NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Greg Rudzinski
Date: 2011 Jan 16, 11:49 -0800
Jeremy,
Good going on capturing the rare Venus ex-meridian dip short backsight.
Dip short from 106 feet seems to be very sensitive to horizon distance estimation.
-60.4' at 1.0 NM
-48.5' at 1.25 NM
Dropping the height of eye down would help a lot here.
For this exercise a LOP is determined by a smartphone Palm CN program:
Azimuth 190.1�
Intercept 6.5' away
This gives me something to compare the ex-meridian to.
As Requested (Venus 8m 27s after M.P.)
1. (a) = 1.9635(Cos7�16.3')(Cos18�30.0')/Sin(11�13.7') = 9.48
2. Ex.corr. = 9.48(8.45)(8.45)/60 = 11.3'
3. Dip short correction is -48.5' for a 1.25NM horizon from an H.E. of 106ft. *
4. Latitude 7� 10.1' S (6.2 NM away)
* an online calculator was used for the dip short calculation
http://www.starpathdemos.com/bowditch/table14.htm
Greg Rudzinski
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