Sky & Telescope - April 2023 - 59
HCG 41
22′ × 22′
HD 86166
6.3
HCG 49
12′ × 12′
BD+68 623
10.3
HCG 52
12′ × 12′
b
a
b
c
d
a
c
BD+21 2319
10.0
a
b
c
d
d
HCG 41
360×, 10′
HCG 49
570×, 5′
of Alpha (α) Ursae Majoris, or Dubhe,
in the Big Dipper. A magnification of
360× readily showed me HCG 49A and
HCG 49B, as well as elongation in the
former. I could only detect HCG 49D
with effort, and HCG 49C not at all.
Upping the magnification to 570×
revealed elongation in B and the small,
round form of C next to it. HCG 49D,
however, remained small and amorphous
even at that magnification. I spotted
a 16th-magnitude star immediately
south of the group. The galaxies' visual
appearances are consistent with their
morphological classification: Components
A and B are evolved spirals, C is an
irregular galaxy, and D is an elliptical.
Let's end our excursion in Leo with
another fine example of a gathering of
galaxies, HCG 52. You'll find it a tad less
than 3° east-northeast of 2.5-magnitude
Delta (δ) Leonis, or Zosma. Three of the
four galaxies in the group are strongly
inclined to our line of sight. HCG 52A is
a barred spiral, and I observed only the
inner part of it at 190× and 310× with
our observatory telescope. I couldn't
resolve the features that are evident in
photographs, such as the bar and a surrounding
ring. HCG 52B appeared much
broader than the needlelike silhouette
that appears in images - a common
visual effect when observing edge-on
galaxies on the threshold of detection.
In these conditions, I only noted the
inner core of HCG 52C, with no hint of
its " garden sprinkler " arms. HCG 52D
is a round puff, barely larger than a star
image but lacking any sharp concentration
toward the middle. Indeed, if you
detect component D at all, you can
congratulate yourself on seeing about as
much as the best digital survey images
reveal in this tiny (a mere 20″ in diameter)
17th-magnitude galaxy.
Denser and better outlined than
typical galaxy clusters, compact galaxy
groups are among the largest cohesive
HCG 52
310×, 10′
structures that we can see with our
own eyes. Observing all the Hickson
groups has remained a challenging
undertaking for visual observers with
big telescopes. Once you start checking
Hicksons off your list, however, you
may not be able to put that list down.
¢ IVAN MALY is a biologist living in upstate
New York. His observing website is
at www.deepskyblog.net.
FURTHER READING: Hickson's original
1982 catalog is at https://is.gd/Hickson_
Catalog and his follow-up work at https://
is.gd/Hickson_Atlas_1993.
Hickson Compact Groups
Object
HCG 36
HCG 39
HCG 41
HCG 47
HCG 49
HCG 52
Anchor Galaxy Mag (Tot)
IC 528
UGC 5057
UGC 5345
UGC 5644
PGC 32899
PGC 35183
12.5
13.9
11.9
12.5
14.4
12.8
Size
1.9′
1.0′
4.1′
2.3′
0.9′
3.2′
RA
Dec
09h 09.4m
09h 29.5m
09h 57.7m
10h 25.8m
10h 56.6m
11h 26.3m
+15° 48′
-01° 21′
+45° 14′
+13° 44′
+67° 11′
+21° 05′
The magnitudes are total for each group. Angular sizes are from recent catalogs. Visually, an object's
size is often smaller than the cataloged value and varies according to the aperture and magnification of
the viewing instrument. Right ascension and declination are for equinox 2000.0.
