Sky and Telescope - February 2016 - 31

NGC 2276

ADAM BLOCK / MOUNT LEMMON SKYCENTER / UNIVERSITY OF ARIZONA

NGC 2300

NGC 2300 has a 1.5′ envelope bulging slightly east
and west. The halo condenses sharply to a prominent
core that increases steadily toward the center. With a
fairly high surface brightness, this 12th-magnitude
galaxy should show distinctly through a 6-inch scope
from a dark site. French astronomer Alphonse Borrelly,
a most proﬁcient comet hunter credited with as many as
18 discoveries, identiﬁed this elliptical around 1871 with
a 7.2-inch refractor at the Marseille Observatory.
A 1993 study using the ROSAT X-ray satellite observatory revealed this duo is embedded in an immense cloud
of hot gas about 1 million light-years across and containing roughly 500 billion times the mass of the Sun. As
the leading edge of NGC 2276 plows through the gas,
it triggers vigorous starburst activity. In addition, NGC
2276 has produced 5 supernovae since 1962, the most
recent explosion in 2005. The gas cloud itself should
have dissipated long ago; that it hasn't suggests it's been
held together by the gravity of unseen dark matter.
The 14th-magnitude lenticular galaxy IC 455 is much
smaller and fainter than either member of the previous
pair, but it's a snap to capture about 11′ south-southeast
of NGC 2300. The 35″ × 25″ halo contains a small bright
core punctuated by a star-like nucleus. Search for PGC
21817 approximately 15′ to the east of IC 455. Using
285×, I found a 15″ fuzz spot, though it was easier to

STUDY IN CONTRASTS Halton Arp included this spiral-lenticular pair
in his Atlas of Peculiar Galaxies (1966) largely because of the "somewhat
peculiar" and "perturbed" arms of NGC 2276.

detect than its 15.3 blue magnitude would suggest. This
diminutive glow pins down the northwest vertex of a
quadrilateral formed with three nearby 10.5- to 11thmagnitude stars.
While comet hunting in Cepheus on September 20,
1890, E. E. Barnard ran across IC 455 (as well as NGC
2276 and 2300) using Lick Observatory's 12-inch refractor. Barnard never published his discovery, and the credit
went to accomplished British amateur William Frederick Denning, who found IC 455 less than a month later
with his 10-inch With-Browning reﬂector. Denning is
renowned for his detailed observations of meteor showers, comets, novae, and planets, but he also swept up 15
far northern galaxies while searching for comets.
Several challenging galaxies surround NGC 2276 and
2300. I picked up UGC 3661, a ghostly edge-on, 8′ due
west of NGC 2276. Using averted vision at 225×, I just
glimpsed a phantom streak, roughly 25″ in length and
¼ as wide. Magnitude-14.3 UGC 3654 forms a 4′ pair
to the southwest, but a distracting 13th-magnitude star
attached to its northeast end nearly masks the view. A
close look revealed a tiny 0.3′ nebulous glow extending
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Sky and Telescope - February 2016

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