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Re: Venus Moon Occultation Lunar Captured by DSLR
From: Peter Monta
Date: 2015 Dec 11, 21:40 -0800
From: Peter Monta
Date: 2015 Dec 11, 21:40 -0800
Hi Brad,
Is no one going to answer this?
I'll take a shot at it. You're certainly right that the (diurnal geocentric) parallax of any body is zero when it's at the zenith (on a spherical Earth), by definition. The nitpicky side issue in the case of Venus is that, even if the Moon is at zenith, Venus at occultation time would not quite be at zenith, so would show a very small horizontal parallax. The other nitpicky case is for an ellipsoidal Earth and an observer at midlatitudes, in which case the Moon at zenith is not in line with the geocenter and would still have a small parallax.
Cheers,
Peter
