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    Re: Interpolation to latitude
    From: Gary LaPook
    Date: 2009 Nov 9, 21:18 -0800

    LMT is not zone time, it is the time at the local meridian so already
    includes the adjustment you are taking about.
    
    gl
    
    On Nov 9, 7:22�am,  wrote:
    > L.Gray, "100 Problemsin Celestial Navigation" Problem 1-1
    >
    > "...sailiing from New York to Azores... May 13, 1993. �DR position at 0730 
    (GMT) will be 40 deg 10' N and 50 deg 15' W. �Planning for a round of 
    twilight sghts..."
    >
    > 50 deg 15 ' of long is equal to 3 hr. 21 m, which we add to LMT to get GMT.
    >
    > � � � � � � � � � � LMT � � �GMT
    > Nautical twilight �0337 � � �0658
    > Civil twilight � � 0414 � � �0735
    > Sunrise � � � � � �0446 � � �0807..."
    >
    > Appendix B (which is "how to")
    >
    > "1. On the right-hand daily page of the almanach, enter the upper half of 
    the table (a.m) with the expeced DR latitude at the time of the twilight. 
    (interpolate for latitude, either by eye or mathematically)...... Convert 
    each LMT to GMT �by adding... or subtracting .. the time equivalent of the 
    expected DR longitude-found on the first yellow page in the back of the 
    almanach"
    >
    > My question is: why there is no mentioning �of interpolaion for the 
    longitude in calculating twilight phenomenon? �As I mentioned before, I think 
    the interpolation for the zone meridian ( in this case 45 deg W) should be 
    included in calculation also. �I don't think it was included. �
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