Revised New General Catalogue and Index Catalogue

 

Dr. Wolfgang Steinicke, FRAS

 

24 August 2014
 

 


 
 

To my wife Gisela


Pot of all NGC and IC objects (equatorial system). The "clusters" seen are partly due to selection effects (see text)


Preface to the current version

There are new columns for redshift(z), distance (derived from z) and metric distance. All data are arranged in a single line. The amount of objects with status "not found" remains constant (2.3%).

The Revised NGC/IC gives the physical and identification data for each object. Additionally, the Historic NGC/IC is available, presenting the historical data for each object: discoverers, discovery dates, instruments and references in the original NGC and IC (see "NGC/IC" button). It is part of my comprehensive study about the history of the NGC. The results were published in August 2010 by Cambridge University Press: Observing and Cataloguing Nebulae and Star Clusters - From Herschel to Dreyer's New General Catalogue (see "Publications" button).

Unfortunally, I was forced in 2006 to remove all my data from the NGC/IC Project website. This is due to a conflict with the former webmaster Bob Erdman, who eventually has terminated his activities for the project in 2009. His "Historically Corrected NGC", first presented on the project website in April 2006, is a mere copy of my Historic NGC (Jan. 2006) which is evident by an overwhelming amount of facts. The necessary acknowledgment is still missing. Hopefully, a totally revised NGC/IC Project webseite will be launched this year. This offers a chance for a return of my NGC/IC data!

The data of my Revised New General Catalogue and Index Catalogue are used by Mathematica, TheSky, Guide, SkyMapPro, Starry Night, Eye&Telescope, the SAC database and the database of the Losmandy mounting.

Wolfgang Steinicke, Umkirch


Table of contents

1 Introduction

2 The NGC/IC Project

3 Content and structure of the catalogue

3.1 Overwiew

3.2 NGC/IC-numbers, extension letters and components

3.3 Status of identification

3.4 Coordinates and constellations

3.5 Magnitudes, sizes, position angle and type

3.6 Identifications and remarks

4 Literature

 


1 Introduction

The present work contains all objetcs listed in Dreyer's [12] New General Catalogue (NGC), published in 1888 and its two supplements, the Index Catalogue, published in 1895 (IC I), and the Second Index Catalogue, published in 1908 (IC II). The NGC contains 7840 nonstellar objects, the IC I and IC II add another 1520 and 3866 objects, respectively. For a comprehesive history of the NGC, see my latest book.

The historic catalogues collect nonstellar objects, discovered by different observers over the centuries. The history of the NGC/IC is reviewed in detail in my recent book "Observing and Cataloguing of Nebulae and Star Clusters". It is based on my "Historic NGC/IC" datasets. The NGC and the IC I contain all objects found visually up to 1895, regardless of their magnitudes, sizes or various types. This naturally implies a great inhomogeneity. Modern catalogues, e.g. Nilson's UGC [20], are homogenous samples based on precise definitions. Nilson gives also a short survey of the history of catalogues of galaxies (UGC, p. 449). The IC II is of even greater inhomogeneity. The main reason is the advent of photography at the beginning of the century. Beside new nonstellar objects found visually up to 1908, Dreyer included all objects found on plates, taken e.g. by Max Wolf with the Bruce-Astrograph at Heidelberg Observatory. There are crowded "photographic areas" in the IC II, rivaling with real clusters (Virgo, Coma, Fornax; see front cover). A considerable amount of this faint objects (down to 18 mag) are not listed in any modern catalogue, being unverified for a long time.  

Dreyer was aware, that his data contain many errors. He published lists of corrections. Later Reinmuth [25], Carlson [3] and others made corrections. Modern revisions of Dreyer's catalogues were published by Sulentic and Tifft (1977) and by Sinnott (1988). The Revised New General Catalogue (RNGC) by Sulentic and Tifft [29] is an attempt to update the NGC, listing all objects with 1975 positions. Sinnott [27] was the first (exactly 100 years) after Dreyer, who lists the complete NGC/IC with all 13226 objects. His NGC 2000.0 gives positions for the equinox 2000.

My own work starts around 1981 with the compilation of the Revised Index Catalogue, a rather criminalistic work, done by scanning a printed version of Dixon's monumental "Master List" [11]. This sounds rather unscientific, but a digital approach was out of reach at that time. It soon becomes clear that there is a large number of unverified objects and many misidentifications in the literature. A considerable number of IC-objects are identical to existing NGC-objects, and there are IC-objects which appear twice (or even multiple) in the IC. The confusion is due to the fact that the NGC and both IC parts are inhomogenous samples, covering the whole sky independently (sorted by right ascension).

During the revision of the IC, it becomes evident that the same work has to be done for the 7840 NGC-objects. The confusion found in the IC is also present in the NGC and there are disturbing interferences between both catalogues.

Beside the contributions form the NGC/IC Project, which is desribed in the next chapter, identifications of NGC/IC-objects are based on various sources (described in chapter 3), charts and photos. All objects were visually inspected with RealSky [23] or the Digital Sky Survey [24]. For galaxies the major datasets were consulted, e.g. PGC/LEDA [21], UGC [20], MCG [33], CGCG [34], RC3 [10] and NED, the Nasa/IPAC Extragalactic Database and the new DSFG [8]. A number of bright NGC- and IC-galaxies is illustrated in the Carnegie Atlas of Galaxies by Sandage and Bedke [26], which includes all objects listed in the Shapley-Ames catalogue.

The result presented here is not comparable to the work of Sulentic & Tifft or Sinnott, which often failed to clear a confusing case or even totally missed it. Both datasets contain may errors. Examples are given in Steve Gottlieb's Corretions to the RNGC [14] and in Fig. 1. Another one is IC 4274: the NGC 2000.0 gives Decl = -25°, but this must be Decl = -65°, leading to the identity IC 4274 = NGC 5189.

