|
|
|
|
|||||
|
||||||
From: Frank Reed (no email)
Date: Sat Jun 24 2006 - 18:06:07 EDT
My personal thanks to everyone who attended the Navigation Weekend in
Mystic. The presentations were very successful, I thought. And the free-wheeling
discussions, whether during Q&A sessions or over dinner, were extremely
productive. I was pleased... :-)
We started out on Friday with a tour of Mystic Seaport's Collections
Research Center, led by Bill Peterson, Mystic Seaport's Senior Curator. Nearly a
secret, the CRC is the "museum within the museum". It is housed in an old mill
building that, from the outside, literally looks like an abandoned building.
Inside, it's keycard access, climate control, and sliding doors. Clearly an
enormous investment. We saw just a hint of Mystic Seaport's collection of
nautical instruments including three reflecting circles, drawers full of old
telescopes, strange star-identification devices. In addition we saw hundreds of
ship-builders half-models, row upon row of highly-detailed ship models in glass
cases, drawers filled with priceless scrimshaw, ten foot long sperm whale
jawbones and more. None of this is on public display. Bill led us out of the
climate-controlled section, down a humid corridor, and then opened a door to
part of Mystic Seaport's small craft collection --a grand hall filled with
hundreds of historic boats of all shapes and sizes. Opening that door always
reminds me of the closing scene in the movie "Raiders of the Lost Ark", a scene
where the camera pulls back to display a hangar filled with hundreds of crates
containing untold mysteries as far as the eye can see...
After the Collections Research Center, we stopped by the G.W.Blunt-White
Library to have a peek at two old logbooks, the log of the bark Reaper from
1809, and the log of the schooner Weymouth (listed as the log of the "Indramayoe"
on the Seaport's web site). Both of these logbooks contain worked lunar
distance observations, and I wanted everyone to have a chance to see the "real
thing" --original early 19th century lunar distance observations written out
long-hand-- with their own eyes. Next, was my presentation on the basic history
of lunar distance observations including a comparison of those logbook
calculations with an ordinary time sight to demonstrate that the amount of
mathematical work involved, while a little tedious, was by no means overwhelming.
Hebert Prinz's presentation on Lacaille's contributions to early nautical
astronomy, later on Friday, was fascinating, and the graphics that he assembled
to ilustrate it were professional in quality. It was interesting to see how
much interest was created by a graphical solution to the basic problem of
spherical trigonometry. We ran out of time for the last part of Herbert's
presentation, and we may have to get him to do it again in 2007. Friday evening,
half of us had an informal dinner at a nice seafood restaurant with a view of
Fisher's Island Sound in Noank. It was fascinating to hear how different
people had become interested in the topics of navigation and navigational history.
One of our attendees was the author of a history of the Blunt family, the
publishers of early editions of Bowditch's Navigator. Another was formerly an
engineer at Harvard Observatory. Others were interested in anything
navigational.
Saturday morning we were prepared to shoot some lunar distances at
Stonington Point starting at 9am. Alas, the Moon was visible only until about 8:45,
and then clouds moved in. Instead we shot some horizontal angles, some Sun
altitudes, and generally had a good time "messing around with sextants". The day
was predicted to be sparkling clear, but by mid-day we had light showers.
Typically unreliable Connecticut weather!
Saturday afternoon, Ian Jackson delivered a really excellent presentation on
Scoresby's whaling voyages and the associated navigational problems (and
George and Renee were present in spirit when he showed the traverse board
illustration). Ian's a talented speaker. Our next scheduled speaker, Trudy E. Bell
had to attend another conference (in New Orleans, related to the history of
floods). Fortunately, one of our other speakers, Craig Waff, was kind enough
to present her interesting paper on the "American Method" of telegraphic
longitude determinations. It's interesting how the history of electric longitude
determination is linked so closely with the development of efficient recording
devices.
