Re: Navigation: celestial and otherwise
From: Robert Batchelor
Date: 2014 Jun 25, 12:27 -0700
Thanks for this map Frank! I've been looking at the log over the past few days. It looks like there are dead reckoning, chronometer and lunar readings for longitude. At least I'm assuming "ac" means dead reckoning. I'm being thick--you have any idea what "ac" is an abbreviation for?
According to Paul, there are evidently two sextants, some type of compass and a pelorus on board as well as a lead line, a chip log and some kind of patent or taffrail log. On my leg (Provincetown to Boston) I'm hoping to film some aspects of measurment for dead reckoning (speed and course), chronometer measurement (trying to figure out what to stage for this, probably something modern montaged with film of the Morgan chronometer I took in Mystic), and then lunar. There are some problems with all three. The captain evidently has not allowed for any of the lines off the back yet because it is too cramped back there. And then the sextant/lunar seems problematic as well (as you suggest in your earlier post). Most likely I'm going to have to montage between voyage footage and staged footage to make it work, possibly with animation in there and no doubt a great deal of voice over.
If anyone wants to share footage from other legs, I'd love it--interactive documentary is what the kids call it. My piece is going to be educational and focus on the longitude problem, and the way the log book illustrates using three types of data to gain certainty. From a mathematical and conceptual (geometrical I suppose) perspective, the problems get harder through each stage (dead r. easiest b/c linear, chronometer harder b/c must understand the globe, lunar hardest). This mirrors the log book in terms of which method was most commonly used. So the final product will be a bit of a three act play.