NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Altitudes for lunars. was Re: Lunars - Finding Bermuda in 1807
From: Frank Reed
Date: 2007 May 22, 11:08 -0400
From: Frank Reed
Date: 2007 May 22, 11:08 -0400
George, you wrote: " I have an Almanac for 1864, and by then the Almanac was giving (where available) the Sun, a planet or two, and 5 or 6 stars, some to East of the Moon, some to the West, for the navigator to choose between, or make multiple observations. I don't know from what date that greater choice was offered. Has anyone access to an Almanac from around 1807, to see how many lunar distances were tabulated then?" Checking 1818 and 1831, it's one star at a time. The change to multiple stars happened I believe in 1834, along with many other changes to the almanac (or possibly a year earlier since a few changes were rolled out before the big revision). In that same year, the lunar distances for the planets were added, and the column for "P.L. Diff" was included. Also, the distances were thereafter for times in GMT rather than GAT. So how do we square this chronology with Basil Hall's account of using multiple stars? I think he simply remembered wrong. Memoirs like his certainly count as primary source history; he was there, and those things did happen. But we always have to remember that the author is reconstructing some details. He had detailed journals of his voyages (which he refers to occasionally) that formed the basis of his books, but he was writing it all out for those books 20 or 30 years later. Similarly, in his account of the shipwreck of the Arniston in 1815, he notes that Royal Navy vessels carry four or five chronometers. This also may be anachronistic. That is, four or five chronometers on a Royal Navy vessel may have been common in 1835 when he was writing out the story for one of his books, but in 1815 I would bet not. -FER --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---