NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Greg Rudzinski
Date: 2012 Mar 19, 08:30 -0700
Paul,
Titanic wreck position 41* 44' N 49* 57' W
UT time of collision 02:40:00 4/15/1912
Speed by RPM 21 kts.
Selecting stars only requires an approximate position so 42* N 50* W is a good starting point to DR East for 5.2 hours at 21 kts to a position of 42* N 47* 30' W at UT 22:30:00 4/14/1912 (early twilight with Sun -8* below horizon). Pub 249 can be used to select stars even though precession and nutation have changed Hc and azimuth values some over the last hundred years. For the exact Hc and azimuth values enter USNO web sight with assumed position and UT time for a full body list of stars and planets.
According to testimony the Titanic's navigators made no less than 30 CN observations per day. This means that azimuth and intercepts must have been used along with the occasional ex-meridian and time sight. The best candidate for an ex-meridian would be the star Alphard. Time sighting would have been tough to do within the time limits of twilight.
Greg Rudzinski
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