My first Magazine Sky & Telescope - 01.2019 | Page 52

JANUARY 2019 OBSERVING
Celestial Calendar
Action at Jupiter
Shadow Play
THE SUN, MOON, AND EARTH line
up in space to create two eclipse events
this month (as seen from Earth). The
first, on January 5–6, is a partial solar
eclipse, when the Moon passes between
Earth and Sun and appears to take a
deep “bite” out of our star. Wear proper
eye protection or use a solar projector
to view this event. Visibility is best for
East Asia, though the Sun is low at that
time of year. For Vladivostok the eclipse
begins at 9:38 a.m. local time, with the
Sun just 7° high at the moment the
Moon makes “fi rst contact” with it.
Eclipse maximum occurs at 10:57 a.m.
As the Moon says its fi nal farewell at
12:24 p.m., the Sun has risen only 23°
above the horizon.
Visibility in North America is limited
to parts of Alaska. In Adak, the event
begins on January 5th at 3:01 p.m.
HAST, reaches eclipse maximum at
4:25 p.m., and concludes at 5:42 p.m.
In Unalaska, fi rst contact occurs at
4:16 p.m. with the deepest point of the
eclipse reached at 5:33 p.m. The Sun
sets at 6:00 p.m., so the fi nal stage of
the eclipse is lost to view. (The eclipse
ends at 6:43 p.m. local time.)
This partial solar eclipse is followed
by a total lunar eclipse on January 21,
2019. Totality is visible throughout
50
JA N UA RY 2 019 • SK Y & TELESCOPE
p A total solar eclipse occurred on March 20,
2015. It was viewed through clouds as a partial
eclipse from Kavala, Greece.
North and South America, as well as
for some of Europe and Africa. Partial
stages are visible in large parts of the
world. Central, South, and Southeast
Asia, and Australia miss out on this
one. See page 18 for more details.
Minima of Algol
Dec. UT Jan. UT
3
5 2:53
23:42 3
6 15:53
12:42
8 20:31 9 9:32
11 17:20 12 6:21
14 14:09 15 3:10
17 10:58 17 23:59
20 7:47 20 20:49
23 4:36 23 17:38
26 1:26 26 14:27
28 22:15 29 11:17
31 19:04
These geocentric predictions are from the
recent heliocentric elements Min. = JD
2445641.554 + 2.867324E, where E is any
integer. For a comparison-star chart and
more info, see skyandtelescope.com/algol.
local standard time at the beginning
of January and reaches an altitude of
about 15° before it disappears in bright-
ening twilight. In practical terms, the
window of observability is only about
an hour long, and that’s assuming you
have an open horizon to the southeast.
Observing conditions improve with
each passing morning, however. By the
end of January, the observing window
is closer to two hours long, and Jupiter
stands around 22° high in the south-
east when it’s lost to sunlight.
Any telescope shows the four big
Galilean moons, and binoculars usu-
ally show at least two or three. Use the
diagram on the facing page to identify
them at any date and time.
The January interactions between
Jupiter and its satellites and their shad-
ows are tabulated on the facing page.
Find events timed for when Jupiter is at
its highest in the early morning hours.
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.)
Dec. 1, 2:26, 12:22, 22:18; 2, 8:13,
18:09; 3, 4:05, 14:01, 23:57; 4, 9:53,
19:48; 5, 5:44, 15:40; 6, 1:36, 11:32,
21:27; 7, 7:23, 17:19; 8, 3:15, 13:11,
23:07; 9, 9:02, 18:58; 10, 4:54, 14:50;
11, 0:46, 10:41, 20:37; 12, 6:33, 16:29;
13, 2:25, 12:21, 22:16; 14, 8:12, 18:08;
15, 4:04, 14:00, 23:55; 16, 9:51, 19:47;
17, 5:43, 15:39; 18, 1:34, 11:30, 21:26;
19, 7:22, 17:18; 20, 3:13, 13:09, 23:05;
21, 9:01, 18:57; 22, 4:53, 14:48; 23,
0:44, 10:40, 20:36; 24, 6:32, 16:27; 25,
2:23, 12:19, 22:15; 26, 8:11, 18:06; 27,
4:02, 13:58, 23:54; 28, 9:50, 19:45; 29,
5:41, 15:37; 30, 1:33, 11:29, 21:24; 31,
7:20, 17:16.
Jan. 1, 3:12, 13:07, 23:03; 2, 8:59,
18:55; 3, 4:51, 14:46; 4, 0:42, 10:38,
20:34; 5, 6:30, 16:25; 6, 2:21, 12:17,
22:13; 7, 8:09, 18:04; 8, 4:00, 13:56,
23:52; 9, 9:47, 19:43; 10, 5:39, 15:35;
11, 1:31, 11:26, 21:22; 12, 7:18, 17:14;
13, 3:09, 13:05, 23:01; 14, 8:57, 18:53;
15, 4:48, 14:44; 16, 0:40, 10:36, 20:31;
G E
JUPITER RISES JUST AFTER 5 a.m.