Celestial Atlas
(IC 5350 - 5386) ←     NGC Objects: NGC 1 - 49     → (NGC 50 - 99)
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Page last updated Apr 17, 2015
WORKING 16: Working on confused history of discovery

NGC 1 (= PGC 564)
Discovered (Sep 30, 1861) by
Heinrich d'Arrest
A magnitude 12.9 spiral galaxy (type SA(s)b?) in Pegasus (RA 00 07 15.9, Dec +27 42 29)
Historical Identification: Per Dreyer, NGC 1 (= GC 1, d'Arrest, 1860 RA 00 00 04, NPD 63 04.3) is "faint, small, round, between 11th and 14th magnitude stars". The position precesses to RA 00 07 15.8, Dec +27 42 28, within 0.1 arcmin of the center of the galaxy listed above, and there are appropriate stars to the northeast and southwest, so the identification is certain.
Physical Information: Based on a recessional velocity of 4550 km/sec, NGC 1 is about 210 million light years away, in good agreement with redshift-independent distance estimates of 175 to 245 million light years. (Another recessional velocity measurement of 2215 km/sec would place the galaxy only about 100 million light years away, which seems unlikely given the redshift-independent results, so it is probably a misattributed value for a different galaxy, one reason for the effort made on this site to determine what galaxy corresponds to a given designation.) Given that and its apparent size of 2.1 by 1.8 arcmin (counting the fainter outer regions), it is about 130 thousand light years across. Note: Although close in the sky (see the wide-field image below), NGC 1 and 2 are at very different distances; if stars, they would be called an "optical double".
SDSS image of region near spiral galaxy NGC 1, also showing NGC 2 and NGC 7839
Above, a 12 arcmin SDSS image centered on NGC 1, also showing NGC 2 and 7839
Below, a 2.4 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy NGC 1
Below, a 12 arcmin SDSS image centered on NGC 1, also showing NGC 2 and 7839 and PGC 1818016
SDSS image of region near spiral galaxy NGC 1, also showing NGC 2, NGC 7839 and a PGC object

NGC 2 (= PGC 567)
Discovered (Aug 20, 1873) by
Lawrence Parsons, 4th Earl of Rosse
A magnitude 14.2 spiral galaxy (type SABbc?) in Pegasus (RA 00 07 17.1, Dec +27 40 42)
Historical Identification: Per Dreyer, NGC 2 (= GC 6246, 4th Lord Rosse, 1860 RA 00 00 06, NPD 63 06.0) is "very faint, small, south of GC 1" (GC 1 being NGC 1). The position precesses to RA 00 07 17.8, Dec +27 40 46, within 0.2 arcmin of the center of the galaxy listed above, and the galaxy is south of NGC 1, so the identification is certain.
Physical Information: Based on a recessional velocity of 7560 km/sec, a straightforward calculation indicates that NGC 2 is about 350 million light years away, in reasonable agreement with widely varying redshift-independent distance estimates of 260 to 400 million light years. However, for objects at such distances we should take into account the expansion of the Universe during the time it took their light to reach us. Doing that shows that the galaxy was about 340 million light years away at the time the light by which we see it was emitted, about 345 million years ago (the difference between the two numbers being due to the expansion of the intervening space during the light-travel time). Given that and its apparent size of 1.0 by 0.45 arcmin, it is about 100 thousand light years across. Note: Although close in the sky (see the wide-field image of NGC 1), NGC 1 and 2 are at very different distances; if stars, they would be called an "optical double".
SDSS image of spiral galaxy NGC 2
Above, a 1.2 arcmin wide SDSS image of NGC 2; for a wider view, see NGC 1

NGC 3 (= PGC 565)
Discovered (Nov 29, 1864) by
Albert Marth
A magnitude 13.3 spiral galaxy (type S(rs)a? pec) in Pisces (RA 00 07 16.8, Dec +08 18 06)
Historical Identification: Per Dreyer, NGC 3 (= GC 5080, Marth #1, 1860 RA 00 00 06, NPD 82 28) is "faint, very small, round, almost stellar". The position precesses to RA 00 07 16.7, Dec +08 18 46, only 0.7 arcmin north of the galaxy listed above and there is nothing else nearby, so the identification is certain.
Physical Information: Based on a recessional velocity of 3900 km/sec, NGC 3 is about 180 million light years away. Given that and its apparent size of 0.85 by 0.55 arcmin, it is about 45 thousand light years across.
SDSS image of region near spiral galaxy NGC 3, also showing NGC 4, NGC 7838 and NGC 7840
Above, a 12 arcmin wide SDSS image centered on NGC 3, also showing NGC 4, 7838 and 7840
Below, a 1.2 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy NGC 3
Below, a 12 arcmin wide SDSS image centered on NGC 3
Also shown are NGC 4, 7838 and 7840, and PGC 1341667 and 1342413
SDSS image of region near spiral galaxy NGC 3, also showing NGC 4, NGC 7838 and NGC 7840, and some PGC objects

NGC 4 (= PGC 212468)
Discovered (Nov 29, 1864) by
Albert Marth
A magnitude 15.9 lenticular galaxy (type S0/a?) in Pisces (RA 00 07 24.4, Dec +08 22 26)
Historical Identification: Per Dreyer, NGC 4 (= GC 5081, Marth #2, 1860 RA 00 00 16, NPD 82 23) is "extremely faint". The position precesses to RA 00 07 26.7, Dec +08 23 46, over an arcmin north northeast of the galaxy listed above, but there is nothing else nearby, so the identification is certain. However (per Corwin), LEDA listed PGC 620 as NGC 4 because the catalogers did not realize that Marth could see an object as faint as PGC 212468; but Marth was using a telescope of 48 inches aperture (second only to Lord Rosse's 72 inch Leviathan at the time), and he really could have seen a 16th magnitude galaxy. If nothing else, the fact that the errors for Marth 1 and 2 (NGC 3 and 4), which he observed on the same night, are more similar than not proves that he must have seen it. Fortunately, the error in the LEDA database has been corrected, but awareness of the correction is not universal. For instance, a Wikisky search for NGC 4 still shows PGC 620; so for any search the PGC designation or coordinates should be used to ensure an accurate identification of NGC 4, and the incorrect identification as PGC 620 is discussed immediately below as a warning about such things.
Physical Information: NGC 4's apparent size is 0.5 by 0.15 arcmin; apparently nothing else is available.
SDSS image of region near lenticular galaxy NGC 4, also showing NGC 3 and NGC 7840
Above, a 12 arcmin wide SDSS image centered on NGC 4, also showing NGC 3 and 7840
Below, a 0.6 arcmin wide closeup of the galaxy
SDSS image of lenticular galaxy NGC 4
Below, a 12 arcmin wide SDSS image centered on NGC 4; also shown are NGC 3 and 7840, and PGC 73256
SDSS image of region near lenticular galaxy NGC 4, also showing NGC 3, NGC 7840 and PGC 73256

PGC 620 (not =
NGC 4)
Not an NGC object but listed here since sometimes misidentified as NGC 4
A magnitude 17(?) spiral galaxy (type (R)S(rs)a? pec) in Pisces (RA 00 08 18.9, Dec +08 07 16)
Historical Identification: As noted in the entry for NGC 4, PGC 620 is sometimes misidentified as that object; so the purpose of having this entry here instead of on the appropriate PGC page is to provide a warning about that.
Physical Information: Based on a recessional velocity of 5320 km/sec, PGC 620 is about 245 million light years away. Given that and its apparent size of 0.5 by 0.35 arcmin, it is about 35 thousand light years across. Its bright core suggests that it might be a Seyfert galaxy.
SDSS image of region near spiral galaxy PGC 620, which is sometimes misidentified as NGC 4
Above, a 12 arcmin wide SDSS image centered on PGC 620
Below, a 0.6 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy PGC 620, which is sometimes misidentified as NGC 4

NGC 5 (= PGC 595)
Discovered (Oct 21, 1881) by
Édouard Stephan
A magnitude 13.3 lenticular galaxy (type E/S0? pec) in Andromeda (RA 00 07 48.9, Dec +35 21 44)
Historical Identification: Per Dreyer, NGC 5 (Stephan list XII (#1), 1860 RA 00 00 37, NPD 55 25.0) is "very faint, very small, nucleus equivalent to a 13th or 14th magnitude star". The position precesses to RA 00 07 49.7, Dec +35 21 46, only 0.2 arcmin west of the nucleus of the galaxy listed above and within its outer glow, and the nucleus has the stated brightness, so the identification is certain.
Physical Information: Based on a recessional velocity of 5110 km/sec, NGC 5 is about 240 million light years away. Given that and its apparent size of 0.9 by 0.6 arcmin, it is about 60 thousand light years across.
SDSS image of region near elliptical galaxy NGC 5
Above, a 12 arcmin wide SDSS image centered on NGC 5
Below, a 1.5 arcmin wide SDSS image of the galaxy
SDSS image of elliptical galaxy NGC 5

NGC 6 (almost certainly =
NGC 20 = PGC 679)
Discovered (Sep 18, 1857) by R. J. Mitchell (and later listed as NGC 20)
Also observed (Oct 16, 1866) by Herman Schultz (and later listed as NGC 20)
Recorded (Sep 20, 1885) by Lewis Swift (and later listed as NGC 6)
A magnitude 13.1 lenticular galaxy (type E/S0?) in Andromeda (RA 00 09 32.7, Dec +33 18 31)
Historical Identification: Per Dreyer, NGC 6 (Swift list II (#3), 1860 RA 00 01 05, NPD 58 15.6) is "extremely faint, very small, considerably extended". The position precesses to RA 00 08 17.7, Dec +32 31 10, but there is nothing there. However, per Corwin, on the night in question Swift discovered five nebulae (this one and NGC 19, 21, 7831 and 7836) with an average measurement error of 70 seconds of time too far west and 8' 8" too far south, presumably due to improperly setting the setting circles he used to make his measurements at the start of the evening (another galaxy found that same night had a completely different error in position, suggesting that Swift finally realized that the setting circles were "off", and "re-zeroed" them). Applying a corresponding correction to Swift's original measurement yields a position of RA 00 09 28.3, Dec +32 39 19, only a few seconds west of Mitchell's essentially perfect position, but still 39 arcmin too far south. There is the possibility that since Swift used setting circles to measure positions and often misread them, he might have made an error of 40 arcmin in reading the declination circle. Per Corwin it appears that was probably the case here, because Swift's paper states that "one of 5 stars which point to it is pretty near", and there is such a line of stars directly east of NGC 20, the nearest of which is so close to the galaxy that it perfectly fits Mitchell's description of the nebula having an "attached" star, so the equality of the two entries is considered reasonably certain.
Physical Information: Duplicate entries are usually listed under the lowest NGC number, so some references refer to this object as NGC 6; but because of the difficulties involved in identifying it as NGC 6, the galaxy is more often referred to as NGC 20, so see that entry for anything else.
SDSS image centered on Dreyer's position for NGC 6
Above, a 12 arcmin wide SDSS image centered on Dreyer's position for NGC 6
Below, a 12 arcmin wide SDSS image centered on NGC 20, which is almost certainly NGC 6
SDSS image of region near lenticular galaxy NGC 20, also known as NGC 6