My catalogue contains all available data and cross identifications. Missing or inaccurate data for galaxies (magnitude, size, position angle) were completed. Chapter 3 describes the content and structure of the catalogue and explains the columns (fields). Chapter 4 lists the literature, and the chapters 5 and 6 are the main parts: the data.

 

Fig. 1 - Examples of identified objects.

 
NGC 6993 - The object is declared as "not found" in the RNGC and so the type is "-" in Sinnott's book. But actually NGC 6993 is a bright Sc galaxy (13.8 mag) in Capricornus.
IC 252 - Sinnott does not identify the object (type "blank"), but actually this is a pretty bright double galaxy with a total magnitude of 15.5 mag, located in Cetus. The object is not listed in the PGC or in any other catalogue! The south following lenticular galaxy is "anonymous".
IC 206/207 - Sinnott does not identify both objects (type "blank"). Actually this is a rather "prominent" pair of bright galaxies in Cetus with magnitudes 13.1 mag and 12.8 mag. The (known) identifications are IC 206 = MCG -1-6-53 = PGC 8238 and IC 207 = MCG -1-6-54 = PGC 8251.
 
NGC 678 - This case is based on an identification problem mentioned in the Carnegie Atlas of Galaxies [26], panel 152. The coordinates of the edge-on galaxy named A0147+21 were incorrect, so this interesting object (noted by Allan Sandage) could not be found again. I identified it with NGC 678 = UGC 1280, a bright galaxy (13.3 mag) in Aries, accompanied by NGC 680 and IC 1730.

 


2 The NGC/IC Project

The aim of the NGC/IC project, headed by Dr. Harold G. Corwin jr. (Pasadena/USA), is to clean the historical NGC and IC. All investigations start from the historical data, e.g. the observer's publifications. Dreyer's data are often not consistent. There are puzzles (see e.g. [7], [31]), which are hard to solve, or will never be solved, because the hictorical data are too poor (e.g. the IC 919 group in Ursa Major in the center of galaxy cluster Abell 1783). An example of a solved problem (by Harold Corwin) is NGC 3518, which position was found to be in error by 1h in right ascension, leading to the final identity NGC 3518 = NGC 3110 = NGC 3122.

The present work has been done as part of the project, to get accurate positions and to fill large gaps in the data. Up to now, core team members have presented major contributions to the problem of the NGC/IC identities. Most famous are Malcolm Thomson's Identity Survey of IC Galaxies [31], Harold Corwin's Precise Position List [6] and NGC/IC Puzzle Solutions [7], and Steve Gottlieb's Corrections to the RNGC [14]. Over the last years I checked all objects. Many errors were found by me and others. E.g. IC 3400, listed as a 16.2 mag galaxy, is actually a star of 10 mag! It is often usefull to inspect critical cases by visual observations, as Steve Gottlieb does to simulate the historical situation. In spite of using digital tools like CCD, Internet and CD-ROM in astronomy, the value of visual observing is still high - particularly for the NGC/IC cleaning process! The DSS is often helpfull, but it can cause wrong results. Due to the fact, that the photographic and visual magnitudes of nonstellar objects differ and also that the optical image of diffuse objects looks quite different through a telescope or on a photo.

Although the team member's approach do not totally agree, most identifications are confirmed within the group. But some still vary and this supports many valuable discussions, leading (perhaps) to a final result!
 


3 Content and structure of the catalogues

3.1 Overview

The present work consists of two parts: the Revised New General Catalogue, listing all 7840 NGC-objects and the Revised Index Catalogue, listing all 5386 IC-objects (the first and final objects are shown in Fig. 2 and 3).  

Fig. 2 - The first entries are located in Pegasus: the „classical" pair of galaxies NGC 1 / NGC 2, and IC 1, a pair of stars.
 

Both parts use the same arrangement of columns (fields). The catalogue fields are listed in Tab. 1, discussed in detail in the following sections. Due to the confusion in the original NGC/IC it should be better to talk about entries (or identities), rather than objects. Many entries in the NGC/IC cannot be found or are non-existent, the classical example is NGC 7088, called "Baxendell's unphotographable nebula". The number of existing objects in both catalogues is smaler than the number of entries. A fact which is often ignored by modern computer-telescope databases, used to punch-in the desired object for automatic positioning. In the case of NGC 7088 you will see a blank field, in other cases (see below) you will run into confusion.
 

Tab. 1 - Explanation of the catalogue fields
 
Field Explanation
N Catalogue N = N (NGC) or N = I (IC)
NI catalogue number . Some objects have an extension letter (A,B,C,...).
A Extension letter: A, B, C...
C Components. If two or more different objects use the same NGC- or IC-number, these are numbered as components (1,2,3,...). This is also applied for objects associated with the main entry.
D Dreyer Object. A * marks, that this is the object which is ment in Dreyer's catalogue (many objects with extension letters are not in the original NGC/IC).
S Status. Status of the identification (see Tab. 2)
P Precision. Flag for high precision position
CON Constellation
RH, RM, RS  Right ascension. Equinox J2000.0
V, DG, DM, DS  Declination. Equinox J2000.0
Bmag Photographic (blue) magnitude
Vmag Visual magnitude
B-V Difference of visual and blue magnitude
SB Surface brightness (mag/arcmin2)
x, y Larger/smaller diameter ('). If only one value (a) is given, this refers to the maximum size.
PA Position angle (°). The position angle is only relevant for galaxies, and given if possible.
Type Type of object
z Redshift (from NED or LEDA)
D(z) Distance  derived from z (Mpc)
MD Metric Distance (Mpc); from NED
PGC PGC-number. Object listed in the Catalog of Principle Galaxies [22]
ID1 - ID11 Identifications; the last non-empty field contains remarks (if any)

 

Fig. 3 - The final entries in the catalogues are located in Pisces: NGC 7840 in a small group of NGC-galaxies (all found at Malta by Albert Marth), and the galaxy IC 5386, which is identical to NGC 7832 (seen by Swift and Howe and discovered earlier by William Herschel).
 

