Sky & Telescope - January 2024 - 50

JANUARY 2024 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
The Quads Are Back
THE ANNUAL QUADRANTID meteor
shower will share the sky with the lastquarter
Moon when the display reaches
its maximum during the early-morning
hours of January 4th. While this will
lower the potential number of meteors
visible, the extra light won't ruin the
event. It helps that the Moon is in Virgo
more than 60° from the shower radiant
in northern Boötes, the location of the
defunct constellation Quadrans Muralis
for which the shower is named.
Minima of Algol
Dec.
UT
3
6
9
12
15
15:11
12:00
8:49
5:38
2:27
17 23:17
20
23
26
29
20:06
16:55
13:44
10:33
Jan.
1
4
7
9
12
15
18
21
24
27
29
The Quads have multiple parent
bodies, with asteroid 2003 EH1, Comet
96P/Machholz, and possibly other
comets all contributing to the shower's
dusty flux. The debris stream is narrow,
so we zip through it quickly - the reason
the shower's peak lasts only about
six hours. This year that occurs around
9 UT (4 a.m. EST) - a favorable time
for the eastern half of North America,
where the radiant will be high in the
northeastern sky.
Action at Jupiter
Arcturus
AS JANUARY OPENS, Jupiter is nicely
positioned for early-evening viewing.
On the 1st it transits the meridian at
about 7:30 p.m. local time. But make
haste. By month's end it hits that mark
almost two hours earlier and in bright
twilight - a sure sign the current
apparition is winding down. During
the course of the month, Jupiter's disk
shrinks perceptibly from 44.0″ down
to 39.8″ as the planet dims very slightly
from magnitude -2.6 to -2.4.
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 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.
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. (Eastern
Standard Time is UT minus 5 hours.)
December 1: 7:27, 17:22; 2: 3:18,
UT
29
7:23
4:12
1:01
21:50
18:40
15:29
12:18
9:08
5:57
2:46
23:36
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 2024 * SKY & TELESCOPE
Perseus is conveniently positioned at the
zenith during evening hours in January. Every
2.87 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
TRIANGULUM
34
13:13, 23:09; 3: 9:05, 19:00; 4: 4:56,
14:52; 5: 0:47, 10:43, 20:39; 6: 6:34,
16:30; 7: 2:26, 12:21, 22:17; 8: 8:13,
18:08; 9: 4:04, 14:00, 23:55; 10: 9:51,
19:47; 11: 5:42, 15:38; 12: 1:34, 11:29,
21:25; 13: 7:21, 17:16; 14: 3:12, 13:08,
23:03; 15: 8:59, 18:55; 16: 4:50, 14:46;
17: 0:42, 10:37, 20:33; 18: 6:29, 16:24;
19: 2:20, 12:16, 22:12; 20: 8:07, 18:03;
21: 3:59, 13:54, 23:50; 22: 9:46, 19:41;
23: 5:37, 15:33; 24: 1:29, 11:24, 21:20;
25: 7:16, 17:11; 26: 3:07, 13:03, 22:58;
27: 8:54, 18:50; 28: 4:46, 14:41; 29:
0:37, 10:33, 20:28; 30: 6:24, 16:20; 31:
2:16, 12:11, 22:07
January 1: 8:05, 18:00; 2: 3:56,
13:52, 23:47; 3: 9:43, 19:39; 4: 5:35,
15:30; 5: 1:26, 11:22, 21:18; 6: 7:13,
17:09; 7: 3:05, 13:01, 22:56; 8: 8:52,
18:48; 9: 4:44, 14:39; 10: 0:35, 10:31,
20:27; 11: 6:22, 16:18; 12: 2:14, 12:10,
http://www.skyandtelescope.org/algol
Sky & Telescope - January 2024

Table of Contents for the Digital Edition of Sky & Telescope - January 2024
