(11-25-2022, 02:30 PM)CelNav57 Wrote: I'm at a loss to understand how to calculate LHA while sailing in Eastern longitudes.
What I know;
LHA in Eastern longitudes= GHA + ApL (Assumed position longitude) (minus 360° if necessary)
Example;
Date- November 25, 2022
GMT- 10:10:59
ApL= E 025° 45'
GHA= 336° 00.7'
LHA= 336° 00.7' + 25° 45'= 361°45.7' - 360° = 1° 45.7'
But, here's the confusion, LHA in Eastern longitudes is supposed to be rounded up or something like that and I'm not really sure if it is supposed to be rounded up. Information on the web is vague and not explained well enough making too many assumptions. Another possibility is that very few who speak English are sailing, doing CN, in the Eastern hemisphere.
So, my estimate to solve the problem is simply this (tell me if I'm wrong)
Eastern longitudes, LHA= GHA (whole degree's) + ApL (whole degrees) + 1
The problem above could be easily solved like this- LHA= 336° + 25° + 1° (minus 360°) = 2°
Any ideas about this?
Greetings, CelNav57
I Think you are right. I would just make LHA a round number by making assumed lloongituda 26 deg. Therefore 336 +26 =362. 362-360=2 deg. I saw this method ina few books. When you take 25 deg instead of 26 , you make LHA smaller, because to round 25.45 to 25 is much more "rounding" than from 25.45 to 26.
Anyway, your assumption is correct the way I see it. Again, I saw the examples of calculating LHA in Lat.E and it is exactly how it was done. And, by the way, you may use LHA of 1 deg 45.7 for your calculations but then you need to go through correction tables which anyway will round up the final result.
This is the way I see it.
Thank you!
This little attachment shows much more clearer what I meant, that my previous post ;>