Sky & Telescope - October 2022 - 50

OCTOBER 2022 OBSERVING
Celestial Calendar
Occultation
ends at
moonrise
Action at Jupiter
Occultation
begins at
moonrise
Occultation
ends at
moonset
Occultation
begins at
moonset
JUPITER IS FRESH FROM its September
26th opposition date and nicely placed
for telescope observers. Indeed, for
those who prefer viewing the planet in
the evening hours, the post-opposition
months are an apparition's prime time.
On the first of the month, Jupiter is
already nearly 20° above the eastsoutheastern
horizon at the end of
astronomical twilight and reaches the
meridian at roughly 12:30 a.m. local
daylight-saving time. The feature-rich
planet presents a disk nearly 50″ across
and gleams brightly at magnitude -2.9.
Even by month's end, it's only 0.1 magnitude
fainter.
Any telescope reveals the four big
pThis map shows the visibility of the Mercury occultation. Along most of the path the event occurs
in daylight, while observers in the dark-shaded region experience a twilight occultation.
be sure to watch for a two-step winkout,
or better, record it on video with
your telescope. You'll find more details
at https://is.gd/etaleonis.
Finally, the Moon's third cover-up is
something of a rarity but is also challenging
to observe. On the morning of
October 24th, observers across much of
North America may see the exceedingly
thin (0.8% illuminated) Moon cover
Mercury's tiny (5.1″) disk. From most
places, the event occurs after sunrise.
The good news is that the planet
shines at magnitude −1.1, making it visible
by daylight in a scope. The bad news
is that the Moon will appear as thin as
an onion skin and may not be visible at
all unless your skies are exceptionally
clear. It might look as if Mercury simply
vanishes into the blue!
A section of western Canada and the
area of southern California-western
Nevada will be the only places where
the planet will be occulted during
morning twilight. At these locations, it
might be possible to view the occultation
with just a pair of binoculars. The
rest of us will need a scope fitted with a
safe solar filter and adhere to a careful
procedure to view the event. Use a
planetarium program to get the coordi50
OCTOBER 2022 * SKY & TELESCOPE
nates of the Sun and Mercury for that
morning. With the solar filter in place
on your scope, center the Sun, focus,
and then shift the telescope in right
ascension and declination to Mercury's
position. You can then remove the filter
and enjoy the show.
Minima of Algol
Sept.
UT
2
5
8
11
14
17
20
22
25
28
21:09
17:58
14:46
11:35
8:23
5:12
2:01
22:49
19:38
16:27
Oct.
2
5
8
11
13
16
19
22
25
28
31
Galilean moons, and binoculars usually
show at least two or three. The moons
orbit Jupiter at different rates, changing
positions along an almost straight line
from our point of view on Earth. Use the
diagram on the facing page to identify
them by their relative positions on any
given date and time. All the observable
interactions between Jupiter and its satellites
and their shadows are tabulated
on the facing page. Find events timed
for when Jupiter is at its highest.
Features on Jupiter appear closer to
UT
9:34
6:23
3:12
0:00
20:49
17:38
14:27
11:16
8:04
4:53
1:42
These geocentric predictions are from the recent
heliocentric elements Min. = JD 2457360.307
+ 2.867351E, where E is any integer. They were
derived by Roger W. Sinnott from 15 photoelectric
series in the AAVSO database acquired
during 2015-2020 by Wolfgang Vollmann, Gerard
Samolyk, and Ivan Sergey. For a comparison-star
chart and more info, see skyandtelescope.org/algol.
the central meridian than to the limb
for 50 minutes before and after transiting.
Here are the times, in Universal
Time, when the Great Red Spot should
cross Jupiter's central meridian. The
dates, also in UT, are in bold. (Eastern
Daylight Time is UT minus 4 hours.)
September 1: 9:18, 19:14; 2: 5:09,
15:05; 3: 1:00, 10:56, 20:52; 4: 6:47,
16:43; 5: 2:38, 12:34, 22:29; 6: 8:25,
18:21; 7: 4:16, 14:12; 8: 0:07, 10:03,
19:59; 9: 5:54, 15:50; 10: 1:45, 11:41,
21:36; 11: 7:32, 17:28; 12: 3:23, 13:19,
23:14; 13: 9:10, 19:06; 14: 5:01, 14:57;
15: 0:52, 10:48, 20:43; 16: 6:39, 16:35;
17: 2:30, 12:26, 22:21; 18: 8:17, 18:13;
19: 4:08, 14:04, 23:59; 20: 9:55, 19:50;
21: 5:46, 15:42; 22: 1:37, 11:33, 21:28;
23: 7:24, 17:19; 24: 3:15, 13:11, 23:06;
25: 9:02, 18:57; 26: 4:53, 14:49; 27:
0:44, 10:40, 20:35; 28: 6:31, 16:27; 29:
2:22, 12:18, 22:13; 30: 8:09, 18:04
October 1: 4:03, 13:59, 23:55; 2:
GREGG DINDERMAN / S&T
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https://www.is.gd/etaleonis http://www.skyandtelescope.org/algol
Sky & Telescope - October 2022

Table of Contents for the Digital Edition of Sky & Telescope - October 2022