3.2 NGC/IC-numbers, extension letters and components

The catalogues are sorted by NGC- and IC-number respectively (taking into account the extension letters). The NGC2000.0 sorts the objects by right ascension, but this is rather awkward, because the precision of the coordinates listed there is rather poor.

There is a considerable number of double/multiple identifications: one object has different NGC- or IC-numbers (or both). Examples are the southern galaxy IC 2624 = NGC 3497 = NGC 3525 = NGC 3528 in the constellation Crater or "Barnard's galaxy" NGC 6822 = IC 4895. All these internal identifications are given in the catalogues.

Even more trouble results from the use of extension letters (e.g. IC 3481A), which were introduced during the last decades to denote new objects in the vincinity, not listed in the original catalogues. In a few cases an original entry is split into two or more names with different extensions, such as NGC 61 in Cetus, which is now NGC 61A and NGC 61B (both are galaxies), or the galaxies in Seyfert's Sextett (NGC 6027A to NGC 6027E = VV 115; the diffuse extension north-west of NGC 6027B was thought by Seyfert to be a sixth galaxy).

In some cases the original name is retained, but extension letters are added to denote fainter objects in the vicinity, e.g. NGC 3250, a galaxy in Antila which is surrounded by 5 companions named NGC 3250A thru NGC 3250E. In one case the extension letter denotes a direction: the "S" in NGC 2175S means "south", denoting a small open cluster east (!) of the emission nebula NGC 2175.

The field C is used to distinguish individual components. Double or multiple systems are split into different components, all with individual data. If extension letters are present, two or more entries are possible, e.g. NGC 78 with C=1 (=NGC 78A), NGC 78 with C=2 (=NGC 78B) and the entries for NGC 78A and NGC 78B itself.

The included entries with extension letters and different components rise the number of objects, while the internal identifications lowers it. The net number (which is by now impossible to calculate) of "real" objects in both catalogues - not regarding the question of existence here - is considerable lower than 13226 (the sum of the original NGC- and IC-entries). The total number of entries in the Revised NGC/ IC is 13957 (see Tab. 2).

Not all objects in the catalogue are in Deyer's original NGC/IC. To assign the identity a * is used in column D.
 

3.3 Status of identification

The field S describes the status of identification, as explained in Tab. 2. Objects with S=1 to 5 are the very NGC/IC objects (sum for NGC: 7059 = 90.0 %, for IC: 4139 = 76.8 %).
 

Tab. 2 - Explanation of the field S and number of entries in the Revised NGC and IC (13226 objects from original catalogue + 731 added objects = 13957).
 

S
Explanation
NGC
%
Add
IC
%
Add
1
Galaxy 6025 76.9 466 3972 73.7 149
2
Galactic nebula, Supernova remnant 148 1.9   86 1.6 4
3
Planetary nebula 94 1.2   36 0.7  
4
Open cluster 673 8.6 3 37 0.7  
5
Globular cluster 116 1.5   8 0.1  
6
Part of other object (e.g. bright HII region of a galaxy) 29 0.4 1 23 0.4  
7
Object already in the NGC- or IC 253 3.2 77 76 1.4 5
8
IC-object already in the NGC     24 264 4.9 2
9
Star(s) 410 5.2   674 12.5  
10
Not found 92 1.1   210 3.9  
  Sum 7840   571 5386   160

 

Objects with S=6 are parts (often bright HII regions) of a large galaxy. Examples are NGC 588, NGC 592, NGC 595 and NGC 604, which are HII regions in M 33 = NGC 598 or IC 3550, 3551, 3552, 3555 and 3563, which are parts of NGC 4559. One could assign these objects a status S=7, which I did not.

If an NGC (or IC) object appears twice or more in the NGC (or IC), all entries with higher NGC (or IC) number carry a status S=7, e.g. NGC 34 (S=7), which is the same as NGC 17 (S=1). All data for these entries are equal. Naturally the "object", e.g. NGC/IC-Number, discovered later, gets the "7". The order for NGC entries is based on the "Historic NGC", presenting the discovery dates.

There is a curious example in the IC, which I call the "Swift-Barnard battle" near Algol: the objects involved are IC 290, 292, 293, 294, 295 and 296, all observed by Swift, and IC 1883, 1884, 1887, 1888 and 1889, all observed by Barnard. Following Corwin [6], the identities are: IC 290 = IC 1884, IC 292 = IC 1887, IC 293 = IC 1888 and IC 294 = IC 296 = IC 1889 which might be also identical to IC 295, further IC 1883 = NGC 1212 (for different view see [31]).

Status S=8 is given for crossover identities bewteen NGC and IC; in the last example: IC 1883 (S=8) and NGC 1212 (S=1). The reverse case is only applied, if the NGC object does not belong to the original set, e.g. NGC 161A (S=8) is identical to IC 1563 (S=1).

Entries with S=9 are single stars, pairs (e.g. the famous pair of stars IC 1 (Fig. 2) in Pegasus; see Fig. 2), trios, groups (asterisms) or clouds of stars. For most single stars a magnitude is given; for the brightest there is a designation (e.g. SAO). Among the record holders (see Tab. 3) is Alpha CVn = NGC 4530. John Herschel suspected some nebulosity around it, which does not exist. Fig. 4 shows the case of the asterism NGC 7005 in Aquarius, discovered by d'Arrest.

Tab. 3 - The brightest stars in the NGC (the record holder in the IC is the 6.5 mag star IC 1851).  

Object
Star
Magnitude (V)
NGC 771 50 Cas 4.0
NGC 4530 Alpha CVn 4.3
NGC 2542 19 Pup 4.7
NGC 2142 3 Mon 5.0

 

Entries with S=10 are not found. Tab. 2 shows, that this applies only to 303 cases (2.3%) in the NGC/IC. Calling these entries "non existent", as the RNGC often does, may be correct. But in some cases, the object could exists at another place, due to observing errors or errors in compiling the NGC/IC. IC 5126 (Fig. 4) in Aquarius is an example. Sinnott does not identify this object (type "blank"). The IC description reads "vF, vS, R, between 2 st 14", which assigns a very faint, very small, round object located between 2 stars of 14 mag. The position is marked with a "+", but there is no object, it exists nearly 1° south.

