NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Greg Rudzinski
Date: 2010 Jun 21, 20:20 -0700
The linked image #8373 shows the morning Sun's upper limb 20°23.8' (3267 pixels) above the horizon which is 300 yards away. Height of eye is 6 feet. Using the 1975 edition Bowditch formula for table 22 a dip correction of 22.7' minutes of arc is derived to be subtracted from Hs. The Ho for an upper limb Sun is then 19° 42.7'.
Hs 20°23.8'
U.L.corr. -18.4'
Dip Short corr. -22.7'
UT 14:32:52
Date 6/20/2010
GPS Lat 34°10.4'N
GPS Lon 119°13.8'W
Hc 19°41.0'
Ho19°42.7'
INT 1.4' Toward
Az 74.5°True
Dip Short Formula (Bowditch)
.4156 d + .5658 h/d = Dip in moa (to be subtracted)
d = distance in nautical miles
h = height of eye in feet
(.4156)(.15) + (.5658)(6/.15) = 22.7' moa
This method of taking a sight is not as good as a sea horizon but will allow photographers to try out camera CN if they are near a lake or body of water which is 200 or more yards across.
Greg Rudzinski
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