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CitationSharpless S. (1959) A Catalogue of HII Regions. Astrophys. J. Suppl. Ser. 4, 257.
BibCode1959ApJS....4..257S
DescriptionJournal article

 

A Catalogue of HII Regions

Stewart Sharpless

U.S. Naval Observatory

Received September 10, 1959

[page 257]

Abstract

A catalogue is given of 313 H II regions north of declination −27°. Known early-type stars associated with them are listed. The apparent distribution of H II regions is discussed, and the galactic pole with respect to ionized hydrogen is determined.

I. Introduction

In an earlier paper (Paper I, Sharpless 1953) a catalogue was given of H II regions between galactic longitudes 315° and 105° and extending several degrees on either side of the galactic circle. That survey was based on a series of 48-inch Schmidt plates. As the National Geographic-Palomar Sky Atlas became available, the catalogue was continued on the basis of the Sky Atlas prints, and it now covers the entire sky north of declination −27°. These results, incorporating those of Paper I, are presented here. This catalogue is designed to serve as a finding list for radio and optical astronomers as well as a source of diameters and brief descriptions of H II regions.

The term "H II region" (Stromgren 1948) is used here instead of the term "emission nebula". An H II region is an entity defined not only in terms of the ionized gas but also in terms of the hot stars which are responsible for the ionization. It was in accordance with this principle that the present catalogue was assembled. This method of cataloguing requires judgment as to whether several isolated patches of nebulosity belong to the same H II region. Knowledge of the positions of hot stars responsible for the ionization is usually sufficient to determine this. The distribution of field stars can often reveal the existence of foreground dark lanes which divide an H II region into several apparently detached portions. Those few cases in which an ambiguity still exists are noted as such in the catalogue. An attempt was made to exclude reflection nebulae on the basis of a comparison of the red and blue photographs.

The following sections contain a description of the catalogue, a comparison with previous catalogues, a discussion of the apparent distribution of H II regions, and a determination of the galactic pole with respect to ionized hydrogen.

II. The catalogue

The catalogue is given in Table 1, the columns of which contain the following information:

Column 1.–A running number. An asterisk here indicates a remark at the end of the table.

In this e-version, columns 2 & 3 of Table 1 are not reproduced, and three new columns are added: coordinates brought up to 2000.0, the Notes to the table (p.265) and selected cross-identifications (Table 4, below).

Columns 2, 3.–Galactic co-ordinates based on the Lund pole.

Columns 4, 5.–Equatorial co-ordinates for 1900. The position, measured with respect to a nearby BD star, generally refers to the geometric center of the nebula. If the nebula, however, contains large variations in brightness, an attempt was made to give a position more nearly coinciding with the center of light.

Column 6.–Maximum angular diameter. Owing to the diffuse nature of many of these objects, the diameters given here may have an uncertainty of the order of 20 per cent.

Column 7.–Classification as to form (1 = circular, 2 = elliptical, 3 = irregular).

[continued on page 266 ]

Column 8.–Classification as to structure, ranging from 1 = amorphous to 3 = filamentary.

Column 9.–Classification as to brightness on an arbitrary scale, from 1 = faintest to 3 = brightest.

Column 10.–The number of associated stars as identified in Table 2.

Stars which are associated with these regions and are responsible for their ionization are listed in Table 2. Magnitudes and spectral types are taken from the Henry Draper Catalogue or its extensions. Some stars are listed with no spectral type. Most of these were taken from the finding list of OB stars of Nassau and Morgan (1951), while a few of them are central stars in circular H II regions and are probably the exciting stars although no spectra are available. In the case of regions associated with large aggregates of early-type stars, e.g., Orion, only a partial list of associated stars is given.

[page 258]

Table 1 (edited)

(pp. 258-264)