NGC 7 (= PGC 627)
Discovered (Sep 27, 1834) by
John Herschel
A magnitude 13.9 spiral galaxy (type SB(s)c?) in Sculptor (RA 00 08 20.8, Dec -29 54 55)
Historical Identification: Per Dreyer, NGC 7 (= GC 2 = JH 4014, 1860 RA 00 01 14, NPD 120 41.2) is "extremely faint, considerably large, much extended, very gradually very little brighter middle". The position precesses to RA 00 08 22.0, Dec -29 54 26, only 0.7 arcmin northeast of the center of the galaxy listed above and within its northern outline, so the identification is certain.
Physical Information: Based on a recessional velocity of 1495 km/sec, NGC 7 is about 70 million light years away, in good agreement with redshift-independent distance estimates of 65 to 75 million light years. Given that and its apparent size of 2.4 by 0.5 arcmin, it is about 50 thousand light years across. It is thought to possibly be a barred spiral, but its edge-on presentation makes classification difficult.
DSS image of region near spiral galaxy NGC 7
Above, a 12 arcmin wide DSS image centered on NGC 7
Below, a 2.4 arcmin wide DSS image of the galaxy
DSS image of spiral galaxy NGC 7
Below, the 12 arcmin wide DSS image at top with labels for other objects in the field of view:
PGC 723295, 724741, 3194215, 3194224 and 3194227, and three quasars:
Q0008027-295632 refers to 2QZJ000802.7-295632, a 20th magnitude quasar with z = 1.590
Q0008265-295750 refers to 2QZJ000826.4-295750, a 21st magnitude quasar with z = 2.038
Q0008274-295423 refers to 2QZJ000827.4-295423, a 20th magnitude quasar with z = 2.061

DSS image of region near spiral galaxy NGC 7, showing labels for a number of other objects in the field of view

NGC 8 (= PGC 648)
Recorded (Sep 29, 1865) by
Otto Struve
A magnitude 15.2 and 16.5 double star in Pegasus (RA 00 08 45.4, Dec +23 50 19)
Historical Identification: Per Dreyer, NGC 8 (= GC 5082, O Struve, 1860 RA 00 01 17, NPD 66 59) is "very faint, nucleus in north end". The position precesses to RA 00 08 29.0, Dec +23 47 46, but there is nothing near the position that is obviously identifiable as Struve's object. However, per Corwin, the pair of stars listed above can be positively identified as NGC 8 by virtue of a comparison with Struve's observation of NGC 9 (which see for an image of both NGC objects), which he discovered two nights earlier. If it is assumed that the positional error for NGC 8 is similar to that for NGC 9, the position falls right on the pair of stars, so the identification is reasonably certain.

NGC 9 (= PGC 652)
Discovered (Sep 27, 1865) by
Otto Struve
A magnitude 13.5 spiral galaxy (type Sab? pec) in Pegasus (RA 00 08 54.7, Dec +23 49 01)
Historical Identification: Per Dreyer, NGC 9 (= GC 5083, O Struve, 1860 RA 00 01 27, NPD 67 00) is "faint, round, 9th or 10th magnitude star to the southeast". The position precesses to RA 00 08 39.1, Dec +23 46 46, but there is nothing there that is obviously identifiable as Struve's object. However, 15 seconds of time to the east and about 2 arcmin to the north, the galaxy listed above seems a reasonable candidate, and (per Corwin) Struve's measurement of the 9th magnitude star 6 arcmin east southeast of the galaxy (the bright star on the left edge of the wide-field image below) makes the identification certain. (It is this identification of NGC 9 with PGC 652 that allows the reasonably certain identification of NGC 8 described in that entry.) Note: The position listed for NGC 9 is for the bright knot on its northeastern rim.
Physical Information: Based on a recessional velocity of 4530 km/sec, NGC 9 is about 210 million light years away, in fair agreement with redshift-independent distance estimates of 115 to 185 million light years. Given that and its apparent size of 0.95 by 0.5 arcmin, it is probably about 60 thousand light years across, but its actual size is as uncertain as its distance.
SDSS image of region near spiral galaxy NGC 9, also showing the double star listed as NGC 8
Above, a 12 arcmin wide SDSS image centered on NGC 9, also showing the double star listed as NGC 8
Below, a 1.0 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy NGC 9

NGC 10 (= PGC 634)
Discovered (Sep 25, 1834) by
John Herschel
A magnitude 12.5 spiral galaxy (type SAB(rs)bc?) in Sculptor (RA 00 08 34.5, Dec -33 51 30)
Historical Identification: Per Dreyer, NGC 10 (= GC 3 = JH 4015, 1860 RA 00 01 28, NPD 124 38.9) is "faint, considerably large, very little extended, gradually little brighter middle". The position precesses to RA 00 08 35.5, Dec -33 52 08, only one second of time east and 0.7 arcmin south of the center of the galaxy listed above and nearly within its outline, so the identification is certain.
Physical Information: Based on its recessional velocity of 6810 km/sec, NGC 10 is about 315 million light years away, in good agreement with redshift-independent distance estimates of 235 to 365 million light years. Given that and its apparent size of 2.2 by 1.2 arcmin, it is about 200 thousand light years across.
DSS image of region near spiral galaxy NGC 10
Above, a 12 arcmin wide DSS image centered on NGC 10
Below, a 2.4 arcmin wide DSS image of the galaxy
DSS image of spiral galaxy NGC 10
Below, another 2.4 arcmin wide image of the galaxy (Image Credit ESO 1-meter Schmidt telescope)
ESO image of spiral galaxy NGC 10
Below, the 12 arcmin wide DSS image at top, also showing a number of PGC objects
(PGC 669409, 671426, 3168904, 3168909 and 3168915)
DSS image of region near spiral galaxy NGC 10, also showing a number of PGC objects

NGC 11 (= PGC 642)
Discovered (Oct 24, 1881) by
Édouard Stephan
A magnitude 13.7 spiral galaxy (type Sa?) in Andromeda (RA 00 08 42.5, Dec +37 26 53)
Historical Identification: Per Dreyer, NGC 11 (Stephan list XII (#2), 1860 RA 00 01 29, NPD 53 19.9) is "very faint, very small, very little extended, 2 very faint stars involved". The position precesses to RA 00 08 42.4, Dec +37 26 52, right on the galaxy listed above, so the identification is certain.
Physical Information: Based on a recessional velocity of 4390 km/sec, NGC 11 is about 205 million light years away, in fair agreement with redshift-independent distance estimates of 165 to 195 million light years. Given that and its apparent size of 1.65 by 0.5 arcmin, it is about 100 thousand light years across.
SDSS image of region near spiral galaxy NGC 11, overlaid on a DSS image to fill in missing areas
Above, a 12 arcmin wide SDSS image centered on NGC 11, overlaid on a DSS image to cover missing areas
Below, a 1.6 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy NGC 11

NGC 12 (= PGC 645)
Discovered (Dec 6, 1790) by
William Herschel
Also observed (Oct 16, 1827) by John Herschel
A magnitude 13.1 spiral galaxy (type SAB(rs)c?) in Pisces (RA 00 08 44.7, Dec +04 36 45)
Historical Identification: Per Dreyer, NGC 12 (= GC 4 = JH 1 = WH III 868, 1860 RA 00 01 34, NPD 86 10.2) is "extremely faint, pretty large, very gradually little brighter middle". The position precesses to RA 00 08 44.6, Dec +04 36 34, within 0.2 arcmin of the center of the galaxy listed above and well within its outline, so the identification is certain.
Physical Information: Based on a recessional velocity of 3940 km/sec, NGC 12 is about 185 million light years away, in fair agreeement with a single redshift-independent distance estimate of 155 million light years. Given that and its apparent size of 1.6 by 1.3 arcmin, it is about 85 thousand light years across.
SDSS image of region near spiral galaxy NGC 12
Above, a 12 arcmin wide SDSS image centered on NGC 12
Below, a 2 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy NGC 12
Below, a 12 arcmin wide SDSS image centered on NGC 12, also showing PGC 212475 and 1269991
SDSS image of region near spiral galaxy NGC 12, also showing a couple of PGC objects

NGC 13 (= PGC 650)
Discovered (Nov 26, 1790) by
William Herschel
Also observed (Nov 16, 1827) by John Herschel
A magnitude 13.2 spiral galaxy (type (R)Sab?) in Andromeda (RA 00 08 47.7, Dec +33 25 59)
Historical Identification: Per Dreyer, NGC 13 (= GC 5 = JH 2 = WH III 866, 1860 RA 00 01 35, NPD 57 20.8) is "very faint, very small, small star plus nebulosity". The position precesses to RA 00 08 48.0, Dec +33 25 58, within 0.1 arcmin of the center of the galaxy listed above, so the identification is certain.
Physical Information: Based on a recessional velocity of 4810 km/sec, NGC 13 is about 225 million light years distant, in reasonable agreement with redshift-independent distance estimates of 180 to 215 million light years. Given that and its apparent size of 2.2 by 0.45 arcmin, it is about 145 thousand light years across.
SDSS image of region near spiral galaxy NGC 13
Above, a 12 arcmin wide SDSS image centered on NGC 13
Below, a 2.4 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy NGC 13