sk yand tele scope .o r g * APRIL 2023 59
http://www.deepskyblog.net
https://is.gd/Hickson_Catalog
https://is.gd/Hickson_Catalog
https://www.is.gd/Hickson_Atlas_1993
https://www.is.gd/Hickson_Atlas_1993
https://skyandtelescope.org/
Sky & Telescope - April 2023
Table of Contents for the Digital Edition of Sky & Telescope - April 2023
Contents
Sky & Telescope - April 2023 - Cover1
Sky & Telescope - April 2023 - Cover2
Sky & Telescope - April 2023 - 1
Sky & Telescope - April 2023 - Contents
Sky & Telescope - April 2023 - 3
Sky & Telescope - April 2023 - 4
Sky & Telescope - April 2023 - 5
Sky & Telescope - April 2023 - 6
Sky & Telescope - April 2023 - 7
Sky & Telescope - April 2023 - 8
Sky & Telescope - April 2023 - 9
Sky & Telescope - April 2023 - 10
Sky & Telescope - April 2023 - 11
Sky & Telescope - April 2023 - 12
Sky & Telescope - April 2023 - 13
Sky & Telescope - April 2023 - 14
Sky & Telescope - April 2023 - 15
Sky & Telescope - April 2023 - 16
Sky & Telescope - April 2023 - 17
Sky & Telescope - April 2023 - 18
Sky & Telescope - April 2023 - 19
Sky & Telescope - April 2023 - 20
Sky & Telescope - April 2023 - 21
Sky & Telescope - April 2023 - 22
Sky & Telescope - April 2023 - 23
Sky & Telescope - April 2023 - 24
Sky & Telescope - April 2023 - 25
Sky & Telescope - April 2023 - 26
Sky & Telescope - April 2023 - 27
Sky & Telescope - April 2023 - 28
Sky & Telescope - April 2023 - 29
Sky & Telescope - April 2023 - 30
Sky & Telescope - April 2023 - 31
Sky & Telescope - April 2023 - 32
Sky & Telescope - April 2023 - 33
Sky & Telescope - April 2023 - 34
Sky & Telescope - April 2023 - 35
Sky & Telescope - April 2023 - 36
Sky & Telescope - April 2023 - 37
Sky & Telescope - April 2023 - 38
Sky & Telescope - April 2023 - 39
Sky & Telescope - April 2023 - 40
Sky & Telescope - April 2023 - 41
Sky & Telescope - April 2023 - 42
Sky & Telescope - April 2023 - 43
Sky & Telescope - April 2023 - 44
Sky & Telescope - April 2023 - 45
Sky & Telescope - April 2023 - 46
Sky & Telescope - April 2023 - 47
Sky & Telescope - April 2023 - 48
Sky & Telescope - April 2023 - 49
Sky & Telescope - April 2023 - 50
Sky & Telescope - April 2023 - 51
Sky & Telescope - April 2023 - 52
Sky & Telescope - April 2023 - 53
Sky & Telescope - April 2023 - 54
Sky & Telescope - April 2023 - 55
Sky & Telescope - April 2023 - 56
Sky & Telescope - April 2023 - 57
Sky & Telescope - April 2023 - 58
Sky & Telescope - April 2023 - 59
Sky & Telescope - April 2023 - 60
Sky & Telescope - April 2023 - 61
Sky & Telescope - April 2023 - 62
Sky & Telescope - April 2023 - 63
Sky & Telescope - April 2023 - 64
Sky & Telescope - April 2023 - 65
Sky & Telescope - April 2023 - 66
Sky & Telescope - April 2023 - 67
Sky & Telescope - April 2023 - 68
Sky & Telescope - April 2023 - 69
Sky & Telescope - April 2023 - 70
Sky & Telescope - April 2023 - 71
Sky & Telescope - April 2023 - 72
Sky & Telescope - April 2023 - 73
Sky & Telescope - April 2023 - 74
Sky & Telescope - April 2023 - 75
Sky & Telescope - April 2023 - 76