Also Saturday, I presented the second part of my discussion of lunar
distance observations, focusing on some of the calculational and technical details
and trying to bust the myth that Bowditch's inventions with respect to lunars
were revolutionary. Immediately after, Don Treworgy did a nice planetarium
program demonstrating some of the tools that are available even in a
45-year-old planetarium for teaching celestial navigation. In particular he took us to
polar latitudes to see how low the Sun would fall on the North meridian
"below the pole" to demonstrate the circumstances of finding latitude by midnight
Sun which Ian Jackson had discussed earlier in the day.
Saturday night, our group buffet dinner turned out very nicely. Ken Gebhart
was our dinner speaker, and his tales of his navigational experience ferrying
planes across the Pacific and starting and growing Celestaire were both
interesting from a business standpoint and genuinely delightful as human
interest. It's great to hear little details about air navigation, like recording
"dome error" by writing it at various points on the inside of the canopy with a
marker. Myself, I was surprised to learn how much Ken's business had grown
just within the past ten years. Ken, by the way, won the longitude prize for the
Celestial Weekend, having traversed the most meridians to reach Mystic. Ken
ended his talk with several challenges for the future of celestial navigation
and celestial navigation education. In particular, can we encourage and
foster a Boy Scout badge for celestial navigation?
Sunday morning, we had another opportunity to shoot lunars at Stonington
Point. The Moon was barely visible through high cirrus and low-level haze. We
had more fun keeping track of the Moon visually as it moved in and out of
clouds than actually taking sights. With such poor conditions, it's not suprising
that our lunars were not very good. Almost everyone who managed even one
lunar recorded a distance that was too long by anywhere between 1.5 and 3.0
minutes of arc. Since the limb of the Moon was so indistinct in the haze, this
makes some sense.
Sunday afternoon, Craig Waff read his own paper on the early debates over an
American prime meridian. He focused on the people behind a "remonstrance", a
sort of petition signed by important men in marine business of that era,
including J. Ingersoll Bowditch. Craig also had many fascinating stories to tell
(over dinner) about the papers of Adams and the discovery of Neptune, which
is his current area of research. Craig Waff, by the way, is presently the
historian for the US Air Force's 89th Air Lift Wing, which makes him the
official historian for "Air Force One".
Luis Soltero, mathematician, software developer, and a highly experienced
sailor, delivered an hour-long presentation on the development of his StarPilot
navigation software. His philosophy for this product makes a lot of sense.
It runs on off-the-shelf calculators (the excellent TI-89 is the current
platform) and provides the navigator with the perfect celestial backup. He assumes
that very few navigators will practice enough to be proficient with paper
tables (or even have them onboard) when an emergency demands them, so he has
designed the StarPilot software to be intuitive, easy-to-use, and completely
independent of other sources of navigational information. There is also a PC
version which is essentially an emulation of the calculator version. Luis has
created an excellent sight planning tool for selecting twilight stars in
advance. He also includes a simple tool for working lunars, but this is more of a
"just for fun" tool without sufficient accuracy. The StarPilot software
includes a long-term almanac, but I should say that I am skeptical of its accuracy
outside the twenty year period from 1990 to 2010. That, of course, does not
diminish its practical utility at all, and it's a great piece of work. It was
fascinating to learn about it from the developer himself.
Or sextant workshop was an opportunity to look at some interesting old
instruments from Don Treworgy's personal collection, including an interesting
double-frame sextant and also a very early Tamaya with an almost absurdly large
telescope attached. We also experimented with a laser level, and I
demonstrated how to check for telescope collimation (although it took a while to find an
instrument which was not properly collimated!). Finally for the folks who
survived to the end, we had our door-prize drawing: two framed pages of lunar
distances from the Nautical Almanac of 1787. And one more seafood dinner down
in Noank by the marina with thanks and handshakes all around finished it off.
Phew... What a busy week for me. Maybe we'll do it again next year!
A final note:
Turn-out for the whole event was at the low end of expectations. The total
number of people who attended was only 20 with no more than 18 present at
once. This may simply mean that we need to find another sponsoring venue. The
management of Mystic Seaport apparently did nothing at all to publicize the
Celestial Weekend except to note it in their members' newsletter.
-FER
42.0N 87.7W, or 41.4N 72.1W.
www.HistoricalAtlas.com/lunars
|