NGC 14 (= PGC 647 =
Arp 235)
Discovered (Sep 18, 1786) by William Herschel
Also observed (Nov 2, 1823) by John Herschel
A magnitude 12.1 irregular galaxy (type (R)IB(s)m? pec) in Pegasus (RA 00 08 46.2, Dec +15 48 58)
Historical Identification: Per Dreyer, NGC 14 (= GC 7 = JH 3 = WH II 591, 1860 RA 00 01 37, NPD 74 57.9) is "very faint, pretty small, round, gradually little brighter middle". The position precesses to RA 00 08 48.5, Dec +15 48 52, two seconds of time east of the center of the galaxy listed above but within its outline, so the identification is certain.
Physical Information: Based on a recessional velocity of 865 km/sec, NGC 14 is about 40 million light years distant, in perfect agreement with a single redshift-independent distance estimate of the same value. Given that and its apparent size of 2.7 by 2.1 arcmin, it is about 30 thousand light years across. Its structure is ill-defined, but it appears to be either an irregular galaxy or a weakly barred "diffuse" spiral galaxy. NGC 14 is used by the Arp Atlas as an example of a galaxy with the appearance of fission.
SDSS image of region near irregular galaxy NGC 14, also known as Arp 235
Above, a 12 arcmin wide SDSS image centered on NGC 14
Below, a 3 arcmin wide SDSS image of the galaxy
SDSS image of irregular galaxy NGC 14, also known as Arp 235
Below, a 1 by 1.3 arcmin wide "raw" HST image of part of the galaxy (Image Credit Hubble Legacy Archive)
'Raw' HST image of part of irregular galaxy NGC 14, also known as Arp 235
Below, the 12 arcmin wide SDSS image above with labels for several fainter galaxies and a quasar:
Q0008568+155046 refers to SDSSJ000856.79+155045.7, a 19th magnitude quasar with z = 1.691
SDSS image of region near irregular galaxy NGC 14, also known as Arp 235, also showing labels for several other objects

NGC 15 (= PGC 661)
Discovered (Oct 30, 1864) by
Albert Marth
A magnitude 13.8 spiral galaxy (type SAB(r)a?) in Pegasus (RA 00 09 02.5, Dec +21 37 29)
Historical Identification: Per Dreyer, NGC 15 (= GC 5084, Marth #3, 1860 RA 00 01 50, NPD 69 10) is "very faint, very small, round, brighter middle". The position precesses to RA 00 09 02.0, Dec +21 36 46, which is only 0.7 arcmin south of the galaxy listed above and there is nothing else in the field, so the identification is certain.
Physical Information: Based on a recessional velocity of 6330 km/sec, NGC 15 is about 295 million light years away, in good agreement with redshift-independent distance estimates of 295 to 415 million light years. Given that and its apparent size of 1.05 by 0.6 arcmin, it is about 90 thousand light years across.
SDSS image of region near spiral galaxy NGC 15
Above, a 12 arcmin wide SDSS image centered on NGC 15
Above, a 1.2 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy NGC 15

WORKING HERE: Need to check math, edit for typos and clarity
Also need to review all of WH & JH's original papers (per Corwin)

NGC 16 (= PGC 660)
Discovered (Sep 8, 1784) by
William Herschel
Also observed (Sep 5, 1828) by John Herschel
A magnitude 12.0 lenticular galaxy (type E/SAB0?) in Pegasus (RA 00 09 04.3, Dec +27 43 46)
Historical Identification: Per Dreyer, NGC 16 (= GC 8 = GC 12 = JH 4 = JH 5 = WH IV 15, 1860 RA 00 01 52, NPD 63 03.0) is "pretty bright, small, round, brighter middle". The equivalence of GC 8 (= JH 4) and GC 12 (= JH 5) is discussed in a note at the end of the NGC: "(John Herschel's) h5 (= GC 12) was not seen by d'Arrest and Stephan (XIII); it is = h4 (= GC 8) as they were observed in different sweeps." The position precesses to RA 00 09 04.6, Dec +27 43 46, almost dead center on the galaxy listed above, so the identification is certain.
Discovery Notes: When John Herschel published his "General Catalog", GC 8 was defined as JH 4, and GC 12 was defined as JH 5 and assumed equal to WH IV 15; and since Dreyer published the NGC it has been assumed that GC 12 = GC 8 = NGC 16. However, in 2014 it was suggested that JH 5 and WH IV 15 are not observations of NGC 16, but of some faint star or perhaps even NGC 22. That suggestion is almost certainly wrong, as discussed in the lengthy analysis below; and in any event the identification of NGC 16 as PGC 660 is unaffected by any question about its discovery. So unless you want to read all the details confirming the history of discovery, you can skip that discussion by clicking here.
   Analysis of John Herschel's GC 8 = JH 4: John Herschel's GC lists #8 = JH 4 as "pretty bright, small, round, brighter middle", with a position of (1860) RA 00 01 52.1, NPD 63 03 27.5, which precesses to RA 00 09 04.7, Dec +27 43 18, less than half an arcmin south of the center of NGC 16 and within its southern outline, so the identification of GC 8 with that object is certain. Since the JH numbers are in order of the date of observation, JH 4 is the earlier of the two observations in question, and its date of observation (Sep 5, 1828) is the correct one for John Herschel's first observation of NGC 16, regardless of the status of JH 5.
   Analysis of William Herschel's IV 15: Per William Herschel's first catalog of 1000 nebulae and clusters, WH IV 15 was observed on Sep 8, 1784 as "A faint star with small chevalure and 2 burs." at a position 2m 6s east and 1° 21' south of 21 (α) Andromedae, or Alpheratz. However, Dr. Corwin has provided me with a copy of the last five observations Herschel took on the night in question, from a "fair copy" made by his sister, Caroline Herschel. That shows that he actually recorded offsets of 2m 6s east and 1° 23' south of 21 Andromeda, and adds other items of interest. Specifically, he noted the rising of the nearly last quarter Moon about half an hour before to stopped observing (presumably because even at that phase the Moon's light would make it difficult to see the faintest objects visible under dark-sky conditions, and the last thing he observed was the very faint object listed as WH IV 15). In the interim Herschel observed three stars: a 7th magnitude star, 21 Andromedae and 85 Pegasi. Since the positions of 21 And and 85 Peg are known, they can both be used to calculate the position of WH IV 15, and in the process provide some information about how consistent Herschel's measurements were on the night in question.
      Calculations Using 21 Andromedae: For 21 Andromedae the offsets are 2m 6s east and 1° 23' south. The modern position of Alpheratz is RA 00 08 23.3, Dec +29 05 26, with proper motions of +0.13746"/year in right ascension and -0.16344"/year in declination. This means that in 1784 its J2000 position was 2.0s west and 35" north of its present position, or at RA 00 08 21.3, Dec +29 06 01. This precesses to (1784) RA 23 57 15.7, Dec +27 53 51, and applying Herschel's offsets for IV 15, whatever he observed should be located near (1784) RA 23 59 21.7, Dec +26 30 51. This precesses to J2000 RA 00 10 28.6, Dec +27 43 00, in a completely stellar region about 1m 24s east and 0.8 arcmin south of NGC 16, and about 40s east and 7 arcmin south of NGC 22.
      Calculations Using 85 Pegasi, and a Comparison of the Results: For 85 Pegasi, the offsets for IV 15 are 8m 18s east and 34' north. The modern position of 85 Pegasi is RA 00 02 10.2, Dec +27 04 56, with proper motions of +0.78022"/year in right ascension and -0.91775"/year in declination, meaning that in 1784 its J2000 position was 11.2s west and 3' 7" north of its present position, or at RA 00 01 59.0, Dec +27 08 03. This precesses to (1784) RA 23 50 57.5, Dec +25 55 54, and applying Herschel's offsets, whatever he observed should be located near (1784) RA 23 59 15.5, Dec +26 29 54. This precesses to J2000 RA 00 10 22.2, Dec +27 42 03, only a few seconds of time and an arcmin away from the position obtained from comparison with 21 Andromedae, and since William Herschel only recorded right ascensions to the nearest tenth of a minute of time and declinations to the nearest arcmin, "errors" of up to 0.2 minutes of right ascension and 2 arcmin of declination could be recorded even if the observations themselves were absolutely perfect. For example, consider the 7th-magnitude star recorded by Herschel 1.5 minutes before 85 Pegasi, at an NPD 15' south of that star. That must be the magnitude 6.5 star HD 224758, which had a position in 1784 (using similar methods of calculation and rounding to the same accuracy as Herschel's measurements) 1.5 minutes west and 13' south of 85 Pegasi, within the range of rounding errors stated above, verifying that for all practical purposes the position of WH IV 15 is exactly the same regardless of which comparison star is used.
   Analysis of John Herschel's GC 12 = JH 5 (declared = WH IV 15 in the GC): John Herschel's GC lists #12 = JH 5 = WH IV 15 as "very faint, very small, stellar" with a position of (1860) RA 00 03 14.6, NPD 63 04 58.5, which precesses to RA 00 10 27.8, Dec +27 41 46, in the same completely stellar region as the elder Herschel's positions, and in fact less than an arcmin from the average position (RA 00 10 25.4, Dec +27 42 31) of the two values for WH IV 15 calculated above, making its position exactly the same to the accuracy of the earlier observations. So there can be no doubt that JH 5 = WH IV 15, as stated in the GC.
   What Is GC 12 = JH 5 = WH IV 15?: NGC 16 and NGC 22 are the only objects reasonably close to the positions obtained above, so one of those galaxies is almost certainly what the Herschels observed. And the answer is almost certainly NGC 16, since its declination is almost exactly the same as that measured by the Herschels, while NGC 22 is over 7 arcmin to the north, which is a far less likely error than a minute or so of right ascension in historical observations, and NGC 16 is far brighter. Admittedly, the recorded magnitudes of the two galaxies only differ by a factor of 4 in brightness, which appears to agree with the difference in the description of GC 8 as "very bright" and GC 12 as "very faint", but that is for their entire extent as recorded by modern photographs. For visual observers only the bright core is visible, and the large bright core of NGC 16 is many times brighter than the much smaller, fainter core of NGC 22. In fact, there is considerable doubt whether William Herschel could have seen NGC 22 even under the best of conditions, let alone in the growing light accompanying even a nearly quarter Moon rising in the eastern sky. So we are left with three options: (1) Assume that GC 12 represents an observation of a nonexistent object, despite the fact that the Herschels' essentially identical positions suggest they must have seen something, (2) assume that GC 12 represents an observation of NGC 22, despite the fact that it was probably just as hard for them to see as a nonexistent object and the large error in declination is hard to accept, or (3) assume as Dreyer did that GC 12 = GC 8 = NGC 16. Given these choices I see no reason to abandon Dreyer's suggestion, and feel reasonably comfortable accepting the probable fact that GC 12 is simply one of many examples in which the Herschels misrecorded the right ascension of an object.
   (Temporary) Final Discovery Note: Although the discussion above covers everything available for William Herschel's observation, it only relies on the published record for John Herschel's observation, and there are additional original data available for that. Per Corwin, those original data are very confused. It looks like JH probably made a minute of time error in recording his position, and if William did the same thing (which cannot be known, since there is nothing left to review for his observation), the identification with NGC 16 becomes certain. But since I have not had time to review JH's records in detail, even though I am already essentially convinced of the identification with NGC 16, the warning that I am still working on this entry will remain in place for a little while.
Physical Information: Based on a recessional velocity of 3100 km/sec, NGC 16 is about 145 million light years away, in fair agreement with redshift-independent distance estimates of 105 to 120 million light years. Given that and its apparent size of 1.9 by 1.1 arcmin, it is about 80 thousand light years across. NGC 16 appears to be a completely isolated galaxy, at least 20 million light years from any other galaxy of significant size.
SDSS image of region near lenticular galaxy NGC 16, also showing the double star listed as NGC 18
Above, a 12 arcmin wide SDSS image centered on NGC 16, also showing the double star listed as
NGC 18
Below, a 2 arcmin wide SDSS image of the galaxy
SDSS image of lenticular galaxy NGC 16
Below, a 12 arcmin wide SDSS image centered on NGC 16
Also shown are NGC 18, PGC 655 and PGC 1814072 and 1816642
SDSS image of region near lenticular galaxy NGC 16, also showing the double star listed as NGC 18 and several PGC objects

