Total Lunar Eclipse of December 21, 2010
Observation
Report and Comments
Helio de Carvalho Vital
Location: Rio
de Janeiro (22o55`24” S;
43o13`
Instruments:
Atmospheric conditions: Good transparency and
excellent stability; clear skies; morning twilight in progress after 07:00 UT.
Local altitude of the Moon: from 17o (U1) to 5o (last photo) with moonset predicted for 8:07
UT.
First naked-eye perception of the penumbral shading of the northeastern
limb of the Moon`s disc occurred at 6:03 UT when the magnitude of the penumbral eclipse was 0.58.
Limb and
Mid-Crater Contact Timings
|
Immersions |
UT |
|
Partial Phase (U1) |
06:33:08 |
|
Grimaldi |
06:38:05 |
|
Campanus |
06:47:04 |
|
Kepler |
06:52:06 |
|
Aristarchus |
06:56:38 |
|
Copernicus |
07:00:14 |
|
Pytheas |
07:04:58 |
|
Timocharis |
07:10:37 |
|
Dionysius |
07:15:56 |
|
Manilius |
07:16:33 |
|
Menelaus |
07:19:20 |
|
Goclenius |
07:23:08 |
|
Langrenus |
07:27:11 |
|
Eudoxus |
07:28:32 |
|
Proclus |
07:31:20 |
Estimate of the Eclipse Brightness
Poor contrast due the
combination of the very low altitude of the Moon and the influence of the
morning twilight prevented magnitude estimates to be made. However, based on
the visibility of the limb and of features in the umbra, the Danjon Number was estimated as L=2.4
(±0.4). According to the correlation we have determined between L and
the Moon`s magnitude (m), that would correspond to an
approximate mid-totality value of m≈ -1.6. Such figures, if confirmed,
would indicate a moderately bright eclipse, as bright as it could be
considering the position of the Moon inside the umbra, thus not significantly
obscured by volcanic aerosols in the stratosphere as expected.
Photos
The advance of the umbral shadow during immersion was captured by the author
in picture 1. Overexposures revealed more and
more orange-colored regions inside the progressing umbra during the first
partial phase of the eclipse as totality approached and the Moon was about to
hide behind a faraway hill just a few minutes before moonset (picture 2).
