Sky & Telescope - February 2023 - 49

ness of magnitude 9.5.
A few more comets are expected to
reach magnitude 10 or brighter this
year. If you have a telescope, reasonably
dark skies, and good horizons, you
should be able to see most of these.
February: 96P/Machholz
Amateur astronomer Don Machholz
passed away last August at his home in
Arizona (S&T: Dec. 2022, p. 10). He was
a dedicated and prolific comet hunter,
racking up 12 discoveries in more than
9,000 hours of searching. He nabbed
Comet 96P/Machholz in May 1986,
with his homemade 29×130 binoculars.
The comet's perihelion distance is only
17.4 million km, which is one of the
closest known for a periodic comet.
After reaching that point in its orbit on
January 31st, it swiftly departs the solar
glare while rapidly fading. Northern
Hemisphere observers might glimpse
96P/Machholz glowing at magnitude
8 low in the eastern sky at the start of
morning twilight in early February as it
scoots from Aquarius into Aquila. Catch
it while you can - the comet plunges to
around magnitude 13 by month's end.
June - August: Lemmon
(C/2021 T4)
The best views of Comet Lemmon will
be from tropical and southern latitudes
from late June through late August. As
it brightens from 10th magnitude to
a maximum of 8 in late July, it travels
from southern Cetus to Telescopium.
Observers south of latitude 40° north
should take advantage of a brief window
of visibility from late June through early
July when the comet pops up in Sculptor
low in the southeastern sky before
dawn. After dipping farther south it
swings north and returns into view at
dusk, climbing from Lupus into Libra
during August as it fades.
August - December:
103P/Hartley
NASA's Deep Impact space probe made
a close flyby of Comet 103P/Hartley
back in November 2010. This will be
an excellent apparition, with the comet
reaching magnitude 10 in mid-August
near Beta (β) Andromedae and brightening
to around 8th magnitude in late
September as it crosses from Perseus
through Auriga and into Gemini.
While 103P/Hartley will be visible
before midnight low in the northeast
during the brightest part of its apparition,
you'll see it best before dawn as it
approaches the zenith. It should remain
brighter than magnitude 10 through
early December.
Closest approach to Earth (0.4 a.u.)
occurs on September 26th, and the
comet reaches perihelion on October
12th. Jonathan Shanklin, with
the British Astronomical Association
884
+56°
744
+54°
5
7
+52°
9
PERSEUS
+50°
φ
11
13
+48°
15
φ
17
+46°
19
21
+44°
23
25
γ
+42°
3
+40°
2h 10m
2h 00m
5
1h 40m
1h 30m
1h 20m
1h 10m
sk yand tele scope .o r g * FEBRUARY 2023 49
27
Mar 1
υ
ANDROMEDA
3
θ
2
3
4
5
6
7
8
CASSIOPEIA
869
Feb 1
Comet Section, writes that due to its
relative proximity Hartley will likely
appear quite large and diffuse when it
swings by Earth.
October: 2P/Encke
This famous and frequent visitor
returns this autumn. Watch for
Comet 2P/Encke just before dawn in
early October low in the eastern sky at
around magnitude 10. Although Encke
brightens to 8th magnitude by midOctober,
it becomes increasingly difficult
to see as its altitude decreases and
twilight interferes. Closest approach to
Earth (0.8 a.u.) happens on SeptemPath
o
f Comet ZTF (C/2020 V
2)
Star magnitudes
http://skyandtelescope.org
Sky & Telescope - February 2023

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