It is also incorrect to declare the nearest anonymous object as the missing one. As already mentioned, critical cases - also those already "fixed" in the literature - should be carefully investigated with the help of the historical sources. The NGC/IC Project is working on all these "puzzles".

 

Fig. 4 - From left to right: NGC 7005, an asterism in Aquarius (s=9; type: *Grp); IC 5126 in Aquarius (at the nominal position there is no nonstellar object); IC 5126 is a confirmed galaxy at a different position.

 

3.4 Coordinates and constellation

The coordinates are given for the modern equinox 2000.0 (the most northern and southern objects are shown in Fig. 6). The positions for objects with status S=1,6,7,8,9 or 10 are determined with RealSky [23] or DSS [24]. Normally the center of brightness or morphology is used. For large objects (galaxies, star groups or clusters) the center is not well defined. In case of double stars with comparable brightness the geometric center is measured, otherwise the position of the brighter component is given. A total of 12632 accurate positions were measured, flagged by '1' in the field P. Coordinates for globular clusters are from Harris [15]. For planetary nebulae precise coordinates were determined by Brian Skiff [28]. Coordinates for "diffuse" objects like gaseous nebulae or open clusters are adapted from various sources.

With RealSky positions can be measured to an accuracy of 1-2". The result was compared with the Lick Northern Proper Motion Survey Galaxy Calalogue (NPM1G) [18], the new list of MCG positions from Corwin [5], with the GSC and the ESO data [19]. The comparison with the GSC was made by Steve Gottlieb, finding a systematic shift of 2.5" towards the south (Fig. 5 left), due to an internal "problem" of the RealSky software. This shift was corrected.

The comparision with the ESO/Uppsala positions is the first global check of Laubert's measurements in the late 70's (Fig. 5 right). The average values of the absolute differences are 3.8" in Rect and 3.5" in Decl. The center of the cloud is at (+0.2",-2.0"), the shift is also present here! It is also noticable, but with a lower value of 1.5" in the differences RealSky-NPM1G. It seems to me, that the positions determined with the Digital Sky Survey are better.
 
 

Fig. 5 - Coordinate differences in arcsec between this catalogue (RealSky measurements) and the GSC (left) and ESO/Uppsala (right).
 

The constellation is calculated from the borders given by the IAU. Most of the 7840 NGC objects are located in Virgo (678), only 4 NGCs are in Chamaeleon and Equuleus. Most of the 5386 IC objects are located in Coma Berenices (687), no IC is in Circinus and Crux. The following table shows the numbers for all constellations.

 

Con

NGC

IC

Sum

 

Con

NGC

IC

Sum

AND

154

46

200

 

LAC

26

12

38

ANT

49

43

92

 

LEO

385

441

826

APS

8

20

28

 

LEP

32

29

61

AQL

40

8

48

 

LIB

57

19

76

AQR

142

123

265

 

LMI

63

49

112

ARA

16

9

25

 

LUP

18

11

29

ARI

81

66

147

 

LYN

100

36

136

AUR

25

15

40

 

LYR

33

5

38

BOO

264

230

494

 

MEN

72

12

84

CAE

16

7

23

 

MIC

11

19

30

CAM

45

29

74

 

MON

58

9

67

CAP

27

30

57

 

MUS

6

4

10

CAR

40

14

54

 

NOR

14

2

16

CAS

41

17

58

 

OCT

7

8

15

CEN

138

60

198

 

OPH

42

21

63

CEP

36

10

46

 

ORI

65

29

94

CET

409

240

649

 

PAV

49

231

280

CHA

4

3

7

 

PEG

319

114

433

CIR

5

 

5

 

PER

95

60

155

CMA

38

8

46

 

PHE

40

20

60

CMI

19

6

25

 

PIC

20

1

21

CNC

117

220

337

 

PSA

38

17

55

COL

17

8

25

 

PSC

301

172

473

COM

298

687

985

 

PUP

57

7

64

CRA

5

3

8

 

PYX

12

1

13

CRB

37

17

54

 

RET

11

25

36

CRT

87

32

119

 

SCL

61

36

97

CRU

8

 

8

 

SCO

51

15

66

CRV

35

17

52

 

SCT

13

3

16

CVN

212

278

490

 

SER

76

73

149

CYG

70

24

94

 

SEX

66

41

107

DEL

22

7

29

 

SGE

6

2

8

DOR

299

38

337

 

SGR

84

41

125

DRA

301

55

356

 

TAU

48

42

90

EQU

4

11

15

 

TEL

28

87

115

ERI

327

110

437

 

TRA

6

4

10

FOR

67

42

109

 

TRI

82

38

120

GEM

67

47

114

 

TUC

62

62

124

GRU

48

29

77

 

UMA

409

101

510

HER

214

96

310

 

UMI

36

18

54

HOR

25

66

91

 

VEL

36

5

41

HYA

227

136

363

 

VIR

678

502

1180

HYI

11

2

13

 

VOL

9

1

10

IND

43

45

88

 

VUL

20

6

26


 

Fig. 6 - The most northern and most southern entries in the catalogues are both galaxies: NGC 3172 in Ursa Minor ("Polarisima borealis") and NGC 2573 in Octans ("Polarissima australis").

 

3.5 Magnitudes, size, position angle and type

The data for magnitudes, sizes, position angles and types for NGC/IC-objects are incomplete in the literature. Using RealSky and DSS gaps were filled.