Table 1
A Catalogue of H II regions

Sh 2-RA (1900) DecDiamFormStructBrightStarsRA (2000) DecNotesOther catalogues
115 52.8, -25 50150323115 58 51, -26 07 14Source of excitation: pi Sco
216 57.3, -38 0060322117 04 06, -38 08 33BBW 31500, Gum 57
317 06.9, -38 2312233017 13 45, -38 30 11Gum 58
417 12.9, -39 145233017 19 48, -39 20 20
517 13.2, -38 21100322917 20 03, -38 27 17Gum 59
617 08.3, -37 004323017 15 04, -37 07 00Gum 60
715 54.4, -22 40240321116 00 19, -22 57 02Source of excitation: delta Sco
817 14.7, -35 56120333417 21 24, -36 02 05BBW 31800, Gum 61, Gum 62, Gum 63, Gum 64, [GS55] 119
916 15.1, -25 2180322116 21 10, -25 35 22Source of excitation: sigma ScoGum 65, [GS55] 118
1017 12.4, -33 5960322117 19 00, -34 05 25
1117 19.9, -34 0790333217 26 31, -34 12 20Gum 66, BBW 32100, [GS55] 120
1217 29.4, -32 32120122917 35 56, -32 35 59Contains cluster NGC 6383Gum 67, BBW 32301, [GS55] 121
1317 24.0, -31 2940222117 30 28, -31 33 46Gum 68, BBW 32300
1417 23.9, -30 112312017 30 18, -30 15 47
1517 44.1, -31 1430222317 50 34, -31 15 51Gum 69, BBW 32603
1617 41.5, -29 1620322017 47 52, -29 18 14Gum 70, BBW 32801
1717 39.8, -28 4925322017 46 08, -28 51 29
1817 42.4, -29 134122017 48 46, -29 15 06BBW 32701
1917 43.0, -29 0512112017 49 21, -29 07 01
2017 42.9, -28 3810322017 49 14, -28 40 02
2117 45.3, -28 525322017 51 39, -28 53 41
2217 48.9, -25 0160322517 55 03, -25 02 10Gum 71, BBW 33402, [GS55] 123
2316 08.0, -08 0750321016 13 24, -08 22 20
2416 05.7, -06 4930212016 11 03, -07 04 38
2517 59.3, -24 24903331418 05 26, -24 23 39M8. Appears to be connected with M20. Part of I Sgr association. Contains cluster NGC 6530.Gum 72, BBW 33402, [GS55] 126
2617 52.9, -23 1920321017 58 59, -23 19 35
2716 31.7, -10 22480322116 37 12, -10 34 11Source of excitation: zeta Oph.Gum 73
2817 56.6, -23 3540121018 02 41, -23 35 03Gum 74, [GS55] 124
2918 04.4, -24 0140322318 10 30, -23 59 55Appears to be connected with M8.Gum 75, [GS55] 130
3017 57.5, -23 0120333118 03 34, -23 00 55M20. Part of II Sgr associationGum 76, BBW 33402, [GS55] 125
3118 05.2, -23 498112118 11 18, -23 47 48
3218 04.8, -23 408122218 10 53, -23 38 51
3315 54.7, -01 2035321015 59 52, -01 37 03
3418 00.4, -21 4090322118 06 24, -21 39 30Gum 77a, [GS55] 129
3518 09.9, -20 1720312518 15 50, -20 15 07Gum 77b, [GS55] 134
3616 00.4, +00 4045121016 05 30, +00 23 40
3718 11.8, -19 4220322318 17 43, -19 39 51Gum 78, BBW 33903, [GS55] 140
3818 02.9, -18 173321018 08 45, -18 16 09
3918 10.9, -18 413312018 16 46, -18 38 59May be part of III Sgr association[GS55] 138
4018 06.2, -17 4615322018 12 02, -17 44 40[GS55] 133
4118 10.0, -18 1690322618 15 51, -18 14 07[GS55] 135
4218 04.5, -16 503312018 10 17, -16 48 55[GS55] 131
4318 10.6, -17 2615212018 16 25, -17 24 02[GS55] 136
4418 10.7, -16 4660322218 16 29, -16 44 01Gum 79, BBW 34101, [GS55] 137
4518 15.0, -16 1360333618 20 46, -16 10 24M17. Two detached portions apparently separated by foreground dark lane.BBW 34202, [GS55] 144, [GS55] 145
4618 00.5, -14 1025222118 06 11, -14 09 31Gum 80, BBW 34201, [GS55] 128
4718 12.0, -15 395122118 17 44, -15 36 50
4818 16.7, -14 3810322118 22 24, -14 35 09Gum 82, BBW 34401, [GS55] 146
4918 13.0, -14 00903331018 18 40, -13 57 42M16. Part of I Ser association. Contans cluster NGC 6611,Gum 83, BBW 34400, [GS55] 142, [GS55] 143