Sky & Telescope - April 2023 - 77
Sky & Telescope - April 2023 - 78
Sky & Telescope - April 2023 - 79
Sky & Telescope - April 2023 - 80
Sky & Telescope - April 2023 - 81
Sky & Telescope - April 2023 - 82
Sky & Telescope - April 2023 - 83
Sky & Telescope - April 2023 - 84
Sky & Telescope - April 2023 - Cover3
Sky & Telescope - April 2023 - Cover4
https://www.nxtbook.com/nxtbooks/aas/st_202410
https://www.nxtbook.com/nxtbooks/aas/st_202409
https://www.nxtbook.com/nxtbooks/aas/st_202408
https://www.nxtbook.com/nxtbooks/aas/st_202407
https://www.nxtbook.com/nxtbooks/aas/st_202406
https://www.nxtbook.com/nxtbooks/aas/st_202405
https://www.nxtbook.com/nxtbooks/aas/st_202404_qr
https://www.nxtbook.com/nxtbooks/aas/st_202404
https://www.nxtbook.com/nxtbooks/aas/st_202403
https://www.nxtbook.com/nxtbooks/aas/st_202402
https://www.nxtbook.com/nxtbooks/aas/st_202401_aus
https://www.nxtbook.com/nxtbooks/aas/st_202401
https://www.nxtbook.com/nxtbooks/aas/st_202312_aus
https://www.nxtbook.com/nxtbooks/aas/st_202312
https://www.nxtbook.com/nxtbooks/aas/st_202311
https://www.nxtbook.com/nxtbooks/aas/st_202310
https://www.nxtbook.com/nxtbooks/aas/st_202309
https://www.nxtbook.com/nxtbooks/aas/st_202308
https://www.nxtbook.com/nxtbooks/aas/st_202307
https://www.nxtbook.com/nxtbooks/aas/st_202306
https://www.nxtbook.com/nxtbooks/aas/st_202305
https://www.nxtbook.com/nxtbooks/aas/st_202304
https://www.nxtbook.com/nxtbooks/aas/st_202304_qr
https://www.nxtbook.com/nxtbooks/aas/st_202303
https://www.nxtbook.com/nxtbooks/aas/st_202302
https://www.nxtbook.com/nxtbooks/aas/st_202301
https://www.nxtbook.com/nxtbooks/aas/st_202212
https://www.nxtbook.com/nxtbooks/aas/st_202211
https://www.nxtbook.com/nxtbooks/aas/st_202210
https://www.nxtbook.com/nxtbooks/aas/st_202209
https://www.nxtbook.com/nxtbooks/aas/st_202208
https://www.nxtbook.com/nxtbooks/aas/st_202207
https://www.nxtbook.com/nxtbooks/aas/st_202206
https://www.nxtbook.com/nxtbooks/aas/st_202205
https://www.nxtbook.com/nxtbooks/aas/st_202204
https://www.nxtbook.com/nxtbooks/aas/st_202203
https://www.nxtbook.com/nxtbooks/aas/st_202202
https://www.nxtbook.com/nxtbooks/aas/st_202201
https://www.nxtbook.com/nxtbooks/aas/st_202112
https://www.nxtbook.com/nxtbooks/aas/st_202111
https://www.nxtbook.com/nxtbooks/aas/st_202110
https://www.nxtbook.com/nxtbooks/aas/st_202109
https://www.nxtbook.com/nxtbooks/aas/st_202108
https://www.nxtbook.com/nxtbooks/aas/st_202107
https://www.nxtbook.com/nxtbooks/aas/st_202106
https://www.nxtbook.com/nxtbooks/aas/st_202105
https://www.nxtbook.com/nxtbooks/aas/st_202104
https://www.nxtbook.com/nxtbooks/aas/st_202103
https://www.nxtbook.com/nxtbooks/aas/st_202102
https://www.nxtbook.com/nxtbooks/aas/st_202101
https://www.nxtbook.com/nxtbooks/aas/skywatch_2021
https://www.nxtbook.com/nxtbooks/aas/st_202012
https://www.nxtbook.com/nxtbooks/aas/st_202011
https://www.nxtbook.com/nxtbooks/aas/st_202010
https://www.nxtbook.com/nxtbooks/aas/st_202009
https://www.nxtbook.com/nxtbooks/aas/st_202008