The magnitudes listed in the field Bmag are photographic (blue), based on plate inspections/measurements (CGCG, MCG, ESO, DSS and RealSky). The faintest object is shown in Fig. 7. One new source is the NPM1G [18] which gives precise positions and magnitudes. In some cases the magnitudes between PGC, UGC and NPM1G differ by more than 2 mag (the rms-error between PGC and NPM1G is 1.0 mag; mostly the PGC lists the brighter magnitude). In case of a galaxy with compact core and diffuse halo the difference to NPM1G is comprehensible (due to the digital plate measuring process), otherwise the reason is unclear. Examples are IC 983: PGC 12.5 mag, UGC 14.3 mag, NPM1G 14.7 mag or NGC 3074: PGC 13.4 mag, UGC 14.8 mag, NPM1G 16.0 mag.

The magnitudes listed in the field Vmag are visual. If these - in the case of galaxies - are not given in the literature (e.g. the RC3 [10]), Vmag is calculated using the type of the galaxy as described e.g. in the DSFG [8].

The magniude listed in the field SB is the calculated surface brightness for galaxies (see the RC3 [10] or the DSFG [8]).

The data for sizes and position angles, particularly in the IC, are very incomplete (fields a, b and PA). The data given here (together with magnitude estimates) come from inspection of the DSS and RealSky. There are no gaps remaining. The value for "a" gives 0.01' resolution because some planetaries are very small (Fig. 7). If only one the graeter diameter is given, it refers to the maximum size. There is a curiosity concerning the PA in the PGC for MCG galaxies which are neither in the UGC nor in the ESO catalogue: many PA values must be mirrored at 90°. E.g. NGC 4626: the PGC gives PA = 145° but the correct value is PA = 35°, or take NGC 779 (20° to 160°). This was also noticed by Karachentsev [17].
 
 

Fig. 7 - Magnitude (Bmag) and sizes: among the faintest objects is the dwarf galaxy IC 4107 (left), discovered by Wolf, in Coma Berenices with 18.5mag (the brightest object is the open cluster IC 2602 with 1m.9, the "Southern Pleiades" in Carina). Some planetaries are very small, e.g. NGC 6833 in Cygnus (right) with only 1" in diameter (largest object: NGC 292, the Small Magellanic Cloud, with 319' x 205').
 
 

The field Type (see Tab. 4) corresponds to the status and gives further informations. The most complex type information is given for galaxies (e.g. the Hubble type), mainly adapted from UGC, ESO and PGC or detemined by own estimation. Generally types differ between various sources. There is a special type for ring galaxies, following Thompson [30].  Types for open clusters are included according to Trümpler's classification. For globular clusters the concentration class (I...XII) is given.
 

Tab. 4 - Abbreviations used in the field type
 
Type
Explanation 
*, *2,..,*Grp Star, double star,..,star group (asterism)
C, D, E, I, P, S Galaxy: compact, dwarf, elliptical, irregular, peculiar, spiral (d=dwarf, B=bar, R=ring , M=mixed); other letters: from Hubble type or its extensions
R.., PRG Ring galaxy (see [30]), Polar ring galaxy
GxyP Part of galaxy (e.g. bright HII region)
OCL Open cluster (if no Trümpler class is available)
GCL Globular cluster (if no concentration class is available)
DN, EN, RN, PN Nebula: dark, emission, reflection, planetary
SNR  Supernova remnant
NF Not found

 

3.6 Identifications and remarks

The fields ID1, ID2 and ID3 contain cross identifications. If the space is not sufficient, the field Remarks contains additional identifications or a second line (indicated by X=2) is used. The PGC-number is listed in the field PGC (LEDA-numbers are listed as PGC-numbers; numbers > 73197).

All abbreviations are explained in Tab. 5 (see [13] for more details). For the 14002 entries 39096 different identifications are given, coming from 82 catalogues. From these one can see, to which classes the object belongs (e.g. cluster membership, morphology, spectral properties). Some of the problems resulting from these identifications were already discussed, other cases are mentioned below.

Some objects have common names in other catalogues, e.g. galaxies which are members of an interacting group (ARP 317 contains the galaxies NGC 3623, NGC 3627 and NGC 3628). Vice versa there are double entries in one catalogue, e.g. NGC 3627 = ARP 16 = ARP 317. The name ARP 16 refers to the fact, that the galaxy itself is peculiar. The reason why some galaxies have up to three different CGCG-designations, e.g. NGC 1544 = CGCG 361-11 = CGCG 362-4 = CGCG 370-1A (the two polar fields are designated A and B), is due to overlapping Palomar Sky Survey fields inspected individually by Zwicky.

Another example is the galaxy IC1502 = UGC 12105 = UGC 12706 = MCG 12-1-1 = MCG 13-1-2 = CGCG 344-3 = CGCG 359-5 in Cepheus. The object lies on the edge of two MCG-declination zones (at Decl = +75°) and in two different Zwicky-fields, so Vorontsov-Velyaminov and Zwicky included it twice in their catalogues. The double entry in the UGC is probably due to a writing error. UGC 12105 has Rect = 22 34.1 (there is no galaxy at that position) and UGC 12706 (the real IC 1502) has Rect = 23 34.1. UGC 12105 ought to be omitted, but is included here to clarify the situation.
 
 

Tab. 5 - Abbreviations from 82 catalogues used in the fields ID1 to ID11. NGC and IC are not included; PGC (LEDA) is included for completeness. N counts the total occurances in both catalogues (if N=1 the object is given).
 
