Sky & Telescope - December 2020 - 27

Choice Caldwells for Late Autumn
Caldwell
No.

Object

Type

Common
Name

Constellation

Mag(v)

Size

RA

Dec.

C42

NGC 7006

Globular Cluster

-

Del

10.6

3.6′

21h 01.5m

+16° 11′

C47

NGC 6934

Globular Cluster

-

Del

8.8

7.1′

20h 34.2m

+07° 24′

C6

NGC 6543

Planetary Nebula

Cat's Eye Nebula

Dra

8.1

24″ × 18″

17h 58.6m

+66° 38′

19h

C15

NGC 6826

Planetary Nebula

Blinking Planetary

Cyg

8.8

30″ × 24″

C22

NGC 7662

Planetary Nebula

Blue Snowball

And

8.3

30″

23h 25.9m

+42° 32′

C55

NGC 7009

Planetary Nebula

Saturn Nebula

Aqr

8.0

42″ × 24″

21h 04.2m

-11° 22′

44.8m

+50° 31′

C63

NGC 7293

Planetary Nebula

Helix Nebula

Aqr

7.3

12′ × 10′

22h

C4

NGC 7023

Reflection Nebula

-

Cep

7.7

10′ × 8′

21h 01.6m

+68° 10′

C20

NGC 7000

Emission Nebula

North America Neb.

Cyg

5.0

100′ × 60′

20h 58.8m

+44° 20′

C27

NGC 6888

Emission Nebula

Crescent Nebula

Cyg

8.8

18′ × 13′

20h 12.0m

+38° 21′

7.5

60′ × 8′

20h

56.4m

+31° 43′

45.7m

+30° 43′

C33

NGC 6992/5

Supernova Remnant

Eastern Veil Neb.

Cyg

29.6m

-20° 50′

C34

NGC 6960

Supernova Remnant

Western Veil Neb.

Cyg

7.9

70′ × 6′

20h

C7

NGC 2403

Spiral Galaxy

-

Cam

8.4

24′ × 13′

07h 36.9m

+65° 36′

9.5

9.7′ × 4.5′

22h

37.1m

+34° 25′

47.6m

-25° 17′
-37° 41′

C30

NGC 7331

Spiral Galaxy

-

Peg

C65

NGC 253

Spiral Galaxy

Silver Coin

Scl

7.6

26′ × 6′

00h

C70

NGC 300

Spiral Galaxy

-

Scl

8.1

20′ × 15′

00h 54.9m
00h

C72

NGC 55

Spiral Galaxy

-

Scl

8.1

34′ × 6′

C8

NGC 559

Open Cluster

-

Cas

9.5

7′

01h 29.5m

+63° 18′

C10

NGC 663

Open Cluster

-

Cas

7.1

15′

01h 46.3m

+61° 13′

01h

15.1m

-39° 13′

19.5m

+58° 17′

C13

NGC 457

Open Cluster

ET Cluster

Cas

6.4

20′

C14

NGC 869/884

Open Cluster

Double Cluster

Per

5, 6

18′, 18′

02h 20.5m

+57° 08′

C28

NGC 752

Open Cluster

-

And

5.7

75′

01h 57.6m

+37° 50′

15.0m

+49° 54′
+15° 52′

C16

NGC 7243

Open Cluster

-

Lac

6.4

30′

22h

C41

Melotte 25

Open Cluster

Hyades

Tau

0.5

5.5°

04h 26.9m

Table data are from Stephen O'Meara's book cited in the text. 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.

OPEN CLUSTERS Open star clusters, the final class of deep-sky
objects, are my seasonal favorites, perhaps because their glittering
concentrations of bright stars remind me of holiday lights. The Caldwell
Catalog doesn't disappoint. Start at the eastern end of the W in Cassiopeia, where C8 (NGC 559), C10 (NGC 663), and C13 (NGC 457) all sit
within 5° of each other - easily framed together in most finder scopes
and low-power binoculars. From there, follow the line from Gamma
Cassiopeiae past Delta and onward about twice that distance to find
C14, the famous Perseus Double Cluster (NGC 869 and 884). Now
scan south-southeast nearly 20°, past Gamma Andromedae, to find
C28 (NGC 752), which sprawls over more than 1° and contains stars
that are two billion years old. Then go back to the Milky Way and follow
it westward to Lacerta, the Lizard, to pick up C16 (NGC 7243), which
is only about 1½° west-northwest of 4 Lacertae. Note that C16 sits in
the middle of a shoal of stars that spreads across nearly 10°, from NGC
7296 in the northeast to NGC 7209 in the southwest. The last Caldwell
object on this tour scarcely needs an introduction. The Hyades (C41),
the closest open star cluster to Earth (other than the Ursa Major Moving
Group), is one of the true highlights of autumn and winter skies. Explore
this stellar wonderland with naked eyes, binoculars, and your favorite
telescope - you'll find new things to enjoy at every magnification.

objects and as many Caldwells as possible in a single night.
You can find his search sequence for 40°N at https://is.gd/
mescald. Or why don't you create your own challenge, for
your latitude and observing interests?
The Caldwell Catalog is a reminder that astronomical
observation is a participatory pursuit. For those of us who
enjoy exploring the deep sky, familiar objects always reward
another visit while overlooked targets await our attention.
Every clear night, the adventure begins anew.