5018 19.8, -14 4635322118 25 30, -14 42 42[GS55] 148
5118 35.0, -16 3935311018 40 46, -16 33 30
5219 41.8, -23 202212019 47 46, -23 05 15May be planetary.
5318 19.6, -13 1715322018 25 14, -13 13 44About six detached portions.[GS55] 147
5418 12.3, -11 46140333718 17 53, -11 43 48Part of II Ser association. Contains cluster NGC 6604.Gum 84, Gum 85, BBW 34600, [GS55] 141
5518 26.6, -11 505321118 32 11, -11 45 44
5618 25.6, -09 477121018 31 06, -09 42 53[GS55] 150
5718 25.1, -08 412321118 30 33, -08 36 57
5818 26.0, -08 328322018 31 27, -08 27 49[GS55] 151
5918 31.6, -07 4120321018 37 01, -07 36 01[GS55] 155
6018 31.3, -06 4720322018 36 41, -06 42 04BBW 35201, [GS55] 154
6118 27.6, -05 052323018 32 55, -05 00 36[GS55] 153
6218 22.3, -03 554311018 27 34, -03 51 22
6319 52.1, -14 2355321019 57 43, -14 06 56
6418 26.4, -01 5925322018 31 35, -01 54 47Appears to be highly obscured[GS55] 152
6518 41.7, -03 517322018 46 58, -03 44 35Contains cluster NGC 6823[GS55] 159
6618 40.3, -02 068322018 45 30, -01 59 47[GS55] 158
6718 44.2, -02 2810211018 49 24, -02 21 13
6818 20.1, +00 488322018 25 11, +00 51 18[GS55] 149
6918 39.3, -00 2320222118 44 26, -00 16 56[GS55] 156
7018 09.8, +07 025312018 14 38, +07 03 47
7118 57.0, +02 013223019 02 02, +02 09 35May be planetary.[GS55] 161
7218 58.8, +02 1025322019 03 50, +02 18 50
7316 06.8, +22 0875321016 11 07, +21 52 26
7419 03.9, +05 273322019 08 49, +05 36 32
7518 54.4, +06 5910121018 59 15, +07 07 12
7618 51.6, +07 417121018 56 25, +07 48 48
7719 43.2, +00 548211019 48 17, +01 08 53
7818 58.6, +13 5912111019 03 11, +14 07 46[GS55] 162
7919 18.7, +13 4740321019 23 18, +13 58 34
8019 07.0, +16 422323019 11 28, +16 51 57May be planetary.
8119 56.5, +11 3110311020 01 13, +11 47 34
8219 25.9, +18 049312119 30 20, +18 16 32[GS55] 163
8319 20.2, +20 362122019 24 32, +20 47 45
8419 44.6, +18 0915323219 49 04, +18 24 01[GS55] 170
8518 59.2, +25 416322119 03 17, +25 49 49
8619 38.9, +23 0340122319 43 09, +23 17 15NGC 6820. Contains cluster. Part of I Vul association.[GS55] 166
8719 42.2, +24 2310311119 46 24, +24 37 41[GS55] 167
8819 41.8, +25 0625322119 45 58, +25 20 38[GS55] 168
8919 45.9, +26 145121019 50 02, +26 29 10[GS55] 172
9019 45.1, +26 376322019 49 13, +26 52 04[GS55] 171
9119 31.6, +29 23120332019 35 34, +29 36 16Very long, thin filament
9219 42.6, +28 0050111419 46 39, +28 14 44[GS55] 169
9319 50.9, +26 571323019 55 01, +27 12 49[GS55] 173
9419 24.0, +31 1625331019 27 51, +31 28 14
9519 51.0, +29 021122019 55 01, +29 17 49
9619 24.9, +32 2925321019 28 42, +32 41 21
9719 52.1, +30 0010121019 56 05, +30 15 57
9819 54.8, +31 0915111119 58 44, +31 25 18
9919 57.0, +33 135323020 00 51, +33 29 34
10019 58.0, +33 144323020 01 51, +33 30 42
10119 56.2, +35 0120322119 59 57, +35 17 28[GS55] 175
10220 27.7, +30 1640311020 31 47, +30 36 19
10320 46.4, +30 33210333020 50 32, +30 55 24The Network Nebula in Cygnus[GS55] 221, [GS55] 222, [GS55] 224, [GS55] 227, [GS55] 228, [GS55] 231, [GS55] 232
10420 14.0, +36 267122020 17 45, +36 44 40May be part of II Cyg association.[GS55] 195
10520 08.4, +38 0318233120 12 02, +38 20 59NGC 6888. Peculiar filamentary structure. May be part of II Cyg association[GS55] 185
10620 23.7, +37 043323020 27 27, +37 23 49
10720 38.9, +35 595222120 42 46, +36 20 34