ID Explanation
N
A Anonymous galaxy form RC2 [9] 21
Abell Planetary nebula
4
AM Arp & Madore (southern peculiar galaxy) 782
ARAK Arakelian (galaxy) 200
ARP Atlas of Peculiar Galaxies [2] 217
BCL Boulesteix cluster (HII region in M33) 7
Berkeley Open cluster 2
Bigourdan Non-stellar object; Bigourdan 298 = NGC 4411-2 1
Bochum Open cluster; Bochum 4 = NGC 2409 1
3C Third Cambridge Catalogue of Radio Sources 22
CED Cederblad (diffuse galactic nebula) 70
CGCG Zwicky's Catalogue of Galaxies and of Clusters of Galaxies [34]; format: first number = field, second number = galaxy in field 6129
CGMW Catalogue of Galaxies Behind the Milky Way 14
COU Coutès (Halpha emission nebula) 2
DCL Dickens, Currie, Lucey (galaxy in centaurus custer) 69
DDO David Dunlop Observatory (dwarf galaxy) 32
DFOT Doi, Fugugita, Okamura, Tarusawa (galaxy in Coma cluster) 9
DG Dorschner & Görtler (reflection nebula) 10
Djorgovsky Globular cluster; Djorgovsky 3 = NGC 6540 1
DRCG Dressler Cluster of Galaxies (galaxis in different clusters) 260
ESO ESO/Uppsala Survey of the ESO(B)-Atlas [19]; format: first number = field, second number = object in field. If the format contains no letters, the object is a galaxy, otherwise letters are used for special types: RN=reflection nebula (e.g. ESO 123-RN7), SC=star cluster, EN=emission nebula, PN=planetary nebula, *N=star(s) in nebula, N*=nebula and star 3029
FAIR Fairall (compact and bright nucleus galaxy) 114
Fath Nebula; Fath 703 = NGC 5892 1
FCC Fornax Cluster Catalogue 42
FGC Flat Galaxy Catalogue (the extension ist FGCE; the addendum is refered by a following 'A') [17] 122
GCL Globular Cluster; from the Catalogue of Star Clusters and Associations 106
HARO Galaxy with UV excess 15
HCG Hickson compact group of galaxies 130
Henize Planetary nebula; Henize 959 = NGC 5408 1
Holmberg Dwarf galaxy; Holmberg VI = NGC 1325A 1
IRAS IRAS catalogue of infrared sources 3391
J Jonkheere (planetary nebula); J 475 = NGC 6741 1
KARA Karachentseva (isolated galaxy) 229
KAZ Kazayan (emission line galaxy) 83
KCPG Karachentsev isolated pair of galaxies  505
KDWG Karachentsev dwarf galaxy 3
Keeler Galaxy; Keeler 690 = NGC 5866A 1
KUG Kiso UV galaxy 672
LBN Lynds Bright Nebula (emission nebula) 101
LDN Lynds Dark Nebula; LDN 1653 = NGC 2313 1
LT L. Thompson [30] (ring galaxy) 2
Lund Open cluster; Lud 1182 = NGC 2175S 1
M Messier; M 110 = NGC 205 is included, M 40 and M 45 are not; all other , except M 24 = IC 4715 and M 25 = IC 4725, are in the NGC 108
MCG Morphological Catalogue of Galaxies [33]; first number = declination zone (+15 to -6, "+" sign is omitted), second number = field in zone (by right ascension), third number = galaxy in field. 7624
Mel Melotte (open cluster); Mel 15 = IC 1805 1
Min Minkowski (planetary nebula); Min 2-57 = NGC 896 1
MK Markarian (galaxy with UV continuum) 277
New Galaxy (Shapley-Ames) 2
NPM1G Lick Northern Proper Motion Survey Galaxy Catalogue [18]; Format: declination zone (°) + number  1705
OCL Open Cluster; from the Catalogue of Star Clusters and Associations 382
Pal Palomar (gobular cluster) 2
PGC (LEDA) Catalog of Principal Galaxies [22]; continued by "Lyon Extragalactic Database" (LEDA) 10381
PHL Palomar-Haro-Luyten (blue star or galaxy); PHL 1226 = IC 1746 1
PK Perek & Kohoutek (planetary nebula) [1]; format: galactic coordinates 134
PRC Polar ring galaxy 43
RB Rood & Baum (galaxy in Coma cluster) 6
Reinmuth Galaxy; Reinmuth 80 = NGC 4517A 1
Reiz Galaxy (this identification is given only if no other identification is available)  35
Ruprecht Open cluster 2
SBS Second Byurakan Survey (UV excess objects) 3
SG Shain & Gaze (emission nebula) 3
Sh2 Sharpless (emission nebula) 19
Shkh Shakhbazian (compact galaxy in compact group) 2
SS Struve & Straka (galactic nebula) 2
1SZ, 2SZ Southern Zwicky compact galaxies (2 lists) 6
Todd Todd (galaxy); found during his „Telescopic Search for the Trans-Neptunian Planet", AN 113, 153 (1885); some new identifications were found by Klaus Wenzel 22
TOL Tololo (emission line galaxy) 9
UGC Uppsala General Catalogue of Galaxies [20] 4012
UGCA Catalogue of Selected Non-UGC Galaxies [21] 170
UM University of Michigan (emission line galaxy) 28
URA Uranova (stellar ring); URA 50 = IC 1311 1
VCC Virgo Cluster Catalog (galaxy) 527
vdB Van den Bergh (reflection nebula); 4
vdB-Hagen Van den Bergh-Hagen (open cluster) 2
VMT Van den Bergh, Marschner, Terzian (supernova remnant); VMT 9 = IC 443 1
VV Vorontsov-Velyaminov (interacting galaxy) [33] 322
WAS Wasilewski (emission line galaxy) 17
Westerlund Open cluster; Westerlund 2 = NGC 3247 1
Z Galaxy listed in the Catalogue of Selected Compact Galaxies and of Post-Eruptive Galaxies [35] only by 1950-coordinates, which are appended. 22
ZH Zwicky-Humason (galaxy in Abell 194); ZH 32 = IC 1693 1
1ZW..7ZW Catalogue of Selected Compact Galaxies and of Post-Eruptive Galaxies [35], based on 7 lists 183
8ZW Eighth List of Compact Galaxies [36] 28
Sum   42494

 

Some objects are misclassified due to their catalogue membership. The planetary nebula IC 3568 is listed in the Uppsala General Catalogue of Galaxies (UGC 7731 = PGC 41662). Visually it is difficult to decide, if the object is a compact galaxy (a typical example is Abell 76) or a small planetary nebula with high surface brightness, e.g. NGC 2242, which was listed by Zwicky as a galaxy (CGCG 205-5). All three examples are shown in Fig. 8 below.