https://www.nxtbook.com/nxtbooks/aas/st_202007
https://www.nxtbook.com/nxtbooks/aas/st_202006
https://www.nxtbook.com/nxtbooks/aas/st_202005
https://www.nxtbook.com/nxtbooks/aas/st_202004
https://www.nxtbook.com/nxtbooks/aas/st_202003
https://www.nxtbook.com/nxtbooks/aas/st_202002
https://www.nxtbook.com/nxtbooks/aas/st_202001
https://www.nxtbook.com/nxtbooks/aas/st_201912
https://www.nxtbook.com/nxtbooks/aas/st_201911
https://www.nxtbook.com/nxtbooks/aas/st_201910
https://www.nxtbook.com/nxtbooks/aas/st_201909
https://www.nxtbook.com/nxtbooks/aas/st_201908
https://www.nxtbook.com/nxtbooks/aas/st_201907
https://www.nxtbook.com/nxtbooks/aas/st_201906
https://www.nxtbook.com/nxtbooks/aas/st_201905
https://www.nxtbook.com/nxtbooks/aas/st_201904
https://www.nxtbook.com/nxtbooks/aas/st_201903
https://www.nxtbook.com/nxtbooks/aas/st_201902
https://www.nxtbook.com/nxtbooks/aas/st_201901
https://www.nxtbook.com/nxtbooks/aas/st_201812
https://www.nxtbook.com/nxtbooks/aas/st_201811
https://www.nxtbook.com/nxtbooks/aas/st_201810
https://www.nxtbook.com/nxtbooks/aas/st_201809
https://www.nxtbook.com/nxtbooks/aas/st_201808
https://www.nxtbook.com/nxtbooks/aas/st_201807
https://www.nxtbook.com/nxtbooks/aas/st_201806
https://www.nxtbook.com/nxtbooks/aas/st_201805
https://www.nxtbook.com/nxtbooks/aas/st_201804
https://www.nxtbook.com/nxtbooks/aas/st_201803
https://www.nxtbook.com/nxtbooks/aas/st_201802
https://www.nxtbook.com/nxtbooks/aas/st_201801
https://www.nxtbook.com/nxtbooks/aas/st_201712
https://www.nxtbook.com/nxtbooks/aas/st_201711
https://www.nxtbook.com/nxtbooks/aas/st_201710
https://www.nxtbook.com/nxtbooks/aas/st_201709
https://www.nxtbook.com/nxtbooks/aas/st_201708
https://www.nxtbook.com/nxtbooks/aas/st_201707
https://www.nxtbook.com/nxtbooks/aas/st_201706
https://www.nxtbook.com/nxtbooks/aas/st_201705
https://www.nxtbook.com/nxtbooks/aas/st_201704
https://www.nxtbook.com/nxtbooks/aas/st_201703
https://www.nxtbook.com/nxtbooks/aas/st_201702
https://www.nxtbook.com/nxtbooks/aas/st_201701
https://www.nxtbook.com/nxtbooks/aas/st_201612
https://www.nxtbook.com/nxtbooks/aas/st_201611
https://www.nxtbook.com/nxtbooks/aas/st_201610
https://www.nxtbook.com/nxtbooks/aas/st_201609
https://www.nxtbook.com/nxtbooks/aas/st_201608
https://www.nxtbook.com/nxtbooks/aas/st_201607
https://www.nxtbook.com/nxtbooks/aas/st_201606
https://www.nxtbook.com/nxtbooks/aas/st_201605
https://www.nxtbook.com/nxtbooks/aas/st_201604
https://www.nxtbook.com/nxtbooks/aas/st_201603
https://www.nxtbook.com/nxtbooks/aas/st_201602
https://www.nxtbook.com/nxtbooks/aas/st_201601
https://www.nxtbook.com/nxtbooks/aas/st_201512
https://www.nxtbook.com/nxtbooks/aas/st_201511
https://www.nxtbook.com/nxtbooks/aas/st_201510
https://www.nxtbook.com/nxtbooks/aas/st_201509
https://www.nxtbook.com/nxtbooks/aas/st_201508
https://www.nxtbook.com/nxtbooks/aas/st_201507
https://www.nxtbook.com/nxtbooks/aas/st_201506
https://www.nxtbook.com/nxtbooks/aas/st_201505
https://www.nxtbook.com/nxtbooks/aas/st_201504
