My first Magazine Sky & Telescope - 03.2019 | Page 52

MARCH 2019 OBSERVING
Celestial Calendar
Action at Jupiter
JUPITER SHINES on in Ophiuchus in
Lunar Occultation
THERE ARE NO OCCULTATIONS
of 1st-magnitude stars by the Moon
visible from North America in 2019.
The brightest stars to be hidden by
the Moon (at least for our continent)
range only from magnitudes 2.9 to 3.9:
Delta 1 Tauri; Zeta Tauri; Delta, Eta, and
Mu Geminorum; Gamma Librae; and
Gamma Capricorni. The next 1st-mag-
nitude event involves Antares in 2023,
with visibility limited to Florida.
In the meantime, we enjoy the dim-
ming of lesser lights. On the night of
March 12–13, the Moon passes in front
of Delta 1 (δ) Tauri (HD 27697) in the
Hyades for western North America. The
waxing crescent will be heading toward
its set, standing only 20° or 25° high
when the dark leading limb slips across
the 3.8-magnitude star. Delta 1 disap-
pears at the Moon’s northeastern edge
near or after 6 h UT and reappears at
the west-northwestern edge less than
an hour later. The reappearance may
be diffi cult to detect as it occurs at the
Moon’s bright limb. The Moon is only
10° or 15° above the horizon at most at
that point, so atmospheric effects add
to the challenge.
About 25 or 30 minutes after Delta 1
goes missing, the Moon occults Delta 2
(HD 27819). The 4.8-magnitude star
disappears behind the Moon’s eastern,
dark limb. We won’t see the star again
this night, as the Moon sets before the
star reappears at its bright limb.
Observers near Seattle, Salt Lake
City, and other places along the
northern limits of the occultation path
should watch for a grazing event, when
Delta 1 seems to skim by the Moon’s
northern limb, very near the termina-
tor. Look for the star to blink on and
off as it’s covered and revealed by the
moving Moon’s valleys and mountains.
A few minutes after the graze event, the
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M A RCH 2 019 • SK Y & TELESCOPE
Moon’s leading edge covers Delta 2 .
Delta 1 is a known double, and
observations of the occultation are
highly desired by the International
Occultation Timing Association (IOTA).
Timetables are available from the IOTA
website ( https://is.gd/IOTApredict ). You
can also calculate predictions for your
observing site using IOTA’s free soft-
ware program, Occult ( https://is.gd/
IOTAoccult ).
Here are some times for a few major
cities. For Delta 1 : Sacramento, disap-
pearance 10:56 p.m., reappearance 11:45
p.m. PDT; Los Angeles, d. 10:58 p.m.,
r. 11:53 p.m. PDT; Seattle, graze 11:13
p.m. PDT; Denver, d. 12:11 MDT, gr.
12:20 MDT; Salt Lake City, gr. 12:18
a.m. MDT.
For Delta 2 : Seattle, d. 11:16 p.m.
PDT; Sacramento, d. 11:22 PDT; Los
Angeles, d. 11:27 p.m. PDT; Salt Lake
City, d. 12:23 a.m. MDT; d. Denver,
12:25 a.m. MDT.
Minima of Algol
Feb. UT Mar. UT
1
4 8:06
4:55 2
4 0:19
21:09
7 1:45 7 17:58
9 22:34 10 14:47
12 19:23 13 11:36
15 16:13 16 8:26
18 13:02 19 5:15
21 9:51 22 2:04
24 6:41 24 22:54
27 3:30 27 19:43
30 16:32
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.
March, rising about 2 a.m. local stan-
dard time as the month opens. By the
31st, its rise time has crept forward only
to about 1:30 a.m., thanks to daylight-
saving time.
Jupiter stands highest in the south
as the Sun rises. You may notice an
improvement in visibility as the planet
brightens from magnitude –2.0 to –2.2
over the course of the month. Jupiter
broadens in March as well, its equato-
rial diameter increasing from 36″ wide
to 40″ wide by the 31st.
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 March 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
Daylight Time is UT minus 4 hours.)
Feb. 1: 4:01, 13:57, 23:53; 2: 9:48,
19:44; 3: 5:40, 15:36; 4: 1:31, 11:27,
21:23; 5: 7:19, 17:14; 6: 3:10, 13:06,
23:02; 7: 8:57, 18:53; 8: 4:49, 14:45; 9:
0:40, 10:36, 20:32; 10: 6:28, 16:23; 11:
2:19, 12:15, 22:11; 12: 8:06, 18:02; 13:
3:58, 13:53, 23:49; 14: 9:45, 19:41; 15:
5:36, 15:32; 16: 1:28, 11:24, 21:19; 17:
7:15, 17:11; 18: 3:06, 13:02, 22:58; 19:
8:54, 18:49; 20: 4:45, 14:41; 21: 0:36,
10:32, 20:28; 22: 6:24, 16:19; 23: 2:15,
12:11, 22:06; 24: 8:02, 17:58; 25: 3:54,
13:49, 23:45; 26: 9:41, 19:36; 27: 5:32,
15:28; 28: 1:23, 11:19, 21:15
Mar. 1: 7:11, 17:06; 2: 3:02, 12:58,
22:53; 3: 8:49, 18:45; 4: 4:41, 14:36; 5:
0:32, 10:28, 20:23; 6: 6:19, 16:15; 7:
2:10, 12:06, 22:02; 8: 7:57, 17:53; 9:
3:49, 13:45, 23:40; 10: 9:36, 19:32; 11:
5:27, 15:23; 12: 1:19, 11:14, 21:10; 13:
7:06, 17:01; 14: 2:57, 12:53, 22:48; 15:
8:44, 18:40; 16: 4:35, 14:31; 17: 0:27,
10:22, 20:18; 18: 6:14, 16:09; 19: 2:05,
12:01, 21:56; 20: 7:52, 17:48; 21: 3:43,