NGC 17 (=
NGC 34 = PGC 781)
Discovered (1886) by Frank Muller (and later listed as NGC 17)
Discovered (Nov 21, 1886) by Lewis Swift (and later listed as NGC 34)
Also observed (Jul 1, 1899 to Jun 30, 1900) by Herbert Howe (proving NGC 17 = NGC 34)
A magnitude 14.4 spiral galaxy (type S? pec) in Cetus (RA 00 11 06.6, Dec -12 06 27)
Historical Identification: Per Dreyer, NGC 17 (Muller list II (#276), 1860 RA 00 01 58, NPD 102 54.0) is "very faint, extremely small, irregularly round, double star 2 arcmin to west". The position precesses to RA 00 09 07.3, Dec -12 07 14, which is 2 minutes of right ascension (about half a degree) west and nearly an arcmin south of the galaxy listed above, but (per Howe) the double star two arcmin west of the galaxy firmly establishes its identity with NGC 34 (which see for a discussion of the double listing).
Physical Information: Based on a recessional velocity of 5880 km/sec, NGC 17 is about 275 million light years away. Given that and its apparent size of 2.2 by 0.8 arcmin, it is about 175 thousand light years across. It is the result of a collision between two (presumably) spiral galaxies. The galaxies appear to have nearly completed their merger, as the gas-rich remnant contains only one nucleus, but long tails of stars scattered into intergalactic space and moderate starburst activity near the center of the combined galaxy give testament to the collision. Note: NGC 17 and 35 are only a few arcmin apart, and given their apparently common distance may be less than half a million light years apart. If so, they could be gravitationally bound.
HST image of region near spiral galaxy NGC 17, overlaid on a DSS background to fill in missing areas, also showing NGC 35
Above, a 12 arcmin wide DSS image centered on NGC 17, also showing NGC 35
(NGC 17 is actually shown by an overlay of the HST images shown below, which see for credits)
Below, a high-contrast HST view of NGC 17 and its tails (bright to upper left, faint to lower right)
HST mosaic of spiral galaxy NGC 17 and its tails
Below, a more normal view of the brighter tail and core of the galaxy, rotated to show greater detail
(Credit for all versions of the HST image: NASA, ESA, the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration,
and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University), HubbleSite)

HST mosaic of brighter tail and central portion of spiral galaxy NGC 17
Below, a still closer HST view of the central galaxy, with normal orientation (Image Credit as above)
HST mosaic of central portion of spiral galaxy NGC 17
Below, a 12 arcmin wide DSS image centered on NGC 17, overlaid by an HST image of the galaxy
Also shown are NGC 35 and PGC 956278, 958282, and 958866
HST image of region near spiral galaxy NGC 17, overlaid on a DSS background to fill in missing areas, also showing NGC 35

NGC 18
Recorded (Oct 15, 1866) by
Herman Schultz
Looked for but not recognized by several other observers (as noted below)
A magnitude 13.4 and 13.6 double star in Pegasus (RA 00 09 23.1, Dec +27 43 55)
Historical Identification: Per Dreyer, NGC 18 (= GC 5085, Schultz (Nova I), 1860 RA 00 02 11, NPD 63 02.8) is "faint, very small, irregularly round, much brighter middle, h4 19s to west", h4 (= JH 4) being NGC 16 (which see for an image of NGC 18). A note at the end of the NGC indicates the likelihood that the object was not nebulous: "18: GC 5085, nova Schultz. Not seen by Stephan (XIII); does not occur in d'Arrest's nor in Lord Rosse's observations." The position precesses to RA 00 09 23.7, Dec +27 43 58, within 0.1 arcmin of the pair of stars listed above, and NGC 16 is 18 seconds to the west, so the identification is certain.

NGC 19 (= PGC 759)
Discovered (Sep 20, 1885) by
Lewis Swift
A magnitude 13.3 spiral galaxy (type SB(rs)bc?) in Andromeda (RA 00 10 40.9, Dec +32 58 59)
Historical Identification: Per Dreyer, NGC 19 (Swift list II (#4), 1860 RA 00 02 13, NPD 57 55.6) is "most extremely faint, a little extended, 3 very faint stars around". The position precesses to RA 00 09 26.3, Dec +32 51 09, but there is nothing there. However, as noted in the discussion of NGC 6, this is one of several galaxies discovered by Swift on the same night which mostly share an average error of 70 seconds of time too far west and 8' 12" too far south. Applying that correction, Swift's position for his II-4 precesses to RA 00 10 36.8, Dec +32 59 23, less than an arcmin west northwest of the galaxy listed above, and Swift's detailed description of the star field, "in center of 3 very faint stars forming an equilatoral (sic) triangle, two of them double", exactly matches the nearby stars, so the identification is certain.
Note About Frequent Confusion With NGC 21: NGC 21 is almost due north of NGC 19, and Swift's incorrect declination for NGC 21 lies about halfway between them. By an unhappy coincidence, two major catalogs very rapidly put together in the 1970's misidentified the southern galaxy as NGC 21. It was only fairly recently that studies of the original observations of NGC objects showed that it was actually NGC 19. So although almost all modern references have corrected the mistake, a warning about a possible misidentification of NGC 19 as NGC 21 is still appropriate.
Physical Information: Based on a recessional velocity of 4790 km/sec, NGC 19 is about 225 million light years away, in good agreement with redshift-independent distance estimates of 185 to 235 million light years. Given that and its apparent size of 1.15 by 0.55 arcmin, it is about 75 thousand light years across.
SDSS image of spiral galaxy NGC 19
Above, a 12 arcmin wide SDSS image centered on NGC 19
Below, a 1.2 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy NGC 19
Below, a 12 arcmin wide SDSS image centered on NGC 19, showing a number of fainter galaxies,
including PGC 2018395, 2019088, 2019785 and 2022467
SDSS image of region near spiral galaxy NGC 19, also showing numerous PGC objects

NGC 20 (= PGC 679 =
NGC 6)
Discovered (Sep 18, 1857) by R. J. Mitchell (and later listed as NGC 20)
Also observed (Oct 16, 1866) by Herman Schultz (and later listed as NGC 20)
Recorded (Sep 20, 1885) by Lewis Swift (and later listed as NGC 6)
A magnitude 13.1 lenticular galaxy (type E/S0?) in Andromeda (RA 00 09 32.7, Dec +33 18 31)
Historical Identification: Per Dreyer, NGC 20 (= GC 6 = GC 5086, 3rd Lord Rosse, Schultz (Nova II), 1860 RA 00 02 21, NPD 57 28.2) is "faint, 10th magnitude star attached". The position precesses to RA 00 09 34.4, Dec +33 18 34, only 2 seconds of time east of the center of the galaxy listed above, between the galaxy and the 10th magnitude star that lies almost in front of it, so the identification is certain. (For a discussion of the duplicate entry, see NGC 6.)
Discovery Notes: Although Dreyer credits the report of the discovery to William Parsons, 3rd Earl of Rosse, he notes that many of Rosse's nebular discoveries were actually made by his assistants, George Stoney, Bindon Stoney and R. J. Mitchell.
Physical Information: Based on a recessional velocity of 4970 km/sec, NGC 20 is about 230 million light years away. Given that and its apparent size of 1.9 by 1.5 arcmin, it is about 130 thousand light years across.
SDSS image of region near lenticular galaxy NGC 20
Above, a 12 arcmin wide SDSS image centered on NGC 20
Below, a 2.4 arcmin wide SDSS image of the galaxy
SDSS image of lenticular galaxy NGC 20
Below, a 12 arcmin wide SDSS image centered on NGC 20;
also shown are PGC 212477, 2026460 and 2027085
SDSS image of region near lenticular galaxy NGC 20, also showing numerous PGC objects

