NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Occultation puzzle
From: Peter Hakel
Date: 2011 May 21, 00:07 -0700
From: Peter Hakel
Date: 2011 May 21, 00:07 -0700
The Wikipedia entry for Aldebaran contains the following image:
http://en.wikipedia.org/wiki/File:Occultation.jpg
Based on the information on this page and after some trial and error with Excel (see attached) I came up with the following plausible coordinates in time and space at which this image may have been created:
New Orleans area: 30N 90W
UT: July 29, 1997, 10h 08m 30s
This really should be only a point along an entire LOP of possible solutions, which I did not investigate further. I neglected refraction which I'd think would have a small effect for such a tiny lunar distance (center-to-center topocentric LD = Moon SD = 15.5') and the overall achievable accuracy in this exercise (no obviously visible refractional flattening of Moon's disk). Parallax is important (center-to-center geocentric LD = 34.4')
Accompanying data look consistent with everything else:
The Moon age (25 days, "waning crescent") and phase (23% or about 1/4 illuminated)
Local time (UT-6h) => around 4am, about an hour before sunrise ("predawn")
The two bodies would have appeared due east at an altitude of roughly 34 degrees.
Peter Hakel
http://en.wikipedia.org/wiki/File:Occultation.jpg
Based on the information on this page and after some trial and error with Excel (see attached) I came up with the following plausible coordinates in time and space at which this image may have been created:
New Orleans area: 30N 90W
UT: July 29, 1997, 10h 08m 30s
This really should be only a point along an entire LOP of possible solutions, which I did not investigate further. I neglected refraction which I'd think would have a small effect for such a tiny lunar distance (center-to-center topocentric LD = Moon SD = 15.5') and the overall achievable accuracy in this exercise (no obviously visible refractional flattening of Moon's disk). Parallax is important (center-to-center geocentric LD = 34.4')
Accompanying data look consistent with everything else:
The Moon age (25 days, "waning crescent") and phase (23% or about 1/4 illuminated)
Local time (UT-6h) => around 4am, about an hour before sunrise ("predawn")
The two bodies would have appeared due east at an altitude of roughly 34 degrees.
Peter Hakel
File:
File:
File:
File:
