A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2020 Aug 4, 12:52 -0700
Here are some photos of a copy in poor condition of the "Nautical Almanac & Astronomical Ephemeris" from 1786. I've got a few of these from the late 18th century and a bunch from the 19th century. I use this one teaching celestial navigation, especially my class in "Lunars" which I'm running again next week (online: http://ReedNavigation.com/Lunars/). The NA&AE is the ancestor of both the modern "Nautical Almanac" and the modern "Astronomical Almanac".
Something to notice: the longitudes of the planets are specified in the extended sexagesimal system. See the headings "S.D.M.S."? The D.M.S. part is familiar, but the initial S might puzzle... It's sign, as in zodiac sign. The signs, which are now relegated to the world of astrology, were still employed by astronomers even at this late date in the Enlightenment. They were, after all, nothing more than 30° bands of ecliptic longitude --really just an extension of the usual angular measure system.
Oh and next time you try to poke a little fun at astrology, remember this (or it may come back to bite you): the signs have been precisely defined for many centuries, while the borders of the astronomers' constellations have only been defined since 1925!
Clockwork Mapping / ReedNavigation.com
Conanicut Island, USA ...where it's a windy day!!