offer no insight as to how accurately 
one can recover GMT from it. "

Uh, now wait a minute. You measure the angle between the Moon and the Sun (or 
some other celestial body from the list in the almanac). You clear it (some 
math here but not too bad). Then you interpolate the cleared value between 
known values of those "lunar distance" angles taken from the almanac where 
they were printed at three hour intervals of GMT. And that's it. That's all 
there is to it. Bruce's explanation may have obscured that simplicity. Of 
course if you then want to get longitude, you need to compare GMT with local 
time which requires a time sight, but that was a common feature of all 
navigation in that era, not lunars specifically.

Incidentally, while reading the 'doc' file you attacheded, I was impressed 
with the fine description of the time sight which occupies about half of the 
file (just below Bruce's description). And then I realized, 'well, no wonder 
I'm impressed --that's MY post.' ;-)

-FER
PS: If you have some text in your notes that you've taken from a list posting 
and you can't remember where it's from (which message), just go to the search 
box at fer3.com/arc, drop in a phrase from it, and click Search. You'll 
almost always find it. Then you can post the link to the original message. 
Messages before the summer of 2006 have arbitrary message numbers which were 
not part of the original messages so you should post a full URL if you want 
to link to one of those posts.




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