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 » Online Classroom   »   » Public Discussion of Cel Nav   » Question 5.7.4

Author Topic: Question 5.7.4
 Bg posted June 30, 2010 02:54 AM                   I am currently a bit stumped. On question 5.7.4 I have followed the normal procedure from box 1 to 4 but I don't end up with the same LHA as the answer in the back of the book. After checking a few times I am not sure where I am going wrong . I take 27th March 1981 and the GMT of 13:07:00 and get GHA 13deg 39.4. I then go to the minutes column of 7min, go down to 00 seconds and get a GHA m.s of 145deg 00'. I add them to get a total of 158 39.4. I then get an a-lon of 15deg 39.4 subtract it because it is West and end up with LHA 143deg and in the back of the book they show 0deg. Could someone please tell me where I am going wrong so that I don't make the mistake again.
 HHEW posted June 30, 2010 04:42 AM                   The sun's GHA increases 15° per hour, so in 7 minutes it cannot have changed 145°. In 8 minutes the increase is 2° so what you're looking for is something less than 2°.Looking at the Increments and Corrections table, I see 1°45' as the increase for 7 minutes 00 seconds - i.e., 1° 45', not 145°00'.-Hewitt Schlereth
 Bg posted July 01, 2010 08:16 AM                   Thank you, your info on the GHA of the sun helped me see things from a different perspective
 Bg posted July 01, 2010 08:16 AM                   Thank you, your info on the GHA of the sun helped me see things from a different perspective

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