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From: Randall Morrow
Date: 2011 Dec 1, 11:35 -0800
I'm trying to do sight reductions by calculator but I'm having trouble with the sign(s). On example I have found is below but I have seen others in which the sign(s) do not change with same versus contrary latitude and declination. Is this correct? (I don't remember where I found this)
Thanks, Randy
sin Hc = (cos LHA x cos DR lat x cos dec) + or - (sin DR lat x sin dec)
Note: use + if lat and dec are same names.
cos Az * = sin dec +/- (sin Hc x sin DR lat) divided by (cos Hc x cos DR lat)
Note: use + when lat and dec are of opposite names.
* Remember Az is the azimuth angle. To get Zn (Azimuth) apply the rules:
Northern Lat: LHA > 180 deg. Azimuth = Azimuth Angle. LHA < 180 deg. Zn = 360 - Az
Southern Lat. LHA > 180 deg. Zn = 180 deg. - Az. LHA< 180 deg. Zn = 180 + Az
Randall F Morrow PT
Kern County - Bakersfield
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