 

Fig. 8 - Classification problems. Left: IC 3568 = UGC 7731 (planetary in Camelopardalis), center: NGC 2242 = CGCG 205-5 (planetary in Auriga), right: Abell 76 (compact galaxy in Aquarius).
 

The field Remarks contains additional identifications and information. In case of a planetary nebula the magnitude of the central star (if known) is given [1]. The field presents also all known individual names for single or multiple objects (see also [16]). In Tab. 6 these names are listed, together with the corresponding object(s). In one case I have created a new name: IC 5173, which I named "Southern Integral-sign", as it looks like the northern "Integral-sign", UGC 3697 (Fig. 9). Unlike UGC 3697, which is a warped galaxy, IC 5173 is a double galaxy (AM 2210-693). Tidal interaction disturbes the larger (left) one. The smaller component is called IC 5173A = ESO 76-IG8A.
 
 

Fig. 9 - The Southern and Northern Integral-signs: IC 5173 = AM 2210-693 in Indus (left) and UGC 3697 in Camelopardalis (see explanation above).
 
 

Tab. 6 - List of names used in the catalogues (field Remarks)
Name Identification
47 Tucanae NGC 104
Ambartsumian's Knot 30" s of NGC 3561
Andromeda Nebula NGC 224 = M 31
Antennae NGC 4038, NGC 4039
Atoms For Peace Galaxy NGC 7252
Barnard's Galaxy NGC 6822 = IC 4895
Barnard's Merope Nebula IC 349
Baxendell's Nebula NGC 7088
Bear Claw/Paw Nebula NGC 2537
Beehive Cluster NGC 2632 = M 44
Black Eye Galaxy NGC 4826 = M 64
Blinking Planetary NGC 6826
Blue Flash Nebula NGC 6905
Blue Planetary NGC 3918
Blue Snowball NGC 7662
Bode's Nebulae NGC 3031 = M 81, NGC 3034 = M 82
Box Nebula NGC 6309
Bubble Nebula NGC 7635
Bug Nebula NGC 6302
Butterfly Nebula IC 2220
Butterly Cluster NGC 6405 = M 6
California Nebula NGC 1499
Carafe Group NGC 1595, NGC 1598 with ESO 202-G23 ("carafe")
Cat Eye Nebula NGC 6543
Centaurus A NGC 5128
Cetus A NGC 1068
Chi Persei NGC 869, NGC 884
Christmas Tree Cluster NGC 2264
Cocoon Nebula IC 5146
Coddington Nebula IC 2574
Copeland Septet NGC 3745, NGC 3746, NGC 3748, NGC 3750, NGC 3751, NGC 3753, NGC 3754
Crab Nebula NGC 1952 = M 1
Crescent Nebula NGC 6888
Double Cluster NGC 869, NGC 884
Dumbbell Nebula NGC 6853 = M 27
Eagle Nebula IC 4703 (in M 16)
Eight-burst Planetary NGC 3132
Epsilon Orionis Nebula NGC 1990
Eskimo Nebula NGC 2392
Eta Carinae Nebula NGC 3372
Flame Nebula NGC 2024
Flaming Star Nebula IC 405
Fornax A NGC 1316
Gamma Cas Nebula IC 59, IC 63
Gamma Cyg Nebula IC 1318
Gem Cluster NGC 3293
Ghost of Jupiter NGC 3242
Grus Quartet NGC 7552, NGC 7582, NGC 7590, NGC 7599
Helix Galaxy NGC 2685
Helix Nebula NGC 7293
Hercules Cluster NGC 6205 = M 13
Herschel's Ray NGC 2736
Hind's Variable Nebula NGC 1555
Horsehead Nebula IC 434
Hubble's Variable Nebula NGC 2261
Intergalactic Wanderer NGC 2419
Jewel Box NGC 4755
Kappa Crucis Cluster NGC 4755
Keenan's System NGC 5216, NGC 5218
Kidney Bean Galaxy NGC 4774
Lagoon Nebula NGC 6523 = M 8
Little Dumbbell NGC 650/51 = M 76
Little Gem NGC 6818
Maia Nebula NGC 1432
Markarian Chain NGC 4374, NGC 4406, NGC 4435, NGC 4438, NGC 4458, NGC 4461, NGC 4473, NGC 4477
Miniature Spiral NGC 3928
Merope Nebula NGC 1435
Mirach's Ghost NGC 404
Nubecula Minor NGC 292 = SMC
North America Nebula NGC 7000
Omega Centauri NGC 5139
Omega Nebula NGC 6618 = M 17
Omikron Velorum Custer IC 2391
Orion Nebula NGC 1976 = M 42
Owl Nebula NGC 3587 = M 97
Papillon IC 708
Pelican Nebula IC 5067, IC 5070
Perseus A NGC 1275
Pinwheel Galaxy NGC 5457 = M 101
Polarissima Australis NGC 2573
Polarissima Borealis NGC 3172
Praesepe NGC 2632 = M 44
Ptolemy's Cluster NGC 6475
Rho Ophiuchi Nebula IC 4604
Ring Nebula NGC 6720 = M 57
Running Chicken Nebula IC 2944
Rosette Nebula NGC 2237, NGC 2238, NGC 2246 (around NGC 2244 = NGC 2239)
Sagittarius Star Cloud IC 4715 = M 24
Saturn Nebula NGC 7009
Sculptor Galaxy NGC 253
Seyfert Sextet NGC 6027 (A-E)
Siamese Twins NGC 4567, NGC 4568
Silver Dollar NGC 253
Small Magellanic Cloud (SMC) NGC 292
Sombrero Galaxy NGC 4594 = M 104
Southern Integral-sign IC 5173
Southern Pleiades IC 2602
Spindle Galaxy NGC 3115
Starqueen Nebula IC 4703 (in M 16)
Stephan's Quintet NGC 7317, NGC 7318A, NGC 7318B, NGC 7319, NGC 7320
Struve's Lost Nebula NGC 1554
Sunflower Galaxy NGC 5055 = M 63
Tarantula Nebula NGC 2070 = 30 Dor
Taurus A NGC 1952 = M 1
The Box NGC 4169, NGC 4173, NGC 4174, NGC 4175
The Eyes NGC 4435, NGC 4438
The Mice NGC 4676A, NGC 4676B
Toby Jug Nebula IC 2220
Triangulum Galaxy NGC 598 = M 33
Trifid Nebula NGC 6514 = M 20
Ursa Major A NGC 3034 = M 82
Veil Nebula NGC 6960, NGC 6992, NGC 6995
Virgo A NGC 4486 = M 87
Whirlpool Galaxy NGC 5194 = M 51
Wild Duck Cluster NGC 6705 = M 11
Witch Head Nebula IC 2118
Zwicky's Triplet IC 3481, IC 3481A, IC 3483