NGC 21 (=
NGC 29 = PGC 767)
Discovered (Nov 26, 1790) by William Herschel (and later listed as NGC 29)
Also observed (Nov 11, 1827) by John Herschel (and later listed as NGC 29)
Recorded (Sep 20, 1885) by Lewis Swift (and later listed as NGC 21)
A magnitude 12.7 spiral galaxy (type SAB(s)bc?) in Andromeda (RA 00 10 46.9, Dec +33 21 10)
Historical Identification: Per Dreyer, NGC 21 (Swift list II (#5), 1860 RA 00 02 25, NPD 57 34.1) is "extremely faint, small, a little extended". Swift's position precesses to RA 00 09 38.5, Dec +33 12 39, but there is nothing there. However, as noted in the discussion of NGC 6, this is one of several galaxies discovered by Swift on the same night which mostly share an average error of 70 seconds of time too far west and 8' 12" too far south. Applying that correction, Swift's position for his II-5 precesses to RA 00 10 48.9, Dec +33 20 53, on the southeastern rim of the galaxy listed above and the description fits, so the identification is considered certain. The duplicate entry is due to the fact that with such a large error in Swift's position, there was no way for Dreyer to realize that it was an observation of a previously discovered nebula.
Note About Frequent Confusion With NGC 19: NGC 21 is almost due north of NGC 19, and Swift's incorrect declination for NGC 21 lies about halfway between them. By an unhappy coincidence, two major catalogs very rapidly put together in the 1970's misidentified the southern galaxy as NGC 21. It was only fairly recently that studies of the original observations of NGC objects showed that it was actually NGC 19. So although almost all modern references have corrected the mistake, a warning about a possible misidentification of NGC 19 as NGC 21 is still appropriate.
Physical Information: Based on a recessional velocity of 4770 km/sec, NGC 21 is about 220 million light years away, in good agreement with redshift-independent distance estimates of 200 to 270 million light years. Given that and its apparent size of 1.55 by 0.6 arcmin, it is about 100 thousand light years across.
SDSS image of region near spiral galaxy NGC 21
Above, a 12 arcmin wide SDSS image centered on NGC 21
Below, a 1.5 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy NGC 21

NGC 22 (= PGC 690)
Discovered (Oct 2, 1883) by
Édouard Stephan
A magnitude 13.6 spiral galaxy (type Sb?) in Andromeda (RA 00 09 48.2, Dec +27 49 56)
Historical Identification: Per Dreyer, NGC 22 (Stephan list XIII (#1), 1860 RA 00 02 36, NPD 62 56.9) is "very faint, pretty small, round, little brighter middle, mottled but not resolved". The position precesses to RA 00 09 48.9, Dec +27 49 52, within 0.2 arcmin of the center of the galaxy listed above and well within its outline, so the identification is certain.
Discovery Notes: When John Herschel published his "General Catalog", GC 8 was defined as JH 4, and GC 12 was defined as JH 5 and assumed equal to WH IV 15; and since Dreyer published the NGC it has been assumed that GC 12 = GC 8 = NGC 16. However, in 2014 it was suggested that JH 5 and WH IV 15 are not observations of NGC 16, but of some faint star or perhaps even NGC 22. As discussed in the entry for NGC 16 that is almost certainly wrong, so this note serves as a warning to ignore any suggestion that the Herschels had anything to do with the discovery of NGC 22.
Physical Information: Based on a recessional velocity of 8310 km/sec, a straightforward calculation indicates that NGC 22 is about 385 million light years away, in good agreement with redshift-independent distance estimates of 335 to 435 million light years. However, for objects at such distances we should take into account the expansion of the Universe during the time it took their light to reach us. Doing that shows that the galaxy was about 375 million light years away at the time the light by which we see it was emitted, about 380 million years ago (the difference between the two numbers being due to the expansion of the intervening space during the light-travel time). Given that and its apparent size of 1.55 by 0.95 arcmin, the galaxy is about 170 thousand light years across.
SDSS image of region near spiral galaxy NGC 22
Above, a 12 arcmin wide SDSS image centered on NGC 22
Below, a 2.0 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy NGC 22
Below, a 12 arcmin wide SDSS image centered on NGC 22, also showing PGC 212478 and 1820266
SDSS image of region near spiral galaxy NGC 22, also showing several PGC objects

NGC 23 (= PGC 698)
Discovered (Sep 10, 1784) by
William Herschel
A magnitude 12.0 spiral galaxy (type SB(rs)ab?) in Pegasus (RA 00 09 53.4, Dec +25 55 26)
Historical Identification: Per Dreyer, NGC 23 (= GC 9 = WH III 147, 1860 RA 00 02 41, NPD 64 51.0) is "3 small stars plus nebulosity". The position precesses to RA 00 09 53.7, Dec +25 55 46, only 0.3 arcmin north of the center of the galaxy listed above and well within its outline, so the identification is certain.
Physical Information: Based on a recessional velocity of 4565 km/sec, NGC 23 is about 210 million light years distant, in good agreement with redshift-independent distance estimates of 175 to 210 million light years. Given that and its apparent size of 3.35 by 1.8 arcmin, it is about 205 thousand light years across. NGC 23 is listed as a starburst galaxy.
SDSS image of region near spiral galaxy NGC 23
Above, a 12 arcmin wide SDSS image centered on NGC 23
Below, a 3.6 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy NGC 23
Below, a 14 arcsec wide HST image of the active core of the galaxy (Image Credit Hubble Legacy Archive)
HST image of active core of spiral galaxy NGC 23
Below, a 12 arcmin wide SDSS image centered on NGC 23, also showing PGC 1754508 and 1757813
A distant cluster of galaxies lies to the southeast, but its faint members are not listed in most catalogs
SDSS image of region near spiral galaxy NGC 23

NGC 24 (= PGC 701)
Discovered (Oct 27, 1785) by
William Herschel
Also observed (Sep 12, 1836) by John Herschel
A magnitude 11.6 spiral galaxy (type SA(s)c?) in Sculptor (RA 00 09 56.3, Dec -24 57 48)
Historical Identification: Per Dreyer, NGC 24 (= GC 10 = JH 2308 = WH III 461, 1860 RA 00 02 47, NPD 115 45.0) is "very faint, considerably large, much extended, gradually brighter middle". The position precesses to RA 00 09 54.8, Dec -24 58 14, only 0.5 arcmin southwest of the center of the galaxy listed above and well within its outline, so the identification is certain.
Physical Information: Based on a recessional velocity of 555 km/sec, NGC 24 is about 25 million light years away, but for such distances peculiar (non-Hubble-redshift) velocities can significantly affect the accuracy of the estimate. Unfortunately, redshift-independent estimates range from as little as 3 million to as much as 35 million light years, inspiring even less confidence. However, the galaxy's apparent size of about 5.8 by 1.3 arcmin makes most sense if its distance is in the 25 million light year range, in which case it would be about 40 thousand light years across. It has been suggested that NGC 24 and 45 are a pair, as they have similar recessional velocities and if at similar distances their two degree separation corresponds to less than a million light years. The latter galaxy is more certainly about 25 million light years away, so if they really are a pair it would confirm the estimate made in this entry; but both galaxies' distances are sufficiently uncertain that the suggestion that they are a pair cannot inspire much confidence.
DSS image of region near spiral galaxy NGC 24
Above, a 12 arcmin wide DSS image centered on NGC 24
Below, a 6 arcmin wide image of the galaxy (Image Credit & © Carnegie-Irvine Survey; used by permission)
Carnegie-Irvine Survey image of spiral galaxy NGC 24
Below, a 1.6 arcmin wide image of the central part of the galaxy (Image Credit Hubble Legacy Archive)
HST false-color image of the central part of spiral galaxy NGC 24
Below, a 12 arcmin wide DSS image centered on NGC 24, also showing PGC 783199, 783608 and 785296
DSS image of region near spiral galaxy NGC 24, also showing various PGC objects
Below, a 2 degree wide DSS image centered between possible companions NGC 24 and 45
(The image is centered at RA 00 00 12.0, Dec -24 06 00)
DSS image of region between NGC 24 and NGC 45

NGC 25 (= PGC 706)
Discovered (Oct 28, 1834) by
John Herschel
A magnitude 13.0 lenticular galaxy (type E/SB0? pec) in Phoenix (RA 00 09 59.3, Dec -57 01 15)
Historical Identification: Per Dreyer, NGC 25 (= GC 11 = JH 2309, 1860 RA 00 02 57, NPD 147 48.2) is "very faint, small, round". The position precesses to RA 00 09 59.1, Dec -57 01 26, within 0.2 arcmin of the center of the galaxy listed above and well within its outline, so the identification is certain.
Physical Information: Based on a recessional velocity of 9465 km/sec, a straightforward calculation indicates that NGC 25 is about 440 million light years away. However, for objects at such distances we should take into account the expansion of the Universe during the time it took their light to reach us. Doing that shows that the galaxy was about 425 million light years away at the time the light by which we see it was emitted, about 430 million years ago (the difference between the two numbers being due to the expansion of the intervening space during the light-travel time). Given that and its apparent size of 1.9 by 1.2 arcmin, it is about 235 thousand light years across. The galaxy is the brightest member of Abell 2731, a rich cluster of galaxies with an average recessional velocity of 9350 km/sec and an apparent size of 35 arcmin (corresponding to a physical diameter for the cluster of more than 4 million light years).
DSS image of region near lenticular galaxy NGC 25, also showing NGC 28 and NGC 31
Above, a 12 arcmin wide DSS image centered on NGC 25, also showing NGC 28 and 31
Below, a 2.4 arcmin wide DSS image of the galaxy
DSS image of lenticular galaxy NGC 25
Below, a 12 arcmin wide DSS image centered on NGC 25, also showing NGC 28 and 31
Also shown are sixteen PGC objects
DSS image of region near lenticular galaxy NGC 25, also showing NGC 28 and NGC 31 and sixteen labeled PGC objects
Below, a 6 arcmin wide DSS image of the region between NGC 25 and NGC 31
Also shown are NGC 28 and PGC 394783, 394784, 394941, 394997, 395139 and 395226
DSS image of region between NGC 25 and NGC 31, also showing NGC 28
Below, a 6 arcmin wide DSS image showing objects to the southeast of NGC 25:
Galaxies labeled are PGC 735, 128415, 393982, 394013, 394155, 394279, 394289 and 394344
DSS image of the region to the southeast of lenticular galaxy NGC 25

