NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Simple celestial navigation in 1897
From: Frank Reed CT
Date: 2006 Feb 25, 21:36 EST
From: Frank Reed CT
Date: 2006 Feb 25, 21:36 EST
The online digital collection of the G.W. Blunt-White Library at Mystic Seaport has been expanded quite a bit recently. There's a "navigation workbook" from a Pacific whaling voyage of the Charles W. Morgan in 1896-97. Note that Joshua Slocum, also from New Bedford, was sailing the Pacific in his little sloop Spray at this time, too (the Morgan was in the North Pacific, eventually hunting whales off Hokkaido so they were never all that close to each other). The navigational technique displayed in this workbook is very simple. The latitude is calculated by subtracting the Sun's observed noon altitude from 89d 48' and then adding or subtracting the Sun's declination (the 90 degrees minus 12' value is an old approximate combined correction for dip, refraction, and semi-diameter). For the time sights, this navigator uses the same 12' combined correction. And that's it -- day after day, latitude by noon Sun and longitude by time sight. The CWM was already 56 years old on this voyage, and whaling was a minor business in the 1890s, so maybe it's not surprising that there's no "rocket science" in this navigation. Nonetheless, this very simple celestial was good enough to cross the Pacific from California to Micronesia and then on to Japan. Here's the index to the digital collection: http://www.mysticseaport.org/library/initiative/MsList.cfm -FER 42.0N 87.7W, or 41.4N 72.1W. www.HistoricalAtlas.com/lunars