https://www.nxtbook.com/nxtbooks/aas/st_201503
https://www.nxtbook.com/nxtbooks/aas/st_201502
https://www.nxtbook.com/nxtbooks/aas/st_201501
https://www.nxtbook.com/nxtbooks/aas/st_201412
https://www.nxtbook.com/nxtbooks/aas/st_201411
https://www.nxtbook.com/nxtbooks/aas/st_201410
https://www.nxtbook.com/nxtbooks/aas/st_201409
https://www.nxtbook.com/nxtbooks/aas/st_201408
https://www.nxtbook.com/nxtbooks/aas/st_201407
https://www.nxtbook.com/nxtbooks/aas/st_201406
https://www.nxtbook.com/nxtbooks/aas/st_mars
https://www.nxtbook.com/nxtbooks/aas/st_201405
https://www.nxtbook.com/nxtbooks/aas/st_201404
https://www.nxtbook.com/nxtbooks/aas/st_201403
https://www.nxtbook.com/nxtbooks/aas/st_201402
https://www.nxtbook.com/nxtbooks/aas/st_201401
https://www.nxtbook.com/nxtbooks/aas/st_201312
https://www.nxtbook.com/nxtbooks/aas/st_201311
https://www.nxtbook.com/nxtbooks/aas/st_201310
https://www.nxtbook.com/nxtbooks/aas/st_201309
https://www.nxtbook.com/nxtbooks/aas/st_201308
https://www.nxtbook.com/nxtbooks/aas/st_201307
https://www.nxtbook.com/nxtbooks/aas/st_201306
https://www.nxtbook.com/nxtbooks/aas/st_201305
https://www.nxtbook.com/nxtbooks/aas/st_201304
https://www.nxtbook.com/nxtbooks/aas/st_201303
https://www.nxtbook.com/nxtbooks/aas/st_201302
https://www.nxtbook.com/nxtbooks/aas/st_201301
https://www.nxtbook.com/nxtbooks/aas/st_201212
https://www.nxtbook.com/nxtbooks/aas/st_201211
https://www.nxtbook.com/nxtbooks/aas/st_201210
https://www.nxtbook.com/nxtbooks/aas/st_201209
https://www.nxtbook.com/nxtbooks/aas/st_201208
https://www.nxtbook.com/nxtbooks/aas/st_201207
https://www.nxtbook.com/nxtbooks/aas/st_201206
https://www.nxtbook.com/nxtbooks/aas/st_201205
https://www.nxtbook.com/nxtbooks/aas/st_201204
https://www.nxtbook.com/nxtbooks/aas/st_201203
https://www.nxtbook.com/nxtbooks/aas/st_201202
https://www.nxtbook.com/nxtbooks/aas/st_201201
https://www.nxtbook.com/nxtbooks/aas/st_201112
https://www.nxtbook.com/nxtbooks/aas/st_201111
https://www.nxtbook.com/nxtbooks/aas/st_201110
https://www.nxtbook.com/nxtbooks/aas/st_201109
https://www.nxtbook.com/nxtbooks/aas/st_201108
https://www.nxtbook.com/nxtbooks/aas/st_201107
https://www.nxtbook.com/nxtbooks/aas/st_201106
https://www.nxtbook.com/nxtbooks/aas/st_201105
https://www.nxtbook.com/nxtbooks/aas/st_201104
https://www.nxtbook.com/nxtbooks/aas/st_201103
https://www.nxtbook.com/nxtbooks/aas/st_201102
https://www.nxtbook.com/nxtbooks/aas/st_201101
https://www.nxtbook.com/nxtbooks/aas/st_201012
https://www.nxtbook.com/nxtbooks/aas/st_201011
https://www.nxtbook.com/nxtbooks/aas/st_201010
https://www.nxtbook.com/nxtbooks/aas/st_201009
https://www.nxtbook.com/nxtbooks/aas/st_201008
https://www.nxtbook.com/nxtbooks/aas/st_201007
https://www.nxtbook.com/nxtbooks/aas/st_201006
https://www.nxtbook.com/nxtbooks/aas/st_201005
https://www.nxtbook.com/nxtbooks/aas/st_201004
https://www.nxtbook.com/nxtbooks/aas/st_201003
https://www.nxtbook.com/nxtbooks/aas/st_201002
https://www.nxtbook.com/nxtbooks/aas/st_201001
https://www.nxtbookmedia.com