Interpolation in Pub.229

[pabrides]

Joe, I think I didn't express myself clear enough. In my previous posts by a typo I put Lat, where it should be Long. Yes, you are right, for the assumed Lat. one needs to take the whole number. Any Publications requires the whole number for Lat. But, when you calculate LHA, which is in my case  LHA=GHA+Long., ( long.. is E and I need to get LHA as a whole number. So, when I tried to use 4 deg Long. instead of 5 deg. I got LOP so far away from two other Sun shots, one can't reach it with a  six feet pole. And, also, you're right, that I kinda afraid of big intercepts. When I got an intercept close to almost one degree-I think I did wrong.

Well, practice makes us sane. ;>

Thank you

LOL... Now I am very interested in your work... I also live in E long and add AP to GHA.  Please send me two or three of your observations and let me try to work them... :)  please include the body, gmt time, gmt date, DR, HS, IE, dip, and  any other data you think I need.

thanks
joe

Joe, thank you for your interest.

The data corresponds to the hypothetical situation 12/18/1993..I just "polish" my basic knowledge, that's it ;>

Sun GMT 13-45-23   Hs 19-16.2
Sun GMT 13-47-02   Hs 19-07.8
Sun GMT 13-48-43   Hs 18-54.7

TC 120. V=6.5kn, DR @ 12-00 GMT 40-30N, 5-05E, IC=-1.0, Height of eye=10'.

One of the Sun sight appears ( in my cals of LOP) far away from the other two. But as soon as I used the interpolated data for Hc between 40 deg. Lat and 41 deg. Lat ( Z almost the same) I got much better result.

Moon sights  were very consistent:
Moon , UL 13-50-21  Hs 34-58.5
Moon        13-51-58   35-09.2
Moon       13-53-37   35-23.3


I got a fix.  But it is different from what it supposed to be. Not too much, but considering small distance traveled-appreciable ;>  And because. calcs were quite routine I wonder where did I screw up.

Well, I worked the first two sun shots and the first moon shot the long way; this is what I got:

Ships position at 13:50:21 GMT -  40:12.2N, 04:57.5E

This puts the DR 19 nm off; the true position is to the south-west.
I could clean this up a bit if I decrease the scale, but for fun this is close enough.  I thought I captured the numbering of meridians  in the photo but I missed...  The compass rose is centered at 40N, 06E.

Notice sun 1 and sun 2 LOPs are on top of each other - thats due to the close observations and the ship having the same true course as the LOP line.  The Moon 1 LOP then almost dissects the  sun 1 intercept.

Joe, thank you. My results were 40-10, 05-31.  Supposed to be 40-23, 05-17. But we are in the same hemisphere. Meaning, we are fine ;>

Well... I had to go back... i screwed the pooch with declination.  Your 1993 almanac kind of threw me..  Here in this next plot I reduced the last sun shot and the first moon shot...  I should not be too far off.  cross your fingers

joe