10820 19.0, +39 56180333020 22 35, +40 15 15gamma Cygni Nebula.
10920 30.0, +40 001080232020 33 38, +40 20 33The Cygnus Nebula. The great size and gross filamentary structure of this nebula set it apart from any known H II regions. The filaments, especially in the region illustrated by Minkowski (1955), bear a striking resemblance to the filaments of IC 443 except for the great difference in angular size. Like IC 443, the Cygnus Nebula is also a strong radio source and has high internal motions (Courtes 1955). Evidently the nebula cannot be considered to be a normal H II region.[GS55] 174, [GS55] 176, [GS55] 177, [GS55] 178, [GS55] 179, [GS55] 180, [GS55] 181, [GS55] 182, [GS55] 183, [GS55] 184, [GS55] 186, [GS55] 187, [GS55] 188, [GS55] 189, [GS55] 190, [GS55] 191, [GS55] 192, [GS55] 193, [GS55] 194, [GS55] 196, [GS55] 197, [GS55] 198, [GS55] 199, [GS55] 200, [GS55] 201, [GS55] 202, [GS55] 203, [GS55] 204, [GS55] 205, [GS55] 206, [GS55] 207, [GS55] 208, [GS55] 210, [GS55] 211, [GS55] 213, [GS55] 214, [GS55] 215, [GS55] 216, [GS55] 217, [GS55] 218, [GS55] 219, [GS55] 220, [GS55] 225, [GS55] 226, [GS55] 233, [GS55] 237, [GS55] 239
11021 16.6, +32 0250321021 20 48, +32 27 28
11121 37.5, +29 3990311021 41 53, +30 06 21
11220 30.5, +45 1915122120 33 50, +45 39 35[GS55] 212
11321 16.8, +37 4015311021 20 48, +38 05 29
11421 17.2, +38 179332021 21 10, +38 42 31[GS55] 242
11520 31.3, +46 3250322020 34 34, +46 52 41
11620 29.1, +47 012122020 32 19, +47 21 25May be planetary.[GS55] 209
11720 55.2, +43 56240332120 58 46, +44 19 19NGC 7000[GS55] 223, [GS55] 229, [GS55] 230, [GS55] 234, [GS55] 236
11821 33.0, +39 46480321021 37 01, +40 12 57[GS55] 243
11921 14.7, +43 31160223121 18 25, +43 56 16[GS55] 240
12021 00.5, +49 291111021 03 47, +49 52 51
12121 01.9, +49 151321021 05 12, +49 38 59
12223 03.8, +14 2340321023 08 47, +14 55 30
12321 38.5, +44 0513222021 42 22, +44 32 24
12421 34.8, +49 5470122021 38 21, +50 21 05[GS55] 244
12521 49.7, +46 489223121 53 33, +47 16 18[GS55] 246
12622 29.0, +38 04160322122 33 27, +38 34 56Part of I Lac association[GS55] 257, [GS55] 258, [GS55] 259
12721 25.5, +54 112322021 28 41, +54 37 15
12821 29.0, +55 251323021 32 08, +55 51 33
12921 09.2, +59 33140322121 11 44, +59 57 41Part of I Cep association[GS55] 238
13020 41.2, +62 523322120 42 59, +63 13 42
13121 35.9, +57 02170122521 39 00, +57 29 09IC 1396. Part of I Cep association.[GS55] 245
13222 15.1, +55 3890332322 18 47, +56 08 05Part of II Cep association[GS55] 252
13321 26.7, +63 5280311021 28 59, +64 18 19
13422 08.1, +58 55160322122 11 29, +59 24 37Isolated patches of nebulosity around lambda Cep.[GS55] 248
13522 18.6, +58 1415322022 22 11, +58 44 18[GS55] 249, [GS55] 251, [GS55] 253
13621 15.0, +67 505323021 16 29, +68 15 11[GS55] 241
13721 54.4, +64 1390321221 57 07, +64 41 37
13822 28.9, +57 581322022 32 39, +58 28 54
13922 31.2, +57 4210321022 35 00, +58 13 02[GS55] 260
14022 15.9, +62 4730223122 19 07, +63 17 07[GS55] 250
14122 25.0, +61 085112022 28 30, +61 38 41[GS55] 256
14222 43.6, +57 3230333322 47 35, +58 03 40Part of II Cep association. Contains cluster NGC 7380.[GS55] 261
14322 46.2, +57 114311022 50 14, +57 42 47[GS55] 263
14422 41.0, +59 224321022 44 52, +59 53 32
14522 22.3, +63 4890221022 25 33, +64 18 31[GS55] 255
