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Re: Exercise: Lower Transit
From: Peter Hakel
Date: 2009 Sep 19, 15:56 -0700
The altitude of the Pole (i.e. latitude) is the sum of the Ho (15 deg 35.8') and Kochab's colatitude (polar distance = 90 - Dec = 15 deg 52.9').
Peter Hakel
From: "Anabasis75@aol.com" <Anabasis75@aol.com>
To: NavList@fer3.com
Sent: Saturday, September 19, 2009 3:08:53 PM
Subject: [NavList 9806] Exercise: Lower Transit
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From: Peter Hakel
Date: 2009 Sep 19, 15:56 -0700
Jeremy,
I did not know how to interpret the Temp/pressure correction, so I just used standard conditions. This is apparently another piece of terminology that I have yet to learn...
This way I obtain the following coordinates of your vessel at the moment of observation:
N 31 deg 28.7'
W 74 deg 11.8'
At that moment the GP of Kochab was:
GHA: 254 deg 11.8'
Dec: N 74 deg 07.1'
The (west) longitude is given by the GHA minus 180 for lower transits.
I did not know how to interpret the Temp/pressure correction, so I just used standard conditions. This is apparently another piece of terminology that I have yet to learn...
This way I obtain the following coordinates of your vessel at the moment of observation:
N 31 deg 28.7'
W 74 deg 11.8'
At that moment the GP of Kochab was:
GHA: 254 deg 11.8'
Dec: N 74 deg 07.1'
The (west) longitude is given by the GHA minus 180 for lower transits.
The altitude of the Pole (i.e. latitude) is the sum of the Ho (15 deg 35.8') and Kochab's colatitude (polar distance = 90 - Dec = 15 deg 52.9').
Peter Hakel
From: "Anabasis75@aol.com" <Anabasis75@aol.com>
To: NavList@fer3.com
Sent: Saturday, September 19, 2009 3:08:53 PM
Subject: [NavList 9806] Exercise: Lower Transit
A ship is sailing in the North Atlantic. on 15 September 2009.
At 04h 09m 44s local time a lower meridian transit of the star Kochab was
taken by moonlight. Hs is 15 deg 50.3'
At 04h 09m 44s local time a lower meridian transit of the star Kochab was
taken by moonlight. Hs is 15 deg 50.3'
Height of eye is 103 feet
Index correction is -1.2'
Temp/pressure correction is +.2
ZD is +4
The 1930 Star fix from the previous evening is
Index correction is -1.2'
Temp/pressure correction is +.2
ZD is +4
The 1930 Star fix from the previous evening is
Lat 30 deg 48.9' North
Long 073deg 22.2' West
Crs is 304 Spd 8.2 Knots
Long 073deg 22.2' West
Crs is 304 Spd 8.2 Knots
Determine a 0409 Latitude.
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