Sky & Telescope - January 2023 - 50

JANUARY 2023 OBSERVING
Celestial Calendar
Polaris
Mizar
URSA
MINOR Little
Dipper
DRACO
Quadrantid Meteor Shower
1 am, Jan 4
URSA
MAJOR
10°
Quadrantid
radiant
BOÖTES
HERC ULES
Looking Northeast
Exercise Your Quads
THANKS TO SERIOUS competition
from a 12-day-old Moon, this is an offyear
for the annual Quadrantid meteor
shower. The waxing gibbous won't set
until the start of morning twilight,
essentially shutting the window on
dark skies. Peak activity is predicted to
occur on January 4th at around 4 UT
(11 p.m. EST January 3rd).
Under ideal, moonless conditions,
maximum rates can exceed 100 meteors
per hour, making the Quads one
Minima of Algol
Dec.
UT
1
4
7
10
13
15
18
21
24
27
30
14:41
11:30
8:19
5:08
1:57
22:46
19:35
16:25
13:14
10:03
6:52
Jan.
2
5
7
10
13
16
19
22
25
27
30
of the best displays of the year. The
shower appears to radiate from northern
Boötes, once home to the obsolete
constellation Quadrans Muralis and
memorialized in the shower's name.
Given that the Quadrantids produce
a substantial number of fireballs, you
might want to check for an hour or
so before dawn on the morning of the
4th. Look halfway up the northeastern
sky - and be sure to keep a cup of your
favorite hot beverage close at hand.
Action at Jupiter
Arcturus
AS TWILIGHT FADES on the evening of
January 1st, Jupiter will be a prominent
sight high in the south. The -2.4-magnitude
planet crosses the meridian
roughly half an hour after sunset. By
month's end, it will do so more than
1½ hours before sunset, signifying that
the current apparition is starting to
wind down. On January 1st, Jupiter
sets around 11:30 p.m. local time, and
before 10 p.m. on the 31st.
Any telescope reveals the four big
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 on any given date and time.
All the observable interactions between
Jupiter and its satellites and their shadows
are tabulated on the facing page.
Features on Jupiter appear closer to
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
Standard Time is UT minus 5 hours.)
December 1: 9:30, 19:26; 2: 5:22,
UT
3:42
0:31
21:20
18:09
14:59
11:48
8:37
5:27
2:16
23:05
19:55
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.
50 JANUARY 2023 * SKY & TELESCOPE
pPerseus is conveniently positioned at
the zenith during evening hours in January.
Every 2.7 days, Algol (Beta Persei) dips
from its usual magnitude 2.1 to 3.4 and
back. Use this chart to estimate its brightness
in respect to comparison stars of
magnitude 2.1 (Gamma Andromedae) and
3.4 (Alpha Trianguli).
18
30
PERSEUS
38
Algol
21
29
TRIANGULUM
34
15:18; 3: 1:13, 11:09, 21:05; 4: 7:01,
16:56; 5: 2:52, 12:48, 22:43; 6: 8:39,
18:35; 7: 4:31, 14:27; 8: 0:23, 10:18,
20:14; 9: 6:10, 16:05; 10: 2:01, 11:57,
21:53; 11: 7:49, 17:44; 12: 3:40, 13:36,
23:32; 13: 9:27, 19:23; 14: 5:19, 15:15;
15: 1:11, 11:06, 21:02; 16: 6:58, 16:54;
17: 2:50, 12:45, 22:41; 18: 8:37, 18:33;
19: 4:28, 14:24; 20: 0:20, 10:16, 20:11;
21: 6:07, 16:03; 22: 1:59, 11:55, 21:50;
23: 7:46, 17:42; 24: 3:38, 13:34, 23:29;
25: 9:25, 19:21; 26: 5:17, 15:13; 27:
1:09, 11:04, 21:00; 28: 6:56, 16:52;
29: 2:48, 12:43, 22:39; 30: 8:35, 18:31;
31: 4:27, 14:22
January 1: 0:20, 10:16, 20:11; 2:
6:07, 16:03; 3: 1:59, 11:55, 21:50; 4:
7:46, 17:42; 5: 3:38, 13:34, 23:29; 6:
9:25, 19:21; 7: 5:17, 15:13; 8: 1:09,
11:05, 21:00; 9: 6:56, 16:52; 10: 2:48,
12:44, 22:39; 11: 8:35, 18:31; 12: 4:27,
14:23; 13: 0:19, 10:14, 20:10; 14: 6:06,
http://www.skyandtelescope.org/algol
Sky & Telescope - January 2023

Table of Contents for the Digital Edition of Sky & Telescope - January 2023