14622 45.5, +59 242322022 49 26, +59 55 45[GS55] 262
14722 51.4, +57 562111022 55 29, +58 28 01
14822 52.1, +57 592323022 56 12, +58 31 02[GS55] 265
14922 52.3, +58 001112022 56 24, +58 32 03
15022 27.9, +64 3640322022 31 11, +65 06 50
15122 58.8, +56 3220311123 03 03, +57 04 18[GS55] 269
15222 54.5, +58 152323022 58 37, +58 47 08[GS55] 267
15322 55.1, +58 125122022 59 14, +58 44 10[GS55] 268
15422 47.5, +60 3960322022 51 24, +61 10 50[GS55] 264
15522 52.8, +62 0560322922 56 43, +62 37 04Part of III Cep association.[GS55] 266
15623 01.0, +59 432123023 05 10, +60 15 23[GS55] 270
15723 11.7, +59 3090333523 16 03, +60 02 44Small, very bright condensation in nebula.[GS55] 274, [GS55] 276
15823 09.4, +60 5810233023 13 40, +61 30 40[GS55] 272
15923 11.4, +60 367322023 15 43, +61 08 43[GS55] 275
16023 01.8, +64 0880321323 05 47, +64 40 24[GS55] 271
16123 11.2, +61 1955222023 15 29, +61 51 43[GS55] 273
16223 16.3, +60 3940333223 20 42, +61 11 52NGC 7635. Peculiar elliptical structure near center; similar to No. 298.[GS55] 277
16323 28.7, +60 1410322023 33 19, +60 47 08[GS55] 278
16423 33.7, +59 253322023 38 25, +59 58 14[GS55] 279
16523 35.1, +61 2310222123 39 49, +61 56 15[GS55] 280
16623 37.4, +60 2510111123 42 10, +60 58 17
16723 30.8, +64 182111023 35 22, +64 51 11
16823 48.1, +59 557222023 53 03, +60 28 23[GS55] 281
16923 49.0, +59 495111123 53 58, +60 22 23
17023 56.6, +64 0420122100 01 42, +64 37 24[GS55] 284
17123 59.5, +66 36180323300 04 40, +67 09 24NGC 7822.[GS55] 282, [GS55] 283, [GS55] 285, [GS55] 286
17200 10.2, +60 421211000 15 32, +61 15 21
17300 16.4, +61 1130122200 21 51, +61 44 17[GS55] 3
17423 42.6, +80 2310321023 46 49, +80 56 20
17500 21.7, +64 092122000 27 19, +64 42 13[GS55] 4
17600 26.1, +56 4410321000 31 39, +57 17 09
17700 25.9, +61 5540311200 31 33, +62 28 09[GS55] 5
17822 34.1, +87 15420321022 18 56, +87 45 42
17900 34.6, +62 191111000 40 25, +62 51 58[GS55] 7
18000 42.8, +62 2315311000 48 46, +62 55 45
18100 43.2, +64 4015311000 49 16, +65 12 44
18200 44.2, +64 122311000 50 16, +64 44 42
18300 47.8, +65 1035321000 53 59, +65 42 35
18400 47.0, +56 0440323100 52 50, +56 36 37NGC 281.[GS55] 8
18500 53.9, +60 27120322101 00 00, +60 59 23gamma Cassiopeia Nebula.[GS55] 9
18601 02.5, +62 361322001 08 51, +63 08 03
18701 16.6, +61 2010332001 23 07, +61 51 24[GS55] 11
18801 24.2, +57 519332001 30 39, +58 22 00Crescent-shaped; similar to No. 274.[GS55] 12
18902 04.6, +63 422111002 12 08, +64 10 18
19002 25.8, +61 00150333802 33 23, +61 26 32IC 1805.[GS55] 14, [GS55] 15, [GS55] 16, [GS55] 18
19102 29.2, +59 122313002 36 39, +59 38 14[GS55] 17
19202 39.4, +61 341211002 47 14, +61 59 17[GS55] 21
19302 39.7, +61 352211002 47 32, +62 00 15[GS55] 22
19402 39.5, +61 312212002 47 19, +61 56 16[GS55] 20
19502 32.6, +59 133311002 40 06, +59 38 56
19602 43.4, +61 494112002 51 19, +62 13 53[GS55] 24
19702 34.4, +59 135321002 41 55, +59 38 46[GS55] 19
19802 42.4, +59 179222002 50 01, +59 42 00[GS55] 23
19902 46.8, +60 00120323902 54 33, +60 24 34IC 1848.[GS55] 25, [GS55] 26
20003 02.5, +62 266221103 10 45, +62 48 56
20102 55.3, +60 055323003 03 10, +60 28 42[GS55] 27
20203 10.9, +59 16170321803 18 51, +59 38 02[GS55] 29
20303 14.5, +54 3145121003 22 01, +54 52 40
20403 47.7, +57 0840322003 55 45, +57 25 44