NGC 26 (= PGC 732)
Discovered (Sep 14, 1865) by
Heinrich d'Arrest
A magnitude 12.9 spiral galaxy (type SA(rs)ab?) in Pegasus (RA 00 10 25.9, Dec +25 49 55)
Historical Identification: Per Dreyer, NGC 26 (= GC 5087, d'Arrest, 1860 RA 00 03 14, NPD 64 56.2) is "very faint, pretty large, round, 2 faint stars to the north". The position precesses to RA 00 10 26.9, Dec +25 50 33, about 0.7 arcmin north northeast of the center of the galaxy listed above, near its northern edge, and there are two faint stars just north of it, so the identification is certain.
Physical Information: Based on a recessional velocity of 4590 km/sec, NGC 26 is about 215 million light years away, in good agreement with redshift-independent distance estimates of 185 to 260 million light years. Given that and its apparent size of 2.4 by 1.3 arcmin, it is about 105 thousand light years across.
SDSS image of region near spiral galaxy NGC 26
Above, a 12 arcmin wide SDSS image centered on NGC 26
Below, a 2.8 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy NGC 26

NGC 27 (= PGC 742)
Discovered (Aug 3, 1884) by
Lewis Swift
A magnitude 13.5 spiral galaxy (type Sbc?) in Andromeda (RA 00 10 32.8, Dec +28 59 46)
Historical Identification: Per Dreyer, NGC 27 (Swift list I (#1), 1860 RA 00 03 15, NPD 61 47.3) is "extremely faint, very small, extended, bright star near". The position precesses to RA 00 10 28.3, Dec +28 59 27, only an arcmin southwest of the galaxy listed above, and less than half an arcmin from its apparent companion, PGC 731. The bright star directly below PGC 742 makes the identification of NGC 27 with one of the two galaxies certain, and although Swift's position is closer to PGC 731 than PGC 742, the two magnitude difference in their brightness makes it certain that what Swift observed was the brighter galaxy.
Observational Note: Although the modern photographs below make it seem like Swift could just as easily have seen both galaxies as only the brighter one, the fact that galaxies are much fainter as visual objects than stars makes it extremely unlikely that he could have seen the fainter one. To show how difficult (or impossible) it would have been for Swift to see PGC 731, the last image for this entry is a simulation of the 33 arcmin field of view used by him, more nearly as seen visually than in a photograph. But even though Swift almost certainly could not see the fainter galaxy, since it is so obvious in modern photographs it is discussed immediately following this entry.
Physical Information: Based on a recessional velocity of 7035 km/sec, NGC 27 is about 325 million light years away, in good agreement with redshift-independent distance estimates of 270 to 320 million light years. However, for objects at such distances we should take into account the expansion of the Universe during the time it took their light to reach us. Doing that shows that the galaxy was less than 320 million light years away at the time the light by which we see it was emitted, more than 320 million years ago (the slight difference between the two numbers being due to the expansion of the intervening space during the light-travel time). Given that and its apparent size of 1.15 by 0.5 arcmin, it is about 105 thousand light years across. (NED also lists a second recessional velocity measurement of 7850 km/sec, but that is undoubtedly a misassigned value for PGC 731, and a good example of why it is necessary to be careful in identifying galaxies by one designation or another.) Although NGC 27 and PGC 731 appear to be close to each other, the fainter galaxy is probably 40 million light years further away, making them most likely merely optical companions.
SDSS image of region near spiral galaxy NGC 27
Above, a 12 arcmin wide SDSS image centered on NGC 27, also showing PGC 731
Below, a 1.2 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy NGC 27
Below, a 33 arcmin wide SDSS image simulating the appearance of Swift's field of view
NGC 27 is the faint object in the center of the image, just above a "bright" star
SDSS simulation of Swift's view of the region near spiral galaxy NGC 27

PGC 731
Not an NGC object but listed here since discussed in the entry for NGC 27
A magnitude 15.5(?) spiral galaxy (type Sc?) in
Andromeda (RA 00 10 26.4, Dec +28 59 16)
Historical Identification: As discussed in the entry for NGC 27, Swift could not have seen PGC 731, despite its reasonably impressive appearance in modern photographs. So it is discussed here only because it is so obvious in such photographs.
Physical Information: Based on a recessional velocity of 7850 km/sec, PGC 731 is about 365 million light years away, in good agreement with redshift-independent distance estimates of 340 to 500 million light years. However, for objects at such distances we should take into account the expansion of the Universe during the time it took their light to reach us. Doing that shows that the galaxy was about 355 million light years away at the time the light by which we see it was emitted, about 360 million years ago (the difference between the two numbers being due to the expansion of the intervening space during the light-travel time). Given that and its apparent size of 1.75 by 0.2 arcmin, it is about 180 thousand light years across. Although NGC 27 and PGC 731 appear to be close to each other, the fainter galaxy is probably 40 million light years further away, making them most likely merely optical companions.
SDSS image of spiral galaxy PGC 731
Above, a 2.0 arcmin wide SDSS image of PGC 731; for a wider view, see NGC 27

NGC 28 (= PGC 730 = PGC 395160)
Discovered (Oct 28, 1834) by
John Herschel
A magnitude 13.8 elliptical galaxy (type E0?) in Phoenix (RA 00 10 25.2, Dec -56 59 21)
Historical Identification: Per Dreyer, NGC 28 (= GC 13 = JH 2310, 1860 RA 00 03 25, NPD 147 46.4) is "extremely faint, the preceding (western) of 2", the other being NGC 31. The position precesses to RA 00 10 26.5, Dec -56 59 38, which is 0.4 arcmin southeast of the center of the galaxy listed above and within its outer glow, and it does precede NGC 31 (which lies just to its east), so the identification is certain. However, as noted by Corwin, at one time some catalogs misidentified NGC 28 as NGC 31, and vice-versa; so the reader may still see their PGC designations reversed in some places.
Physical Information: Based on a recessional velocity of 9595 km/sec, a straightforward calculation indicates that NGC 28 is about 445 million light years away. However, for objects at such distances we should take into account the expansion of the Universe during the time it took their light to reach us. Doing that shows that the galaxy was about 430 million light years away at the time the light by which we see it was emitted, a little over 435 million years ago (the difference between the two numbers being due to the expansion of the intervening space during the light-travel time). Given that and its apparent size of 0.9 by 0.9 arcmin, it is about 115 thousand light years across. Unlike nearby NGC 25, which is listed as a member of Abell 2371, NGC 28 is not listed as such, and could be slightly behind the cluster. But the difference in its recessional velocity is well within the range of peculiar (non-Hubble-expansion) velocities for such clusters, so odds are that it is also a member of the cluster. Regardless of its association with the cluster (or not), it and NGC 31's essentially identical recessional velocities suggest that they may be physical companions.
DSS image of elliptical galaxy NGC 28
Above, a 1.5 arcmin wide DSS image of NGC 28; see NGC 31 for a wide-field image

NGC 29 (=
NGC 21 = PGC 767)
Discovered (Nov 26, 1790) by William Herschel (and later listed as NGC 29)
Also observed (Nov 11, 1827) by John Herschel (and later listed as NGC 29)
Recorded (Sep 20, 1885) by Lewis Swift (and later listed as NGC 21)
A magnitude 12.7 spiral galaxy (type SAB(s)bc?) in Andromeda (RA 00 10 46.9, Dec +33 21 10)
Historical Identification: Per Dreyer, NGC 29 (= GC 14 = JH 6 = WH II 853, 1860 RA 00 03 32, NPD 57 25.6) is "pretty bright, pretty large, extended 0º". The position precesses to RA 00 10 46.1, Dec +33 21 09, within 0.2 arcmin of the center of the galaxy listed above and well within its outline, so the identification is certain. The double listing is due to Swift's position being so poor that there was no reason for Dreyer to suspect that it was a re-observation of Herschel's object. Because of the resulting confusion, the object is sometimes called NGC 29, and sometimes NGC 21 (which see for anything else).

NGC 30
Recorded (Oct 30, 1864) by
Albert Marth
A magnitude 14.8 and 15.0 double star in Pegasus (RA 00 10 50.7, Dec +21 58 38)
Historical Identification: Per Dreyer, NGC 30 (= GC 5088, Marth #4, 1860 RA 00 03 38, NPD 68 49) is "a nebulous star 13th magnitude". The position precesses to RA 00 10 50.6, Dec +21 57 45, an arcmin south of the pair listed above. Per Corwin, there are no galaxies within 10 arcmin, and the close double would appear nebulous under less than perfect seeing, so the description confirms the identification.
SDSS image of region near the double star listed as NGC 30
Above, a 12 arcmin wide SDSS image centered on NGC 30

NGC 31 (= PGC 751)
Discovered (Oct 28, 1834) by
John Herschel
A magnitude 13.9 spiral galaxy (type SAB(rs)cd?) in Phoenix (RA 00 10 38.4, Dec -56 59 11)
Historical Identification: Per Dreyer, NGC 31 (= GC 15 = JH 2311, 1860 RA 00 03 39, NPD 147 46.4) is "most extremely faint, small, round, following (eastern) of 2", the other being NGC 28. The position precesses to RA 00 10 40.2, Dec -56 59 38, which is, as for NGC 28, southeast of the center of the galaxy listed above (in this case, about 0.6 arcmin), but still near the outline of the galaxy. It definitely "follows" NGC 28, which lies just to its west, so the identification is certain. However, as noted by Corwin, at one time some catalogs misidentified NGC 28 as NGC 31, and vice-versa; so the reader may still see their PGC designations reversed in some places. (It is interesting to note the difference between interpretations based on modern photographic images, and the direct observational techniques of the 19th century. Nowadays the ability to photograph the faint outer regions of the galaxy makes NGC 31 appear much larger than and just as bright as NGC 28; but Herschel saw only the bright core of NGC 31, making it appear to be substantially fainter.)
Physical Information: Based on a recessional velocity of 9600 km/sec, a straightforward calculation indicates that NGC 31 is about 445 million light years away. However, for objects at such distances we should take into account the expansion of the Universe during the time it took their light to reach us. Doing that shows that the galaxy was about 430 million light years away at the time the light by which we see it was emitted, a little over 435 million years ago (the difference between the two numbers being due to the expansion of the intervening space during the light-travel time). Given that and its apparent size of 1.2 by 0.6 arcmin, it is about 150 thousand light years across. Like nearby NGC 28, it may be an unlisted member of Abell 2731, and since the two galaxies have nearly identical recessional velocities, regardless of their association with the cluster (or not), they may be physical companions.
DSS image of region near spiral galaxy NGC 31, also showing NGC 25, NGC 28 and NGC 37
Above, a 12 arcmin wide DSS image centered on NGC 31, also showing NGC 25, 28 and 37
Below, a 1.5 arcmin wide DSS image of the galaxy
DSS image of spiral galaxy NGC 31
Below, a 12 arcmin wide DSS image centered near the galaxy, also showing NGC 25, 28 and 37
Also shown are a dozen PGC objects (see NGC 25 for more detailed images)
DSS image of region near spiral galaxy NGC 31, also showing NGC 25, NGC 28 and NGC 37, and a dozen PGC objects

