NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Antoine Couëtte
Date: 2013 Apr 25, 10:17 -0700
RE : http://fer3.com/arc/m2.aspx?i=123663
Hello Greg, and
Hello Peter (further down)
This post concerns the first of the (now) 4 problems built up and submitted by Greg.
Regarding the 02 JUN 2013 SUN shot at UT=01:59:40, Greg, you wrote :
QUOTE
To remedy this I have looked at my original notes which shows a UT 1:59:40 for 2 June 2013. Reworking using USNO shows quite a few changes which are shown highlighted on the attachment. There was a change in GHA, assumed longitude, Hc, Hs, Ho, and intercept. This should fix things I hope.
UNQUOTE
I have no longer any problem now with your updated value. :-)
*******
Regarding the POLARIS shot at 05:00:31 UT, Greg, you wrote :
QUOTE
Regarding Polaris. The Pub 249 reduction uses a Q value and a precession nutation correction that are rounded to the nearest minute of arc. I would not expect a close match to USNO or other programs.
UNQUOTE
This seems to fully explain our 0.4' difference then. Good News !
*******
About POLARIS... and this concerns Peter Hakel this time (are you here Peter ??)
In
" : http://fer3.com/arc/m2.aspx/Group-Project-USCG-student-sample-problems-Couëtte-apr-2013-g23602 "
and from Auxiliary Position 24°N / 143°40' , observing Polaris at UT 05:00:31 at Sextant Height 23°04'1 (corrected for only Instrument Error), I got a Geocentric Height Ho = 22°52'0 (I concur with Greg's published value) and an intercept of -36.4' (Away) in Azimuth 359°5, hence an Observed Latitude of N 23°23'6 at time of observation UT 05:00:31 (or a shifted latitude of N 23°23'7 at UT 05:00:00).
RE
": http://fer3.com/arc/m2.aspx/Group-Project-USCG-student-sample-problems-Couëtte-apr-2013-g23607 " to which I did not read a reply to.
Peter, while all our other intercepts fully match to +/- 0.1 ' , I still can not reconcile this Latitude I found of 23°23'6 (or 23°23'7) with your value of 23°25'5 published in
" http://fer3.com/arc/m2.aspx/Group-Project-USCG-student-sample-problems-PeterHakel-apr-2013-g23606 ".
Any cue from your part, Peter ?
Best Regards to all,
Kermit
----------------------------------------------------------------
NavList message boards and member settings: www.fer3.com/NavList
Members may optionally receive posts by email.
To cancel email delivery, send a message to NoMail[at]fer3.com
----------------------------------------------------------------