# Azimuth of the sun calculations...HELP!

Help!

Iām trying to work through azimuth of the sun calculations. Iāve forgotten how to re-calculate the latitude (L), Dec, and LHA, listed as ā1. 2. 3.ā at the bottom of the format for Azimuth calculations.

Can anyone help me figure out how this is done? Iām studying for my 1600 ton master exam.

Thanks,

Curt

Latitude. Round it to the nearest whole number.
Find your t angle = GHA
+m & s
W-/E+ +/- longitude

This will give you your LHA. If it is more that 180 the subtract 360 and your t angle is east. If this number is less than 180 the LHA is t angle and it is W. If you subtract upside down the t-angle is east. ALways make sure to go to the nearest Observed Longitude to make LHA a whole number.

Sto1 Lat
Sto2 Dec
Sto 3 t-angle

Subtract if lat and declination are contrary add if Lat and dec or the same
rcl1 cos x rcl2 cos x rcl3 cos +/- rcl 1 sin x rcl 2 sin = 2nd sin = HC

Sto1 LAt
sto2 DEC (make this negative if lat and dec are contrary)
sto3 HC

rcl2sin -(rcl1 sin x rcl3 sin) = divide rcl1cos divide rcl3 cos = 2nd cos = Z

If take lat north or south and t angle east or west

NE Z=ZN
SE 180-Z=ZN
SW 180+z = ZN
NW 360 - Z = ZN

[quote=curtgetz;25935]Help!

Iām trying to work through azimuth of the sun calculations. Iāve forgotten how to re-calculate the latitude (L), Dec, and LHA, listed as ā1. 2. 3.ā at the bottom of the format for Azimuth calculations.

Can anyone help me figure out how this is done? Iām studying for my 1600 ton master exam.

Thanks,

Curt[/quote]
Curt, I just got home but in the morning I will respond to your message with a format and trig calculations as was probably taught to you at L.E. Fletcher if the one Capt. Lee doesnāt work for you. His is good and I have used it but is not formatted the way you probably are used to doing itā¦Steve.

capt leeās method is a good one to use, more importantly it is the method used and explained in the books & tables you can reference during your upcoming examination. for this reason alone I personally recommend using this system: if you get in a jam during during the exam itās nice to know youāve got that! in fact, I have always made a point of training myself from HO229 etc then when in the exam double checking my work.

[B]1. Lat to one decimal place[/B]
[B]2. Declination to one decimal place, if contrary to Lat. enter as negative[/B]
[B]3. LHA to one decimal place if over 180 enter as negative[/B]

[B]Solution using 36X calculator: R 3sine divided by (R 1cosine times R 2tangent minus R 1sine times R 3cosine)=secondDD tangent=Z. If answer is negative add 180=Z [/B]
[B]R means recall [/B]
[B]Z to Zn see Pub. 229 or 249[/B]
[B]Remember to use parenthesese after, R 3sine divided by, or solution will be wrong. Iām about to go to Biloxi to gamble but if you need more helpā¦text me at 251-581-1899ā¦Steve[/B]

[quote=Capt. Lee;25941]Latitude. Round it to the nearest whole number.
Find your t angle = GHA
+m & s
W-/E+ +/- longitude

This will give you your LHA. If it is more that 180 the subtract 360 and your t angle is east. If this number is less than 180 the LHA is t angle and it is W. If you subtract upside down the t-angle is east. ALways make sure to go to the nearest Observed Longitude to make LHA a whole number.

Sto1 Lat
Sto2 Dec
Sto 3 t-angle

Subtract if lat and declination are contrary add if Lat and dec or the same
rcl1 cos x rcl2 cos x rcl3 cos +/- rcl 1 sin x rcl 2 sin = 2nd sin = HC

Sto1 LAt
sto2 DEC (make this negative if lat and dec are contrary)
sto3 HC

rcl2sin -(rcl1 sin x rcl3 sin) = divide rcl1cos divide rcl3 cos = 2nd cos = Z

If take lat north or south and t angle east or west

NE Z=ZN
SE 180-Z=ZN
SW 180+z = ZN
NW 360 - Z = ZN[/quote]

The easiest way I can remember if ātā is E or W is that if it is a morning shot ātā is east and an evening shot ātā is west (the sun rises in the east and sets in the west)

Man, I really am old school, (did my first one when I was 19yo). I just bust out a pencil and do it on scratch paper, per the example in the front of the 229.

I can do it like that too. That is actually how I learned to do it and then I took a celestial class at Delgado and these two old Sealand Captains made me use the calculator. I told them I already knew how to do it my way, but they convinced me and I am glad I listened.

I took the Chief Mate/Master 1 Week Celestial at Star Center in Dania and all those guys there use 229. It is easier and faster for me to use the calculator/keystroke method to sight reduction. After using this method a million times I will never forget this formula.

I learned using HO 214. The captains and mates I sailed with on deliveries refused to use 229. The pocket calculator hadnāt been invented at that time.

One old retired United Fruit Co captain told me anything other than 210 or 214 was a shortcut and āreal navigatorsā wouldnāt take shortcuts. I later caught him using Coogleās 2 Minute Azimuths.