¢ Contributing Editor MATT WEDEL thanks Dennis di Cicco,
Rick Fienberg, Tony Flanders, Stephen James O'Meara, Susan
Rose, Stephen Saber, and Roger Sinnott for sharing their
thoughts and memories.
FURTHER RESOURCES: NASA's own Caldwell Catalog is a
collection of photos of more than 50 Caldwell objects taken by the
Hubble Space Telescope; see https://is.gd/hubble_caldwell.
The link to the Astronomical League's Caldwell Challenge is at
https://is.gd/al_caldwell.
sk yandtelescope.org * DECEMBER 2 02 0

27


https://www.is.gd/mescald https://www.is.gd/hubble_caldwell https://www.is.gd/al_caldwell http://www.skyandtelescope.org

Sky & Telescope - December 2020

Table of Contents for the Digital Edition of Sky & Telescope - December 2020

Contents
Sky & Telescope - December 2020 - Cover1
Sky & Telescope - December 2020 - Cover2
Sky & Telescope - December 2020 - 1
Sky & Telescope - December 2020 - Contents
Sky & Telescope - December 2020 - 3
Sky & Telescope - December 2020 - 4
Sky & Telescope - December 2020 - 5
Sky & Telescope - December 2020 - 6
Sky & Telescope - December 2020 - 7
Sky & Telescope - December 2020 - 8
Sky & Telescope - December 2020 - 9
Sky & Telescope - December 2020 - 10
Sky & Telescope - December 2020 - 11
Sky & Telescope - December 2020 - 12
Sky & Telescope - December 2020 - 13
Sky & Telescope - December 2020 - 14
Sky & Telescope - December 2020 - 15
Sky & Telescope - December 2020 - 16
Sky & Telescope - December 2020 - 17
Sky & Telescope - December 2020 - 18
Sky & Telescope - December 2020 - 19
Sky & Telescope - December 2020 - 20
Sky & Telescope - December 2020 - 21
Sky & Telescope - December 2020 - 22
Sky & Telescope - December 2020 - 23
Sky & Telescope - December 2020 - 24
Sky & Telescope - December 2020 - 25
Sky & Telescope - December 2020 - 26
Sky & Telescope - December 2020 - 27
Sky & Telescope - December 2020 - 28
Sky & Telescope - December 2020 - 29
Sky & Telescope - December 2020 - 30
Sky & Telescope - December 2020 - 31
Sky & Telescope - December 2020 - 32
Sky & Telescope - December 2020 - 33
Sky & Telescope - December 2020 - 34
Sky & Telescope - December 2020 - 35
Sky & Telescope - December 2020 - 36
Sky & Telescope - December 2020 - 37
Sky & Telescope - December 2020 - 38
Sky & Telescope - December 2020 - 39
Sky & Telescope - December 2020 - 40
Sky & Telescope - December 2020 - 41
Sky & Telescope - December 2020 - 42
Sky & Telescope - December 2020 - 43
Sky & Telescope - December 2020 - 44
Sky & Telescope - December 2020 - 45
Sky & Telescope - December 2020 - 46
Sky & Telescope - December 2020 - 47
Sky & Telescope - December 2020 - 48
Sky & Telescope - December 2020 - 49
Sky & Telescope - December 2020 - 50
Sky & Telescope - December 2020 - 51
Sky & Telescope - December 2020 - 52
Sky & Telescope - December 2020 - 53
Sky & Telescope - December 2020 - 54
Sky & Telescope - December 2020 - 55
Sky & Telescope - December 2020 - 56
Sky & Telescope - December 2020 - 57
Sky & Telescope - December 2020 - 58
Sky & Telescope - December 2020 - 59
Sky & Telescope - December 2020 - 60
Sky & Telescope - December 2020 - 61
Sky & Telescope - December 2020 - 62
Sky & Telescope - December 2020 - 63
Sky & Telescope - December 2020 - 64
Sky & Telescope - December 2020 - 65
Sky & Telescope - December 2020 - 66
Sky & Telescope - December 2020 - 67
Sky & Telescope - December 2020 - 68
Sky & Telescope - December 2020 - 69
Sky & Telescope - December 2020 - 70
Sky & Telescope - December 2020 - 71
Sky & Telescope - December 2020 - 72
Sky & Telescope - December 2020 - 73
Sky & Telescope - December 2020 - 74
Sky & Telescope - December 2020 - 75
Sky & Telescope - December 2020 - 76
Sky & Telescope - December 2020 - 77
Sky & Telescope - December 2020 - 78
Sky & Telescope - December 2020 - 79
Sky & Telescope - December 2020 - 80
Sky & Telescope - December 2020 - 81
Sky & Telescope - December 2020 - 82
Sky & Telescope - December 2020 - 83
Sky & Telescope - December 2020 - 84
Sky & Telescope - December 2020 - Cover3
Sky & Telescope - December 2020 - Cover4
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/newtrack/st_201612
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