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I have been a lurker on this list since the late Tony Severdia introduced me
to it around 1994.  Unfortunately my job often takes me out of town and out of
touch for three to four weeks at a time, so I am usually well behind in my
e-mail.  I check it whenever I can, but I usually just look at items directed
specifically to me and thjose with subjects of particular interest to me.  On
the rare occasion where I have something to contribute, someone has already said
what I intended to say, and much more eloquently than I ever could.

Nevertheless, I read all the postings on this list, albeit months after they
are written.  (I am currently working on the beginning of April of this year.)
 I have never understood all the activity regarding lunar distances.  After
reading a typical posting I ask myself why I wasted my time reading it, and
wonder why people subject themselves to something that is apparently so difficult
and time-consuming.

Well, I finally get it, thanks to Frank Reed's Lunars Workshop, which I
attended at Mystic Seaport in Connecticut on Friday.  There were about 20 lunatics,
er, lunarians in attendance, four or five of which were members of this list.
 It was a pleasure to meet such active members as Frank and Dan Allen (who
had driven from Utah!) and a few other lurkers like me.  (BTW, if you have any
questions about cameras, digital or film, Dan's the man!)

The workshop took about four hours on Friday, with a session of sight taking
on Saturday.  During the first three Frank explained some of the history of
lunar distances and how they worked.  In the optional last hour he got into some
of the mathematics involved.  Yes, before the publication of the Almanac in
1767, it may have taken four hours to clear a lunar, but once the lunar
ephemeris was published it would only take about 20 minutes.  But it was still a
long, multi-step process, requiring the taking of several sights, to determine
longitude from a lunar.  Thanks to Frank, though, you don't have to do all the
steps in order to test your skill at measuring a lunar distance.

Happily, my commitment on Saturday took less time than expected, and I was
able to get to the sight-taking session at Stonington Point.  I got there about
a half hour early, but found Dan and another lunarian, Gus, already were
"playing" with their sextants.  They had not started measuring lunar distances
because the low-contrast moon was not yet spotted against the hazy sky near the
horizon.  Once we did find it we began measuring the angle between the near
limbs of the sun and the moon.  I had looked up what the lunar distance should
have been, so we were able to preset our sextants, making the job much easier.  I
was using a Davis plastic sextant, and Dan and Gus were using "real"
sextants, but we all seemed to be getting reasonable numbers.

Then Frank showed up, and so did Don Treworgy, the Planetarium Director at
Mystic Seaport, with a carload of sextants from the Seaport's collection for us
to use.  I quickly put away my Davis and picked up an Astra IIIB (figuring
that if I broke it, it would be less of a loss than some of the expensive/antique
sextants Don brought).  I believe there were eight of us there, including
Frank and Don.  Then the fun part began.

Frank used the browser on his cell phone to connect to his web site
(www.historicalatlas.com/lunars), which has a program which allows you to quickly check
the quality of your lunar distance measurement, knowing your actual longitude
and local time (two things that you would not know in "real life").  My first
sight was 0.1' off, which is considered good.  I should have quit while I was
ahead, because my second, which I told Frank did not feel right, was 0.8'
off, which is bad.  My third, which felt much better, was 0.2' off, which is
fair.  At that point I felt I could start kidding around with the other guys,
whose results ranged from excellent (there was one "perfect" measurement) to
terrible (as Frank put it, somewhere in Manhattan).  Poor Dan could not get a
decent measurement with his Astra IIIB, but the fault was apparently with the
sextant and not with Dan, since no one, including Frank, could get a decent
measurement with Dan's sextant.  We spent some time trying to adjust it, with little
improvement.  As we left it, we still did not know what the problem was.

One of the beauties of Frank's program is that you don't need a sea horizon
or artificial horizon to test your skill.  I have every intention of trying
this from my house.

We all were able to see a large sunspot through our sextant telescopes. Don
had been tracking it for a while and said it was very active.

We attracted the requisite number of curious bystanders.  After explaining
what we were doing, some walked away satisfied with our explanation, but others
left thinking we were nuts.  I guess there is some truth in that.

Some of us had to leave, but the ones that stayed had another treat in store.
 One of the guys had his PDA with him, and was able to compute the position
of Venus.  Those who had not yet put away their sextants were able to preset
the altitude and sweep the horizon at the approximate azimuth to do a daylight
observation of Venus.  Don was the first to spot it, but it kept on ducking
behind a few clouds that were up there.

I certainly learned a lot in these two days, and enjoyed myself in the
process.  Frank, thanks for putting this workshop together for us.  We all
appreciate your efforts and your contributions to the list.

Stan

P.S.  I did a quick lunar as I was leaving the marina for home this evening.
I used the Davis plastic sextant, which was adjusted for zero index error
yesterday, but was sitting in the hot car all day today.  I did not check it
again for taking the sight.  This is my excuse for being 16.3' off.  Bah!

   

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