Hi gents. Here's the answer to this confusing situation. It's much simpler than you can imagine. Pub. No. 249 Vol. 2 page. xi does a pretty BAD job of showing how to get LHA and the Ap longitude used for plotting. But, at least they have examples in Eastern longitudes!
I'll use the example in the attached sheet at the bottom of this post. It's from Pub. No. 249
First, we'll get LHA the easy way.
In Eastern longitudes get LHA as follows;
Body- Moon
DR. Longitude- E 7° 28'
GHA- 323° 37'
Make it easy on yourself. IGNORE the minutes of GHA and minutes of DR. longitude.
Add only the whole degrees of GHA and DR. longitude
323° + 7° = 330°
Then add 1° to the sum above; 330° + 1° = 331°
So, in this case- LHA= 331°
Try the other examples on that sheet and your answers for LHA will agree with theirs.
Second, we'll get the Ap longitude which is needed when plotting. Please understand that Ap longitude means, "Assumed position longitude".
In Eastern longitudes get Ap longitude as follows (using the same GHA as above).
Use only the minutes of the GHA and the whole degree of the DR. longitude
Moon's GHA- 323° 37'
DR. Longitude- E 7° 28'
Always subtract the GHA minutes from 60
60' - 37' = 23'
Next....combine the DR. longitude whole degree with the 23 minutes found just above to get the Ap longitude.
Ap longitude= E 7° 23' (I left off the 2 leading zeros)
Yes, you can perform all of the steps to get LHA and Ap longitude as they show you in '249, if you can possibly understand the awful way they format it and explain it, but I presented it this way so you wouldn't get confused.
Frankly, I have NO IDEA why they make this process so wretchedly difficult for us mortals to understand?!
The following is supposed to be funny-
If you can't figure out how to get the LHA and Ap longitude in Eastern Longitudes the solution is easy- don't sail there!
I'll use the example in the attached sheet at the bottom of this post. It's from Pub. No. 249
First, we'll get LHA the easy way.
In Eastern longitudes get LHA as follows;
Body- Moon
DR. Longitude- E 7° 28'
GHA- 323° 37'
Make it easy on yourself. IGNORE the minutes of GHA and minutes of DR. longitude.
Add only the whole degrees of GHA and DR. longitude
323° + 7° = 330°
Then add 1° to the sum above; 330° + 1° = 331°
So, in this case- LHA= 331°
Try the other examples on that sheet and your answers for LHA will agree with theirs.
Second, we'll get the Ap longitude which is needed when plotting. Please understand that Ap longitude means, "Assumed position longitude".
In Eastern longitudes get Ap longitude as follows (using the same GHA as above).
Use only the minutes of the GHA and the whole degree of the DR. longitude
Moon's GHA- 323° 37'
DR. Longitude- E 7° 28'
Always subtract the GHA minutes from 60
60' - 37' = 23'
Next....combine the DR. longitude whole degree with the 23 minutes found just above to get the Ap longitude.
Ap longitude= E 7° 23' (I left off the 2 leading zeros)
Yes, you can perform all of the steps to get LHA and Ap longitude as they show you in '249, if you can possibly understand the awful way they format it and explain it, but I presented it this way so you wouldn't get confused.
Frankly, I have NO IDEA why they make this process so wretchedly difficult for us mortals to understand?!
The following is supposed to be funny-
If you can't figure out how to get the LHA and Ap longitude in Eastern Longitudes the solution is easy- don't sail there!