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(meteorobs) Re: Yorktown meteors
Dave,
I have a program provided by a friend. I compared both programs to the
current date and time an both gave identical results. I went back to
1/1/88 (the furthest back I could verify) and again both gave identical
results. Obviously one of the programs is faulty beyond a certain number
of years.
As for the main question I would agree with you that the difference is
due entirely to precession.
Clear Skies! It's raining here :(
Bob
Dave Hostetter wrote:
>
> >
> > Actually a solar longitude of 208.0 back in 1781 would have occurred at
> > 23:22 UT on October 16. This would have been on the evening of October
> > 16, 1781 in eastern USA.
> >
> > Bob Lunsford
>
> Hi, Bob:
>
> That's interesting. The Astronomy Calculator at
> http://www.halcyon.com/gml/astro/ (which generally seems to work pretty
> well) gives a peak almost exactly 24 hours later than you got -- 23:13:31 UT
> on October 17, 1781. I wonder what the discrepancy is.
>
> But the question remains -- is the change in the date of the Orionids' peak
> (from around the 17th in 1781 to around the 21st now) due simply to
> precession as Robert Gardner suggested, or due to precession plus other
> factors? For instance, are there changes in the meteoroids' orbital paths
> over the centuries that would cause the proper solar longitude for the peak
> to be something other than today's value of 208 degrees? I suspect that
> precession is the complete answer, but I'm not sure.
>
> Dave
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