 


4 Literature

[1] Acker, A., et al., Strasbourg-ESO Catalogue of Planetary Nebulae, München 1990; see also: Catalogue of the Central Stars of True and Possible Planetary Nebulae, Strasbourg 1982

[2] Arp, H. C., Atlas of Peculiar Galaxies, Pasadena 1966 (see also: Astrophys. J. Suppl. 14, 1 (1966))

[3] Carlson, D., Some Corrections to Dreyer's Catalogues of Nebulae and Clusters, Astrophys. J. 91 350 (1940)

[4] Corwin, H. G., de Vaucouleurs, A., de Vaucouleurs, G., Southern Galaxy Catalogue, Austin 1985

[5] Corwin, H. G., et al., Accurate Positions for MCG Galaxies, PASP 110, 779 (1998)

[6] Corwin, H. G., Precice Position List, NGC/IC Project, Jan. 2011

[7] Corwin, H. G., NGC/IC Puzzle Solutions, NGC/IC Project, Jan. 2011

[8] Cragin, M., Bonanno, E., Deep Sky Field Guide, Willmann Bell 2001

[9] de Vaucouleurs, G., de Vaucouleurs, A., Corwin, H.C., Second Reference Catalogue of Bright Galaxies, New York 1991

[10] de Vaucouleurs, G., et al., Third Reference Catalogue of Bright Galaxies, New York 1991

[11] Dixon, R. S., Sonneborn, G., A Master List of Nonstellar Optical Astronomical Objects, Ohio State Univ. Press 1980

[12] Dreyer, J. L. E., New General Catalogue, Index Catalogue, Second Index Catalogue, London 1962

[13] Lortet, M.-C., Borde, S., Ochsenbein, F., Astron. Astrophys. Suppl. 107, 193 (1994)

[14] Gottlieb, S., Corrections to the RNGC, NGC/IC Project 1998-2004

[15] Harris W. E., Astron. J. 112, 1487 (1996)

[16] Hirshfeld, A., Sinnott, R. W., Sky Catalogue 2000.0, Vol. 2, Cambridge, Mass. 1985

[17] Karachentsev I. D. et al., Astron. Nachr. 314, 97 (1993)

[18] Klemola A. R., Hanson R. B., Jones B. F., Astron. J. 94, 501 (1987)

[19] Lauberts, A., The ESO/Uppsala Survey of the ESO(B)-Atlas, München 1982

[20] Nilson, P., Uppsala General Catalogue of Galaxies, Uppsala 1973

[21] Nilson, P., Catalogue of Selected Non-UGC Galaxies, Uppsala 1974

[22] Paturel, G., et al., Catalogue of Principal Galaxies, LEDA 2003 (http://leda.univ-lyon1.fr)

[23] RealSky, Astronomical Society of the Pacific, San Francisco, 1996, 1997

[24] The Digized Sky Survey (102 CD-ROM version), Space Telescope Science Institute, 1993

[25] Reinmuth, K., Die Herschel-Nebel, Veröff. Sternwarte Heidelberg, Bd. 9, 1926

[26] Sandage, A., Bedke, J., The Carnegie Atlas of Galaxies, Washington D.C. 1994

[27] Sinnott, R. W., NGC 2000.0, Cambridge University Press, Cambridge, Mass. 1988

[28] Skiff, B., Precise Positions for the NGC/IC Planetary Nebulae, Flagstaff, Arizona 1996

[29] Sulentic, J. W., Tifft, W. G., Revised New General Catalogue of Nonstellar Astronomical Objects, Tuscon 1977

[30] Thompson, L. A ., Astrophys. J. 211, 684 (1977)

[31] Thomson, M. J., Identity Survey of IC Galaxies, NGC/IC Project, 2006

[32] Vorontsov-Velyaminov, B. A., Atlas and Catalogue of Interacting Galaxies, Part I, Moscow 1959 (for Part II see: Astron. Astrophys. Suppl. 28, 1 (1977))

[33] Vorontsov-Velyaminov, B. A., Arkhipova, V. P., Morphological Catalogue of Galaxies, Vol. I-IV, Moskow 1962-1968; see also: Kogoshvili, N. G., Merged Catalogue of Galaxies, Bul. Abastumani Astr. Obs. 46, 133 (1975)

[34] Zwicky, F., et al., Catalogue of Galaxies and of Clusters of Galaxies, Vol. 1-6, Pasadena 1963-68

[35] Zwicky, F., Zwicky, M. A., Catalogue of Selected Compact Galaxies and of Post-Eruptive Galaxies, Zürich 1971

[36] Zwicky, F., Sargent, W. L. W., Kowal C. T., Eighth List of Compact Galaxies, Astron. J. 80, 545 (1975)