20503 48.5, +52 54120322103 56 08, +53 11 40Part of I Cam association[GS55] 34
20603 55.7, +51 0350323104 03 13, +51 19 46[GS55] 36
20704 12.3, +52 544122004 20 05, +53 08 37[GS55] 42
20804 12.0, +52 441123004 19 45, +52 58 40[GS55] 41
20904 03.5, +50 5414322004 11 03, +51 09 47[GS55] 39
21004 23.2, +52 2020312004 30 59, +52 33 10[GS55] 44
21104 29.3, +50 442323004 36 57, +50 56 22[GS55] 45
21204 33.0, +50 115123004 40 37, +50 22 52[GS55] 46
21304 13.6, +44 411321004 20 43, +44 55 30In cluster.
21404 14.5, +44 084111004 21 34, +44 22 23
21504 10.6, +42 222322004 17 33, +42 36 54
21604 37.6, +46 3880322104 44 57, +46 49 15[GS55] 48
21704 51.3, +47 519222004 58 47, +48 00 20[GS55] 50
21805 33.3, +52 0870211005 41 16, +52 11 18
21904 48.7, +47 143223004 56 08, +47 23 43[GS55] 49
22003 54.1, +36 20320323104 00 38, +36 37 02NGC 1499. Source of excitation: xi Per. Part of II Per association.[GS55] 37
22104 54.3, +46 12120321005 01 40, +46 20 56
22204 23.6, +35 036323004 30 09, +35 16 12
22305 10.1, +42 0670322005 17 11, +42 12 43
22405 20.1, +42 5330332105 27 16, +42 58 16
22505 20.0, +40 3210322005 27 00, +40 37 18
22605 04.3, +37 523323005 11 06, +37 59 33[GS55] 51
22705 13.0, +38 5120322005 19 53, +38 57 19
22805 06.8, +37 208323005 13 35, +37 27 12[GS55] 52
22905 09.7, +34 2165323105 16 19, +34 27 48IC 405.[GS55] 53, [GS55] 54
23005 15.9, +34 02300322005 22 30, +34 07 55Nos. 229 and 234 appear to be superposed on this nebula. May be part of I Aur association.[GS55] 57, [GS55] 58, [GS55] 59, [GS55] 61, [GS55] 69, [GS55] 75
23105 32.6, +35 5212312005 39 19, +35 55 30[GS55] 73
23205 35.7, +36 0940222205 42 26, +36 12 03[GS55] 78
23305 32.0, +35 442322005 38 43, +35 47 35[GS55] 71
23405 21.5, +34 2112323405 28 07, +34 26 07May be part of I Aur association.[GS55] 60
23505 34.3, +35 4810323005 41 01, +35 51 15[GS55] 76
23605 16.0, +33 1655323505 22 33, +33 21 54IC 410. Contains cluster NGC 1893.[GS55] 55
23705 24.8, +34 127323105 31 25, +34 16 38[GS55] 62
23804 16.0, +19 181323004 21 50, +19 32 16T Tauri Nebula.
23904 25.5, +17 545322004 31 17, +18 07 00
24005 34.7, +28 03180132005 41 00, +28 06 13Peculiar filamentary nebula. Radio source.[GS55] 74, [GS55] 77
24105 57.7, +30 1510323006 04 07, +30 14 52
24205 45.6, +26 597122005 51 51, +27 00 39[GS55] 83
24305 33.3, +23 146321005 39 22, +23 17 27
24405 28.5, +21 535233005 34 30, +21 57 09The Crab Nebula.
24503 57.3, +03 51720322204 02 33, +04 07 43
24604 56.5, +13 5765311005 02 09, +14 05 45
24706 02.5, +21 389112106 08 30, +21 37 12[GS55] 85
24806 10.6, +22 3250233406 16 38, +22 30 01IC 443. Highly filamentary; radio source.[GS55] 94, [GS55] 95
24906 14.9, +23 0880322606 20 58, +23 05 23[GS55] 96
25004 34.8, +07 1010321004 40 11, +07 21 46
25104 27.5, +05 3935331004 32 49, +05 51 46
25206 03.7, +20 3140323106 09 39, +20 30 02NGC 2174-75. In I Gem association.[GS55] 84, [GS55] 87
25306 19.8, +20 055311006 25 43, +20 01 41
25406 06.5, +18 0411222106 12 20, +18 02 38[GS55] 88
25506 07.3, +18 003123006 13 08, +17 58 31[GS55] 91
25606 06.8, +17 581322006 12 38, +17 56 35[GS55] 89
25706 07.0, +18 003123006 12 50, +17 58 33[GS55] 90
25806 07.7, +17 571322006 13 32, +17 55 27
25906 05.8, +17 282111006 11 37, +17 26 44
26004 49.8, +05 3022331004 55 07, +05 39 42
26106 03.2, +15 4945322106 08 57, +15 48 07[GS55] 86
