Sky & Telescope - March 2024 - 48

MARCH 2024 OBSERVING
Celestial Calendar by Bob King
1275
ΟΣ 53
1342
Algol β
ω
ρ
PERSEUS
24
17
1333
Σ285
21
vdB 16
12
2
3
4
5
6
7
ζ
ε
δ
µ
ρ
T
8
π
U
14
16
38
λ
3h 00m
µ
25 Ari
2h 30m
ξ2
ξ
ξ1
821
2h 00m
ο
12
σ
10
ο
ARIES
M74
660
π
1h 30m
524
Comet 12P/Pons-Brooks
Takes Center Stage
A once (or, twice) in a lifetime visitor returns.
C
omet 12P/Pons-Brooks has been
exciting to watch. Famous for its
unpredictable outbursts, it provided
a first taste of its capriciousness this
apparition when it blew its top on July
20, 2023. Overnight the distant visitor
brightened a hundredfold, morphing
from a 16th-magnitude glimmer into
a fuzzy, 11th-magnitude dot resembling
a small planetary nebula. In the
nights that followed, the solar wind
shaped jets of expelled material into an
uncanny resemblance of the Millennium
Falcon spaceship from Star Wars.
48 MARCH 2024 * SKY & TELESCOPE
Others likened it to a horseshoe crab
or the cartoon character Yosemite Sam.
Additional major outbursts occurred on
October 5th and 31st, and on November
14th. Undoubtedly, additional flares will
occur before you read this.
During March this famous periodic
comet comes into its own and won't
have to rely on outbursts alone to vault
into visibility. Like Halley's Comet,
12P/Pons-Brooks has a short orbital
period and takes just 71 years to circle
the Sun. However, for most of us, this
spring's appearance will likely be the
1h 00m
0h 30m
41
57
η
PISCES
58
34
35
+10°
0h 00m
first and last time we get a look. It starts
the month in western Andromeda just
above the Great Square of Pegasus,
where it glows at a binocular-tempting
7th magnitude. Tracking southeastward,
the comet reaches Aries on the 27th,
when it gains an additional two magnitudes.
Observers under dark, moonless
skies may be able to see the comet without
optical aid as a soft blur among the
stars. Astroimagers will have an enticing
photo opportunity when 12P saunters
some 3° south of the Triangulum Galaxy,
M33, from March 21st to 23rd.
One of the best times to spot the
comet with your naked eye will be at
month's end. On the 30th, the icy interloper
is positioned just ½° northwest of
2nd-magnitude Alpha (α) Arietis, better
known as Hamal. The following night it
sits just a little farther southeast of the
star. And in mid-April the comet passes
6
4
θ
39
41
1156
R
30
α
Hamal
ν
Apr 2
η
31 λ
κ
β
772
γ
ι
Sheratan
107
Mesartim
94 ρ
ψ3
χ
29
35
33
14
10
π
20
W
M34
1003
12
16
1058
14
W
15
R
925
γ
7
δ
ε
TRIANGULUM
6
Σ239
784
IC 1727
672
10
27
25
(c)
φ
η
ψ1
ψ2
66
36
Σ46
55
χ
52
ΟΣ 20
64
Algenib
TV
7814
γ
+20°
φ
ζ
α
91
21
23
υ RT
σ
M33
82
τ
19
15
17 315
68
65
Σ24
ψ
PEGASUS
δ
ε
13
28
Alpheratz
α
85
β
1023
UY
IC 239
58
752
Mirach
π
11
+30°
78
7741
9
55
891
60
γ
Almach
υ
τ
ANDROMEDA ν
µ
β
404
7
V343
c
41
26
Andromeda Galaxy
M110
M32
M31
EG
32
R
ρ σ
3
5 Σ3050
+40°
14
θ
Mar
1
Path of Comet 12P/Pons-Brooks
Star magnitudes
Sky & Telescope - March 2024

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