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    Re: About Lunars, part 4
    From: George Huxtable
    Date: 2002 Mar 19, 21:56 +0000

    Chuck Griffiths asked-
    
    >First, I have a set of observations from last night that I'm hoping you might
    >have a look at George, and see if it looks like I'm still headed in the right
    >direction. From approximately 27-42.0 N, 82-44.2 W I took a set of observation
    >as follows:
    >
    >(All times GMT 19 March followed by altitudes Degree-Minutes)
    >
    >Venus 00:11:41 7-50.6
    >Moon 00:12:48 44-52.6
    >Venus 00:14:02 7-25
    >Moon 00:14:02 45-25.6
    >
    >Lunar Distances
    >00:14:59 37-43.4
    >00:15:27 37-43.2
    >00:16:01 37-43.0
    >
    >Venus 00:16:36 6-43
    >Moon 00:17:31 43-51.6
    >Venus 00:18:09 6-24
    >Moon 00:19:09 43-30
    >
    >I roughly averaged the sights and used the following for my calculations:
    >
    >Venus 7-5.6
    >Moon 44-12.5
    >Distance between 37-43.2
    >
    >>From which I calculated:
    >
    >B .69733
    >P 38.43635
    >R 6.65151
    >d 37.97333
    >D 38.72479
    >
    >SD 15.1995
    >HP 55.1
    >
    >D1 (00:00:00) 38.58036
    >D2 (01:00:00) 39.03829
    >
    >T 00:18:55 v. real time of observation of 00:15:29
    >
    >So, based on the fact that the Moon was rather high and, by my
    >observations, was
    >moving at an apparent speed of about 24 arc minutes an hour can I assume that
    >some of my error is due to "parallactic retardation"? Or, did I make some more
    >basic mistake?
    >
    >One other question from Part 4, how do Bruce's tables compare to the
    >tables that
    >used to be in Bowditch?
    >
    >Chuck
    
    ================
    
    Reply from George-
    
    It's good to know that Chuck for one is taking my lunar stuff seriously. I
    wonder if there's anyone else still following it?
    
    I will try to get a bit of time to check over the numbers Chuck has quoted,
    and I hope others will try it too, as a useful exercise to practice with.
    Another listmember may beat me to it. Something is lacking as yet though:
    we need Chuck's height of eye in order to calculate dip. What value did
    Chuck use for his own calculations?
    
    I presume Chuck's positions for Moon and Venus have come from the 2002
    Nauticul Almanac. Not all of us will have that: I am one that doesn't
    (yet). We would instead calculate positions of Moon and Venus by computer
    or pocket calculator, or take it from a website. To put us all on an equal
    basis, perhaps Chuck might provide the values he used for GHA and
    declination of the Moon and Venus, on 2002 March 19 at 00:00:00 and
    01:00:00 GMT. Also the value for Moon HP and for Venus parallax  (page
    259?) from the almanac or wherever he has obtained them from.
    
    As for the ex-Bowditch tables, I'm not in a position to make the comparison
    with Bruce Stark's tables that Chuck asks for. I have some Bowditch tables
    that Dan Allen kindly copied for us on his website, but it seems not to be
    complete enough to use for that purpose. Perhaps I didn't pick up all the
    pages. Has anyone succeeded in calculating lunars from that information?
    
    George Huxtable.
    
    ------------------------------
    
    george---.u-net.com
    George Huxtable, 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
    Tel. 01865 820222 or (int.) +44 1865 820222.
    ------------------------------
    
    
    

       
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