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» Online Classroom   »   » Public Discussion of Cel Nav   » Ex. 5.4 Sun Sight #2

   
Author Topic: Ex. 5.4 Sun Sight #2
Rich A


 - posted July 22, 2016 11:25 AM      Profile for Rich A           Edit/Delete Post 
I have a question about Ex. 5.4 Sun Sight #2 – according to the answer sheet (pg. 223), the d-value (for Section 2) is -0.5. Looking in the NA for 26 Jul 1978, the d-value at the bottom of the page is +0.5. In Box 3, this gives you a dec of N19 21.9, instead of N19 22.7.

In the end, the difference of the bearing T/A from Zn comes out to .8’. It’s not a lot – but I want to know if I am messed up in some way. Can you help? Thanks.

From: Lacey
Capt Steve Miller


 - posted July 22, 2016 11:57 AM      Profile for Capt Steve Miller           Edit/Delete Post 
First, when determining the sign for the 'd' for the declination correction you must look at the Declination minutes of the day/hour in the problem then check the NEXT hour to see if the minutes value has gotten bigger or smaller. If bigger then the sign is (+), if smaller then the sign is (-). In this problem the minutes are smaller thus the 'd' is -0.5'.
Second the N19° 21.9' is correct -- N19° 22.3' - 0.4 ('d' correction for the 0.5 value) = N19° 21.9'.

From: Starpath
Rich A


 - posted July 22, 2016 01:18 PM      Profile for Rich A           Edit/Delete Post 
Got it - that makes sense. Thanks.
From: Lacey


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