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Re: Real accuracy of the method of lunar distances
From: Bill Noyce
Date: 2004 Jan 6, 11:15 -0500
From: Bill Noyce
Date: 2004 Jan 6, 11:15 -0500
I've been following the discussion of statistical tests with interest (and not a lot of
understanding), but one statement of Jan Kalivoda's stood out:
> For lunars, PE of 20" times 4.5 gives 90" = approximately 180 seconds of time = approximately
> 45 minutes of longitude (the exact value depends on the actual velocity of the Moon in R.A.).
In fact, the actual value depends on the velocity of the apparent moon and comparing
body in topocentric coordinates, not RA. As George Huxtable has pointed out, the rate of
change of an observed lunar distance can be surprisingly slow, due mostly to refraction and
parallax. My recollection is that it can be slow enough that a 90" difference in observed
distance could correspond to over 300 seconds of time -- is that right, George?
-- Bill