NGC 32
Recorded (Oct 10, 1861) by
Julius Schmidt
A magnitude 13.5 star in Pegasus (RA 00 10 53.6, Dec +18 47 46)
Historical Identification: Per Dreyer, NGC 32 (= GC 16, J Schmidt, 1860 RA 00 03 42, NPD 71 59.0) is "faint (Auwers 1)". The listed position precesses to RA 00 10 54.3, Dec +18 47 45, which is only 0.3 arcmin northeast of the star listed above, and as noted by Corwin, Auwers' record of Schmidt's original observation precesses to RA 00 10 54.0, Dec +18 47 45, within 3 arcsec of the star, so the identification is certain.
Discovery Notes: Dreyer's reference to Arthur von Auwers does not mean that Auwers observed this object. A catalog of all known nebulae published by Auwers in 1862 was one of the sources for John Herschel's GC, which was the basis for the NGC. In this case "(Auwers 1)" means that in Herschel's entry for GC 16 he cites #1 in Auwers' table of nebulae discovered by various observers (mostly after 1845) as the source for his information about Schmidt's discovery (just as I used Auwers' catalog to obtain the position stated in the historical discussion).
SDSS image of region near the star listed as NGC 32
Above, a 12 arcmin wide SDSS image centered on NGC 32; also shown are PGC 1570691 and 1573666

NGC 33
Recorded (Sep 9, 1864) by
Albert Marth
A magnitude 15.5 and 15.8 double star in Pisces (RA 00 10 56.6, Dec +03 40 33)
Historical Identification: Per Dreyer, NGC 33 (= GC 5089, Marth #5, 1860 RA 00 03 45, NPD 87 06) is "extremely faint, very small, or nebulous star". The position precesses to RA 00 10 55.6, Dec +03 40 45, only 0.3 arcmin northwest of the pair of stars listed above, and there is nothing else nearby. As in the case of NGC 30, such a double could have appeared nebulous under normal conditions, so the identification is certain.
SDSS image of region near the double star listed as NGC 33
Above, a 12 arcmin wide SDSS image centered on NGC 33

NGC 34 (=
NGC 17 = PGC 781)
Discovered (Nov 21, 1886) by Lewis Swift (and later listed as NGC 34)
Also discovered (1886) by Frank Muller (and later listed as NGC 17)
Also observed (Jul 1, 1899 to Jun 30, 1900) by Herbert Howe (proving NGC 17 = NGC 34)
A magnitude 14.4 spiral galaxy (type S? pec) in Cetus (RA 00 11 06.5, Dec -12 06 27)
Historical Identification: Per Dreyer, NGC 34 (Swift list VI (#1), 1860 RA 00 03 53, NPD 102 53.2) is "pretty faint, small, round, 2 stars nearby". The position precesses to RA 00 11 01.9, Dec -12 06 27, about 5 seconds of time west of the galaxy listed above, but there is nothing comparable nearby and the double star west of the galaxy makes the identification certain. The double listing is due to the fact that Muller's and Swift's positions differ by nearly half a degree (being 5 seconds off for Swift and 2 minutes for Muller), so Dreyer had no reason to suspect the identity of the two nebulae. However, on the basis of the nearby stars mentioned by both observers, Howe discovered the equality of the two observations in 1899/1900, causing Dreyer to state "NGC 17 = 34 (Howe)" in the corrections for NGC objects published in the Second Index Catalog; so the duplicate entry has been known about for more than a century.
Physical Information: Although Swift had the far better position, tradition assigns the numerically earlier designation to duplicate entries, so see NGC 17 for anything else.

NGC 35 (= PGC 784)
Discovered (Nov 21, 1886) by
Lewis Swift
Also discovered (1886) by Frank Muller
A magnitude 14.1 spiral galaxy (type Sbc? pec) in Cetus (RA 00 11 10.5, Dec -12 01 15)
Historical Identification: Per Dreyer, NGC 35 (Swift list VI (#2), Muller list II (#277), 1860 RA 00 04 03, NPD 102 47.2) is "most extremely faint, pretty small, round". The position precesses to RA 00 11 11.9, Dec -12 00 27, less than an arcmin northeast of the galaxy listed above and there is nothing comparable nearby, so the identification is certain.
Physical Information: Based on a recessional velocity of 5965 km/sec, NGC 35 is about 275 million light years away. Given that and its apparent size of 0.6 by 0.4 arcmin, it is about 50 thousand light years across. Note: NGC 35 and 17 are only a few arcmin apart, and given their apparently common distance, may be less than half a million light years apart. If so, they would be gravitationally bound, and their distorted appearance may involve gravitational interaction.
DSS image of region near spiral galaxy NGC 35, also showing NGC 17
Above, a 12 arcmin wide DSS image centered on NGC 35
Below, a 0.8 arcmin wide DSS image of NGC 35
DSS image of spiral galaxy NGC 35
Below, a 33 arcsec wide HST image of star-forming regions in the galaxy (Image Credit Hubble Legacy Archive)
'Raw' HST image of star-forming regions in spiral galaxy NGC 35
Below, a 12 arcmin wide DSS image centered on NGC 35
Also shown are NGC 17 and PGC 957826, 958282 and 958866
DSS image of region near spiral galaxy NGC 35, also showing NGC 17 and several PGC objects

NGC 36 (= PGC 798)
Discovered (Oct 25, 1785) by
William Herschel
Also observed (Oct 5, 1864) by Heinrich d'Arrest
A magnitude 13.3 spiral galaxy (type SAB(rs)b?) in Pisces (RA 00 11 22.3, Dec +06 23 22)
Historical Identification: Per Dreyer, NGC 36 (= GC 19 = WH III 456, d'Arrest, 1860 RA 00 04 11, NPD 84 24.2) is "very faint, pretty small, irregular figure". The position precesses to RA 00 11 21.9, Dec +06 22 33, only 0.8 arcmin south of the center of the galaxy listed above and still within its outline, so the identification is certain.
Discovery Notes: In Dreyer's 1877 Supplement to Sir John Herschel's "General Catalog of Nebulae and Clusters of Stars" he states that d'Arrest's measurements place the nebula 1 minute of time to the west of the GC position, and the position in the NGC agrees with that correction.
Physical Information: Based on a recessional velocity of 6030 km/sec, NGC 36 is about 280 million light years away, in reasonable agreement with redshift-independent distance estimates of 220 to 270 million light years. Given that and its apparent size of 3.2 by 1.3 arcmin, it is about 270 thousand light years across. Note: The distance of its apparently close neighbor (PGC 797) is unknown, so whether it is a small companion of NGC 36 or (as is far more likely) a far more distant galaxy is also unknown
SDSS image of region near spiral galaxy NGC 36
Above, a 12 arcmin wide SDSS image centered on NGC 36
Below, a 3.3 arcmin wide SDSS image of NGC 36 and PGC 797
SDSS image of spiral galaxy NGC 36 and its apparent but probably not physical companion, PGC 797
Below, a 12 arcmin wide SDSS image centered on NGC 36, also showing PGC 797 and PGC 212482
SDSS image of region near spiral galaxy NGC 36, also showing some PGC objects

NGC 37 (= PGC 801 = PGC 395521)
Discovered (Oct 2, 1836) by
John Herschel
A magnitude 13.7 spiral galaxy (type (R')SAB0(s)a?) in Phoenix (RA 00 11 22.9, Dec -56 57 26)
Historical Identification: Per Dreyer, NGC 37 (= GC 17 = JH 2312, 1860 RA 00 04 22, NPD 147 43.8) is "extremely faint, small, round". The position precesses to RA 00 11 22.3, Dec -56 57 03, only 0.4 arcmin north northwest of the center of the galaxy listed above and within its outline, so the identification is certain.
Physical Information: Based on a recessional velocity of 9775 km/sec, a straightforward calculation indicates that NGC 37 is about 455 million light years away. However, for objects at such distances we should take into account the expansion of the Universe during the time it took their light to reach us. Doing that shows that the galaxy was about 440 million light years away at the time the light by which we see it was emitted, a little over 445 million years ago (the difference between the two numbers being due to the expansion of the intervening space during the light-travel time). Given that and its apparent size of 1.35 by 0.7 arcmin, the galaxy is about 175 thousand light years across.
DSS image of region near spiral galaxy NGC 37, also showing NGC 31
Above, a 12 arcmin wide DSS image centered on NGC 37, also showing NGC 31
Below, a 1.5 arcmin wide DSS image of NGC 37, also showing PGC 95382
DSS image of spiral galaxy NGC 37
Below, a 12 arcmin wide DSS image centered on NGC 37, also showing NGC 31
Also shown are PGC 95382, 128413, 128414, 395650, 395783, 396047, 396284 and 396380
DSS image of region near spiral galaxy NGC 37, also showing NGC 31 and a number of PGC objects

