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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@huxtable.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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