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Re: Unexpected USNO height correction precepts
From: Andrés Ruiz
Date: 2018 Sep 18, 16:58 +0200
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From: Andrés Ruiz
Date: 2018 Sep 18, 16:58 +0200
Hello dear Antoine,
Interesting disquisitions!
With a marine sextant, in sights for altitude or lunar distance, I have always treated Venus as a bright spot.
It is true that sometimes you can see its phase with a 7x50 binoculars, or a good sextant telescope. But I never worry about that.
So for me: Beating around the bush!
18/03/1977
00:02:17 UT1
Bap = -27.583333 º = -27º 35.0'
Lap = 144.895000 º = 144º 53.7'
NAUTICAL ALMANAC
Venus
GHA = 156.142468 º = 156º 8.5'
Dec = 16.316548 º = 16º 19.0'
SD = 0.4181 '
HP = 0.4406 '
ALTITUDE CORRECTION
Limb: center
Ref: SeaHorizon
Hs = 18.0617 º = 18º 3.7'
ic = 0.0000 '
heas = 4.5720 m
T = 10.0 ºC
P = 1010.0 hPa
Hoi = 18.0617 º
dip = 0.0627 º
Ha = 17.9989 º = 17º 59.9'
R = 0.0499 º
OB = -0.00000816 º
HP = 0.0073 º
PA = 0.00697593 º
Without SD correction:
Ho = 17.9561 º = 17º 57.4'
Marcq St. Hilaire LoP
LHA = 301.037468 º = 301º 2.2'
Hc = 17.9689 º = 17º 58.1'
Zn = 59.8 º
p = Ho-Hc = -0.012863 º = -0.771794 '
With SD correction:
Ho = 17.9561 º = 17º 57.8'
Best regards and fair winds!
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