NavList:
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Re: Sight reduction formulae
From: Stan K
Date: 2011 Dec 1, 14:51 -0500
From: Stan K
Date: 2011 Dec 1, 14:51 -0500
Randall,
In my previous e-mail I should have added that
1) in the sin formula, that sign is always +
2) in the cos formula, that sign is always -, but the formula is missing parentheses
In my previous e-mail I should have added that
1) in the sin formula, that sign is always +
2) in the cos formula, that sign is always -, but the formula is missing parentheses
cos Az * = (sin dec +/-
(sin Hc x sin DR lat)) divided
by (cos Hc x cos DR lat)
Stan
Stan
-----Original Message-----
From: Randall.F.Morrow <Randall.F.Morrow@kp.org>
To: NavList <NavList@fer3.com>
Sent: Thu, Dec 1, 2011 2:37 pm
Subject: [NavList] Sight reduction formulae
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
Randall F Morrow PT
Kern County - Bakersfield
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From: Randall.F.Morrow <Randall.F.Morrow@kp.org>
To: NavList <NavList@fer3.com>
Sent: Thu, Dec 1, 2011 2:37 pm
Subject: [NavList] Sight reduction formulae
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
NOTICE TO RECIPIENT: If you are not the intended recipient of this e-mail, you are prohibited from sharing, copying, or otherwise using or disclosing its contents. If you have received this e-mail in error, please notify the sender immediately by reply e-mail and permanently delete this e-mail and any attachments without reading, forwarding or saving them. Thank you.