26205 01.4, +06 0220321005 06 45, +06 10 04
26305 16.3, +08 1822222105 21 44, +08 23 57[GS55] 56
26405 29.7, +09 52390112905 35 12, +09 56 00Source of excitation: lambda Ori.[GS55] 63, [GS55] 64, [GS55] 82
26505 13.2, +07 2070322005 18 36, +07 26 23
26606 13.1, +15 191223006 18 49, +15 16 40May be planetary.
26706 10.2, +14 184112006 15 53, +14 16 06[GS55] 93
26806 04.6, +13 2160311006 10 15, +13 19 55
26906 08.9, +13 514323006 14 34, +13 49 17[GS55] 92
27006 04.6, +12 501323006 10 13, +12 48 55
27106 09.3, +12 232123006 14 54, +12 21 14
27206 09.4, +12 221212006 15 00, +12 20 13
27306 35.3, +10 002503231106 40 48, +09 54 29NGC 2264. Appears to be connected with No. 275 by lanes of nebulosity.[GS55] 99, [GS55] 100, [GS55] 102, [GS55] 103
27407 23.5, +13 288333007 29 06, +13 15 43NGC 2237-38. Crescent-shaped; similar to No. 188.
27506 26.4, +05 00100123906 31 42, +04 55 47Part of I Mon association. Contains cluster NGC 2244.[GS55] 97, [GS55] 104
27605 22.5, -04 031200222005 27 28, -03 57 55The Barnard Loop. Several detached portions to NE and SW.
27705 35.7, -02 30120323105 40 43, -02 26 50[GS55] 80
27805 14.9, -05 4650322005 19 48, -05 39 49
27905 30.4, -04 5220323105 35 20, -04 48 03[GS55] 67
28006 29.1, +02 3740322406 34 19, +02 32 24[GS55] 98
28105 30.0, -05 3260323305 34 54, -05 28 00NGC 1976, 82. The Orion Nebula.[GS55] 65, [GS55] 66, [GS55] 68
28206 32.8, +01 3635322106 37 59, +01 30 52[GS55] 101
28306 33.5, +00 483311006 38 39, +00 42 46
28406 39.9, +00 2080222006 45 02, +00 13 51
28506 50.1, -00 231123006 55 12, -00 30 37
28606 49.6, -04 236211006 54 33, -04 30 32
28706 54.6, -04 4012322006 59 32, -04 48 14
28807 03.6, -04 091323007 08 33, -04 18 30[GS55] 112
28906 41.1, -07 1411211106 45 56, -07 20 18
29008 48.8, +09 1817222008 54 11, +08 55 16May be planetary.
29106 50.6, -07 548212006 55 25, -08 01 40
29206 59.7, -10 1821323107 04 25, -10 26 56IC 2177. May be connected with No. 296.Gum 1, [GS55] 109
29306 57.1, -11 1011112107 01 47, -11 18 34[GS55] 106
29407 11.8, -09 167323007 16 34, -09 26 38[GS55] 115
29506 58.0, -11 198111107 02 41, -11 27 42[GS55] 107
29607 01.1, -11 042003231007 05 48, -11 13 08Gum 2, [GS55] 108, [GS55] 111, [GS55] 113, [GS55] 114
29707 00.6, -12 117323107 05 15, -12 20 04May be connected with No. 296.Gum 3, [GS55] 110
29807 14.0, -13 0122333107 18 38, -13 11 55Contains peculiar ring structure; similar to No. 162.Gum 4, [GS55] 116
29907 26.1, -15 051311007 30 39, -15 17 34
30007 26.5, -15 123211007 31 03, -15 24 37
30107 05.4, -18 199223007 09 48, -18 28 43Gum 5
30207 27.2, -16 4621212407 31 41, -16 58 43Gum 6
30306 49.8, -22 1890222006 54 01, -22 25 30
30406 39.3, -24 02200322006 43 26, -24 08 00
30507 25.7, -18 194323007 30 08, -18 31 30
30607 26.2, -18 5430321407 30 36, -19 06 34
30707 31.1, -18 326323007 35 32, -18 45 14Gum 7
30806 50.0, -23 4935332106 54 09, -23 56 32
30907 27.7, -19 1312212007 32 06, -19 25 46
31007 08.9, -24 25480322207 13 03, -24 35 11Incomplete ring. Size uncertain due to southern limitation of Palomar Atlas. Contains cluster NGC 2362.Gum 8, [GS55] 117
31107 48.2, -26 1145323207 52 20, -26 26 28Gum 9
31208 54.8, -25 18720322008 59 09, -25 41 19Size uncertain due to southern limitation of Palomar Atlas.
31312 48.2, -22 1912122012 53 31, -22 51 36

