NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Nautical almanac first point of aries
From: John Doe
Date: 2012 Mar 12, 11:17 -0700
From: John Doe
Date: 2012 Mar 12, 11:17 -0700
Greetings, I have been looking at the online nautical almanac at http://www.tecepe.com.br/scripts/AlmanacPagesISAPI.isa/pages?date=03/12/2012 and for today monday 12 mar 2012 the GHA angle for aries is 80 deg 47.1 min at 18:00 h GMT I think I can convert the GHA for aries to time and that should be the same as sidereal time at Greenwich. ( (80./15) + (47.1/60)/15 ) = 5.38566... taking the 5 out and mult the fractional part by 60 .3856666 * 60 = 23.1399... and taking out the 23 and doing the same .13999 * 60 = 8.3 I used this web site to get sidereal time at longitude 0 deg 0 min http://tycho.usno.navy.mil/cgi-bin/sidereal-post.sh and pressed compute at approx. 16:00:00 GMT 05:23:45.4 The seconds are not in close enough agreement which makes me think I am missing something or have made an error in the computations?
