There will be a total penumbral lunar eclipse on Jan. 31. The moon willAccording to the xephem program, the eclipse occurs at 16:08:17 UT. The geocentric latitude of the moon at that time is -0:59:16 degrees (very close to -1 degree).
pass entirely through the lighter part of the Earth's shadow without any of
it being in the umbra or darkest portion. I don't know the exact time of
the event. This is a somewhat rare event. I thought that this would be an
excellent opportunity for you dialists to check the functioning of your
sundials (moondials) and to test some of the theories that we discussed last
week. (ie. Does the use of the EOT improve accuracy.)The reason that this eclipse is particularly good for sundial readings is
that the moon will be brighter during totality than a normal eclipse and
should cast a more distinct shadow. Of course the sun/earth/moon alignment
will be better than during a partial eclipse also.Does anybody know the times for this eclipse?
John Carmichael
Attached is a gif file showing the position of the moon and the umbra and penumbra at the time of the full moon. This picture was produced by the xephem program.
It may be interesting to investigate correction by the EOT as well as correction by EOT for six months from now--the moon will be near the place the sun will occupy in six months, and I'm having a hard time deciding which EOT correction should be used (I know, I should be able to decide this...).
Finally, also according to xephem, the moon will have zero geocentric latitude (i.e. it will be at the node) on Feb 1 at 11:19:12 UT. You might see whether the moondial is even more accurate at this time.
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