Partial Lunar Eclipse on
2021 Nov. 19
During the
deep partial lunar eclipse on November 19, 2021 the lunar screen will
probe the southern half of
Earth`s shadow. The middle and
high umbral angles of contacts during
immersions will
be followed by smaller ones
at emersions. Since 1996, the author has used
in his predictions and analyses a model described in Ref_1. that accurately
accounts for the figure of Earth as well as the off-axis projection
of the umbra. Since 2015, the model proposed
in Ref_2 has also
been used. Both models were
found to yield identical predictions which have been
compared to observed timings
gathered during several decades.
However, since
the atmospheric enlargement of Earth`s shadow
varies from one eclipse to another, simply using its all-time mean to derive the umbral radius may lead to errors of many
seconds in contact predictions, even when the shape
of the umbra
is adequately represented. Therefore, the atmospheric enlargement of the umbra
must be previously
determined, either from crater timings performed in preceeding eclipses or from a semi-empirical
correlation. For five years now, the author
has employed both methods in order to determine the umbral radius to be used
in his predictions and analyses. In addition, predictions have been systematically
compared with observed contact timings, yielding mean discrepancies
in the order of 4±3 sec. Based on an original correlation (to be published), he
estimates that the enlargement of the Moon`s
parallax π (or Earth´s figure) by the atmosphere during this eclipse will be 1.23±0.03%. That value is significantly
lower than the one currently
recommended by two other sources, as described in Ref_3. A few hundreds of
crater timings would allow the atmospheric
enlargement of the umbra to be
determined with sufficient accuracy for each eclipse.
Thus, the
long-term purpose of this work is to improve the predictability
of contact times and the brightness
of lunar eclipses based on observation of such phenomena.
That approach may contrast somewhat to others in the sense
that the information needed to improve future predictions has been painstakingly
gathered from systematic anlyses of several thousand
visual observations of past eclipses made by groups of
experienced amateur astronomers during three decades, which have also
contributed to data mentioned
in Ref_4. In other words, predictions
have been compared to observations whenever they are available in order to expand the understanding
on the phenomena,
thus leading to improved
semi-empirical correlations
for the Moon`s brightness and the atmospheric enlargement of the umbra.
Moderate volcanic
darkening should be expected for this eclipse. If
no more stratospheric eruptions
occur in the next couple of
months, the Moon is expected to exhibit an additional
1.2±0.4 mag drop at mid-eclipse due to ashes launched
during the explosions of Soufrière
St Vincent (April 09) and San Cristóbal
(March 19) volcanoes (Δm=0.9), that will add to lingering
effects from Sinabung and Sheveluch
(Δm=0.3). Thus the Moon, expected
to shine at -3.5 mag at mid-eclipse
if illuminated
by a clean stratosphere, is expected by the author
to dim to m=-2.3±0.5.
Magnitude estimates and
contact timings would be much welcome.
Please send us your observation
report and contribute to Lunar Eclipse Science!
Have clear
skies everyone!
Contact times calculated by Helio C. Vital
for the Partial Lunar Eclipse on 2021
Nov. 19
|
Atmospheric Umbral Enlargement Used for Moon`s
Parallax = 1.23% |
Δt=+69.3sec
IERS |
||||
|
CRATER |
UTC |
ANGLE |
CRATER |
UTC |
ANGLE |
|
IMMERSIONS |
EMERSIONS |
||||
|
PARTIALITY |
07:18:38 |
-46.57 |
Riccioli |
09:32:30 |
-26.01 |
|
Harpalus |
07:25:56 |
-40.14 |
Grimaldi |
09:32:34 |
-27.18 |
|
Aristarchus |
07:26:00 |
-50.45 |
Billy |
09:34:37 |
-30.96 |
|
Riccioli |
07:31:52 |
-64.10 |
Tycho |
09:37:20 |
-45.73 |
|
Grimaldi |
07:34:21 |
-65.27 |
Campanus |
09:38:10 |
-37.68 |
|
Kepler |
07:34:40 |
-57.09 |
Kepler |
09:49:39 |
-19.03 |
|
Plato |
07:35:39 |
-39.43 |
Aristarchus |
09:52:08 |
-12.42 |
|
Pico |
07:36:28 |
-41.00 |
Birt |
09:52:10 |
-33.06 |
|
Pytheas |
07:37:06 |
-50.61 |
Nicolai |
09:56:38 |
-42.32 |
|
Timocharis |
07:38:36 |
-47.72 |
Copernicus |
09:59:45 |
-17.32 |
|
Copernicus |
07:41:31 |
-55.37 |
Pytheas |
10:03:15 |
-12.57 |
|
Billy |
07:44:39 |
-69.07 |
Harpalus |
10:05:32 |
-02.15 |
|
Aristoteles |
07:44:59 |
-38.90 |
Timocharis |
10:09:06 |
-09.70 |
|
Eudoxus |
07:46:18 |
-40.50 |
Bullialdus |
10:11:21 |
-30.00 |
|
Manilius |
07:53:44 |
-51.55 |
Pico |
10:15:22 |
-03.02 |
|
Posidonius |
07:56:08 |
-43.87 |
Plato |
10:16:10 |
-01.45 |
|
Menelaus |
07:56:21 |
-50.42 |
Stevinus |
10:17:02 |
-35.00 |
|
Plinius |
08:00:26 |
-50.40 |
Manilius |
10:18:28 |
-13.52 |
|
Dionysius |
08:03:21 |
-56.37 |
Dionysius |
10:19:49 |
-18.32 |
|
Campanus |
08:04:13 |
-75.80 |
Menelaus |
10:22:51 |
-12.39 |
|
Birt |
08:06:50 |
-71.17 |
Eudoxus |
10:25:44 |
-02.52 |
|
Proclus |
08:09:49 |
-49.11 |
Aristoteles |
10:26:01 |
-00.93 |
|
Censorinus |
08:12:12 |
-57.05 |
Plinius |
10:26:55 |
-12.38 |
|
Mare Crisium |
08:13:19 |
-48.36 |
Censorinus |
10:27:19 |
-19.00 |
|
Taruntius |
08:14:49 |
-53.64 |
Goclenius |
10:29:04 |
-23.15 |
|
Bullialdus |
08:18:57 |
-68.10 |
Posidonius |
10:31:39 |
-05.88 |
|
Goclenius |
08:22:06 |
-61.22 |
Langrenus |
10:35:38 |
-22.03 |
|
Tycho |
08:24:27 |
-83.87 |
Taruntius |
10:35:49 |
-15.61 |
|
Langrenus |
08:26:37 |
-60.08 |
Proclus |
10:38:02 |
-11.09 |
|
Nicolai |
08:34:39 |
-80.46 |
Mare Crisium |
10:42:28 |
-10.35 |
|
Stevinus |
08:36:37 |
-73.11 |
PARTIALITY |
10:47:24 |
-08.65 |