[page 265]

Notes to Table 1

(The notes, given below the table in the article, have here been incorporated into Table 1.)

[page 266, continued]

Table 4 is not reproduced here. Entries from this table for the catalogues of Gum, BBW and [GS55] are included in Table 1 (column 8).

Corrections to [GS55] from Table 4:

planetary nebulae: [GS55] 70, 160, 164 & 254.

reflection nebulae: [GS55] 1, 6, 31, 43, 47, 72, 79, 81, 105, 139 & 235.

extragalactic nebulae: [GS55] 2, 10, 13, 28, 30, 32, 33 & 35.

globular clusters: [GS55] 122 & 132.

not visible on Palomar Atlas: [GS55] 40, 157, 165 & 247.

III. PREVIOUS CATALOGUES

Table 3 contains descriptions of previous Hα surveys. The first column gives the reference to the investigation. The next four columns describe the equipment and the spectral region employed for the comparison with the Hα plates. Succeeding columns give the interval of galactic longitudes covered by the investigation, the number of entries contained there-in, and the symbol used here to designate each catalogue in Table 4. Each of the entries of these catalogues, in the respective region of overlap, has been accounted for in terms of the present catalogue numbers in Table 4.

Most of the previous surveys were compiled on the basis of principles similar to those used here. The close agreement of these catalogues with the one given here attests the validity of the cataloguing procedure, especially in view of the large differences in aperture involved. Many of the H II regions listed in Table 1 were not found in the earlier surveys on account of the smaller apertures employed. In general, those regions missed by the earlier survey are those having diameters less than 15′ and low surface brightness. A few discrepancies between the present catalogue and earlier ones result from the fact that some of the previous investigations listed occasional planetary nebulae, reddened extragalactic nebulae, or clusters, since the true nature of these objects was not recognizable on the small-scale plates on which they were found. All such objects are properly identified in Table 4 as follows: 1 = reflection nebula; 2 = galactic cluster; 3 = planetary nebula; 4 = globular cluster; 5 = extragalactic nebula; 6 = not visible on Palomar Atlas.

Several regions listed in Paper I are not included in Table 1. These were visible on original 48-inch Schmidt plates but were not found on the prints. These were omitted for the sake of homogeneity of the catalogue.

IV. THE APPARENT DISTRIBUTION OF H II REGIONS

The apparent distribution of H II regions is shown in Figures 1 through 5. The Network Nebula, the Crab Nebula, and IC 443 have been included, although these are not typical H II regions. The larger regions are represented by hatched areas, while the smaller regions, regardless of shape, are represented by circles.

The features of the apparent distribution discussed in Paper I are even better defined here. The decrease in average angular diameter from l = 315° to l = 5° is in keeping with an inner spiral arm (Sagittarius arm) going off in perspective in the direction of Scutum (Morgan, Whitford, and Code 1953); and the increase in angular sizes from l = 15° to l = 55° agrees qualitatively with the curvature of our own spiral arm (Westerhout 1957). The relative scarcity of nebulae between l = 92° and 102°, and between l = 56° and 66°, is indicative of a rather spotty distribution of H II regions in the Perseus arm. The second gap is apparent also in the distribution of OB stars (Nassau and Morgan 1951) and red supergiants (Nassau and Blanco 1954).

[pp 267-269]

Table 2. A catalogue of associated early-type stars (not reproduced here)

[page 270]

The H II regions between l = 45° and 180° follow the bifurcation of the Orion arm (Morgan, Whitford, and Code 1953; Helfer and Tatel 1955), the nearer branch extending into negative latitudes.

V. THE GALACTIC POLE WITH RESPECT TO IONIZED HYDROGEN

(not reproduced here)

Table 3
PREVIOUS Hα SURVEYS

ReferenceEffective
Aperture
(inches)
f -RatioFilterComparison
Region
Longitude
Interval
nSymbol
Strohmeier (1950)3.91.5AbsorptionBlue150-20042Str.
Sharpless and Osterbrock (1952)0.12AbsorptionRed320-19516Y
Sharpless (1953)482.44AbsorptionBlue315-105142E
Bok, Bester, and Wade (1954)31.5Interference6480 A250-35541B
H. M. Johnson (1955)6.3
5.7
1.2
1.35
Absorption
Interference
Infrared or 6430 A303-203184YM
Gase and Shajn (1955)17.71.4AbsorptionBlue320-195286C
Gum (1955)3.91AbsorptionGreen190-35085G

end

Digitization

Document type: Journal article.

Document source: NASA ADS

Scope: Partial.

Keyed in: AS

Proof reading: AS

Online version: 2010 July 14.

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