Sky and Telescope - April 2015 - 39

William Herschel, the Herschels recorded the position of
NGC 4209 as crossing the meridian 1 minute 18 seconds of time after NGC 4196, just 2 minutes to its north.
One minute six seconds of time following, and about 15
minutes south, of NGC 4196 lies the faint galaxy NGC
4211, discovered by Édouard Stephan and described in the
New General Catalogue as "very faint, extremely small,
much brighter to the middle." It's diﬃcult to reconcile the
discrepancy in declination, unless William or Caroline
made a recording error, but could NGC 4211 be Herschel's
missing object?
Two more objects followed quickly - the bright
lenticular galaxy NGC 4251 and the face-on spiral NGC
4275. Sweeping north, Herschel fell into confusion again.
He recorded two fairly bright galaxies, NGC 4278 and
NGC 4283, thinking they were new objects. However,
one month earlier in a sweep two degrees to the north,
he had already come upon these two galaxies, as well as
a fainter one to the east, NGC 4286. The Herschels didn't
notice their error because the two sweeps relied on diﬀerent ﬁeld stars as reference points.
Five more galaxies followed in quick succession: NGC
4310, NGC 4375, NGC 4393, NGC 4448, and NGC
4475. For modern observers, two stand out. NGC 4448
is a bright, barred galaxy with an inner ring structure
that may be visible in very-large-aperture telescopes (8- to
10-inch scopes will reveal a glowing oval, with features
faintly articulated), while NGC 4393 is a large, low surface
brightness spiral with very faint, nebulous knots scattered
across its spiral arms.
William next observed NGC 4556 and NGC 4559.
While NGC 4556 appears nondescript, NGC 4559 has the
distinction of being a large spiral galaxy, the brightest
object recorded that night. William described it as "very

3h 40m

13h 30m

13h 20m
5065

13h 00m

12h 55m

4952

5000

4793

COMA
BERENICES

+28°

4957

+27°

+28°

4874
4927
4921
4869
4923
4911
4840

4961

+29°

4841

4908 IC 4051
4944
4889

4983

4816
4839
4798
4827

13h 10m

13h 05m

+27°
12h 55m

4892

COMA CLUSTER. Herschel spotted NGC 4952, 4966, and 5004 in earlier sweeps
of Coma Berenices. Even so, a wealth of galaxies awaited discovery on April 11, 1785.

bright, very large, much extended north preceding, south
following, 10 or 12′ long, four stars in it." A large aperture
instrument reveals the elongated form and the spiral
sweep of the arms.
William was now on the verge of sweeping through
the heart of the Coma Cluster of galaxies, Abell 1656.
Skimming the northeast outskirts of the cluster the previous month, he had discovered NGC 4952 and NGC 4966
on March 13th. Now he approached the cluster from the
west, where NGC 4692, a small and faint elliptical, stood
in isolation from the group as a whole. He followed this
discovery with the bright spiral NGC 4793, a non-Coma
Cluster galaxy almost two degrees to the north. Swinging
to the south, he picked up another Abell 1656 member,

13h 10m

13h 00m

12h 50m

12h 40m

5057
5056

4966
5000
5263

3h 40m

4966

+29°

5004

5032

5251

13h 05m

5004

5116

4952

COMA
BERENICES

4514

4793
IC 4051
4944 4908 4889
4983
4841
4927
4874
4961 4921
4869 4816
4911
4840
4957 4923
4839
4798
4827
4892

+30°

4495

4559

+28°

4692

4670
4673

4556

+26°
13h 30m

13h 20m

13h 10m

13h 00m

12h 50m

12h 40m

Sk yandTelescope.com April 2015

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Sky and Telescope - April 2015

Table of Contents for the Digital Edition of Sky and Telescope - April 2015