NGC 38 (= PGC 818)
Discovered (Oct 25, 1881) by
Édouard Stephan
A magnitude 13.3 spiral galaxy (type (R)SAa?) in Pisces (RA 00 11 47.0, Dec -05 35 11)
Historical Identification: Per Dreyer, NGC 38 (Stephan list XII (#3), 1860 RA 00 04 38, NPD 96 22.0) is "faint, small, round, much brighter middle". The position precesses to RA 00 11 47.6, Dec -05 35 15, only 0.2 arcmin from the center of the galaxy listed above and well within its outline, so the identification is certain.
Physical Information: Based on a recessional velocity of 8035 km/sec, a straightforward calculation indicates that NGC 38 is about 375 million light years away. However, for objects at such distances we should take into account the expansion of the Universe during the time it took their light to reach us. Doing that shows that the galaxy was less than 365 million light years away at the time the light by which we see it was emitted, a little over 365 million years ago (the slight difference between the two numbers being due to the expansion of the intervening space during the light-travel time). Given that and its apparent size of 1.2 by 1.2 arcmin, the galaxy is about 125 thousand light years across.
SDSS image of region near spiral galaxy NGC 38
Above, a 12 arcmin wide SDSS image centered on NGC 38
Below, a 1.5 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy NGC 38
Below, a 12 arcmin wide SDSS image centered on NGC 38
Also shown are PGC 1042100, 1042151, 1042790 and 1043800
SDSS image of region near spiral galaxy NGC 38, also showing several PGC objects

NGC 39 (= PGC 852)
Discovered (Nov 2, 1790) by
William Herschel
Also observed (Nov 16, 1827) by John Herschel
A magnitude 13.5 spiral galaxy (type SA(rs)c?) in Andromeda (RA 00 12 18.9, Dec +31 03 40)
Historical Identification: Per Dreyer, NGC 39 (= GC 18 = JH 7 = WH III 861, 1860 RA 00 05 04, NPD 59 41.4) is "very faint, pretty small, round". The position precesses to RA 00 12 18.5, Dec +31 05 21, almost 2 arcmin north of the galaxy listed above, but there is nothing else within 10 arcmin, so the identification is certain.
Physical Information: Based on a recessional velocity of 4855 km/sec, NGC 39 is about 225 million light years away. Given that and its apparent size of 1.2 by 1.05 arcmin, it is about 80 thousand light years across.
SDSS image of region near spiral galaxy NGC 39
Above, a 12 arcmin wide SDSS image centered on NGC 39
Below, a 1.5 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy NGC 39
Below, a 12 arcmin wide SDSS image centered on NGC 39, also showing PGC 1927012 and 1927069
SDSS image of region near spiral galaxy NGC 39, also showing some PGC objects

NGC 40, the Bow-Tie Nebula (= PGC 2923327)
Discovered (Nov 25, 1788) by
William Herschel
Also observed (Nov 20, 1829) by John Herschel
A magnitude 12.3 planetary nebula in Cepheus (RA 00 13 01.0, Dec +72 31 19)
Historical Identification: Per Dreyer, NGC 40 (= GC 20 = JH 8 = WH IV 58, 1860 RA 00 05 27, NPD 18 15.4) is "faint, very small, round, very suddenly much brighter middle, 12th magnitude star to the southwest". The position precesses to RA 00 13 00.7, Dec +72 31 20, dead center on the nebula listed above, and there is an appropriate star to the southwest, so the identification is certain.
Physical Information: NGC 40 is the result of a sunlike star ejecting material into space, during its transformation from a red giant (or dying star) to a white dwarf (or "dead" star). The central star in the nebula is a recently formed, very hot (about 100 thousand Fahrenheit degrees) proto-white dwarf. The nebula is about 3500 light years away, and 1 light year across. Most of the radiation from the nebula is given off by clouds of gas heated to about 20 thousand (Fahrenheit) degrees by the light of the star, but there are also regions which have been heated to millions of degrees by compressive forces generated by the collision of interstellar and previously ejected gases with a 2 million mile per hour stellar wind emitted by the dying star. Over a period of 30 or 40 thousand years, the radiation and stellar wind from the white dwarf will fade away, and the nebula will disappear from view. This is the blink of an eye in astronomical terms, but about one planetary nebula is formed in our galaxy each year, so at any given time there are tens of thousands of them scattered across the galaxy. NGC 40 is sometimes referred to as the "Bow-Tie Nebula" due to the faint extensions to the northwest and south, as shown in the wide-field images.
Misti Mountain Observatory image of region near planetary nebula NGC 40 overlaid on a DSS background to fill in missing areas
Above, a 12 arcmin DSS image centered on NGC 40, using a high-quality overlay of the nebula itself
(Credit & © for overlay image: Jim Misti, Misti Mountain Observatory; used by permission)
Below, a 5 arcmin wide DSS image of the nebula overexposed to show the "bow-tie"
DSS image of 'bow-tie' for planetary nebula NGC 40
Below, 1.9 arcmin wide image of NGC 40 (Credit & ©: Jim Misti, Misti Mountain Observatory, used by permission)
Misti Mountain Observatory image of planetary nebula NGC 40
Below, an X-ray image (in blue) of collisionally heated regions superimposed on a visible-light image
(Credits: X-ray: NASA/CXC/RIT/J.Kastner & R.Montez.; Optical: NSF/AURA/NOAO/WIYN, Chandra)
Visible and X-ray composite image of planetary nebula NGC 40

NGC 41 (= PGC 865)
Discovered (Oct 30, 1864) by
Albert Marth
A magnitude 13.7 spiral galaxy (type Sd?) in Pegasus (RA 00 12 48.0, Dec +22 01 24)
Historical Identification: Per Dreyer, NGC 41 (= GC 5090, Marth #6, 1860 RA 00 05 33, NPD 68 46) is "pretty faint, small, little extended, gradually brighter middle". The position precesses to RA 00 12 46.3, Dec +22 00 44, only 0.8 arcmin southwest of the galaxy listed above and there is nothing else nearby, so the identification is certain.
Physical Information: Based on a recessional velocity of 5950 km/sec, NGC 41 is about 275 million light years away, in reasonable agreement with redshift-independent distance estimates of 245 to 270 million light years. Given that and its apparent size of 0.9 by 0.5 arcmin, it is about 70 thousand light years across. NGC 41 and 42 are only a few arcmin apart and appear to be at the same distance, so they may be physical companions.
SDSS image of region near spiral galaxy NGC 41, also showing NGC 42
Above, a 12 arcmin wide SDSS image centered on NGC 41, also showing NGC 42
Below, a 1.0 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy NGC 41
Below, a 12 arcmin wide SDSS image centered on NGC 41
Also shown are NGC 42 and PGC 855, 212483 and 1660999
SDSS image of region near spiral galaxy NGC 41, also showing NGC 42 and several PGC objects

NGC 42 (= PGC 867)
Discovered (Oct 30, 1864) by
Albert Marth
A magnitude 13.8 lenticular galaxy (type E/S0?) in Pegasus (RA 00 12 56.3, Dec +22 06 01)
Historical Identification: Per Dreyer, NGC 42 (= GC 5091, Marth #7, 1860 RA 00 05 42, NPD 68 41) is "pretty faint, small, a little extended, gradually brighter middle". The position precesses to RA 00 12 55.3, Dec +22 05 44, only 0.4 arcmin southwest of the galaxy listed above and there is nothing comparable nearby, so the identification is certain.
Physical Information: Based on a recessional velocity of 5980 km/sec, NGC 42 is about 280 million light years away. Given that and its apparent size of 1.15 by 0.5 arcmin, it is about 95 thousand light years across. NGC 42 and 41 are only a few arcmin apart and appear to be at about the same distance, so they may be physical companions. However, PGC 212483 is a much closer dwarf galaxy and has no relationship to either.
SDSS image of region near lenticular galaxy NGC 42, also showing NGC 41
Above, a 12 arcmin wide SDSS image centered on NGC 42, also showing NGC 41
Below, a 1.2 arcmin wide SDSS image of NGC 42
SDSS image of lenticular galaxy NGC 42
Below, a 12 arcmin wide SDSS image centered on NGC 42
Also shown are NGC 41 and PGC 212483 and 1665065
SDSS image of region near lenticular galaxy NGC 42, also showing NGC 41 and some PGC objects

NGC 43 (= PGC 875)
Discovered (Nov 11, 1827) by
John Herschel
A magnitude 12.6 lenticular galaxy (type SAB0?) in Andromeda (RA 00 13 00.8, Dec +30 54 55)
Historical Identification: Per Dreyer, NGC 43 (= GC 21 = JH 9, 1860 RA 00 05 46, NPD 59 49.8) is "extremely faint, 12th magnitude star 45 arcsec to northwest". The position precesses to RA 00 13 00.8, Dec +30 56 56, about 2 arcmin north of the galaxy listed above, but there is no comparable object nearby and the star to its northwest confirms the identification, so it is certain.
Discovery Notes: A note at the end of the NGC adds: "43: (John Herschel's) h9. (Herman) Schultz says: 'An extremely faint nebula suspected northwest between star DM30° 20 and a faint star to the north.'" This suggests that Dreyer thought Schultz' observation might have been of NGC 43; but that is to the west southwest, not the northwest, and there is nothing of interest to the northwest of DM30° 20, so whether Schultz observed this object or anything at all is uncertain at best.
Physical Information: Based on a recessional velocity of 4785 km/sec, NGC 43 is about 225 million light years distant. Given that and its apparent size of 1.4 by 1.3 arcmin, it is about 90 thousand light years across.
SDSS image of region near lenticular galaxy NGC 43
Above, a 12 arcmin wide SDSS image centered on NGC 43
Below, a 1.8 arcmin wide SDSS image of NGC 43
SDSS image of lenticular galaxy NGC 43
Below, the 12 arcmin wide SDSS image showing several fainter galaxies, including PGC 1924587
SDSS image of region near lenticular galaxy NGC 43, showing labels for several fainter galaxies

NGC 44
Recorded (Nov 22, 1827) by
John Herschel
A magnitude 14.6 double star in Andromeda (RA 00 13 13.4, Dec +31 17 11)
Historical Identification: Per Dreyer, NGC 44 (= GC 22 = JH 10, 1860 RA 00 05 59, NPD 59 29.3) is "extremely faint, very small" (per Corwin, Herschel adds "not to be seen but in the clearest night", indicating that the object was at the limit of observation). The position precesses to RA 00 13 14.0, Dec +31 17 26, only 15 arcsec northeast of the pair of stars listed above, and since the description is apt, the identification is certain.
SDSS image of region near the double star listed as NGC 44, also showing a PGC object
Above, a 12 arcmin wide region centered on NGC 44, also showing PGC 1943513

NGC 45 (= PGC 930)
Discovered (Nov 11, 1835) by
John Herschel
Also observed (Jul 1, 1899 to Jun 30, 1900) by Herbert Howe
A magnitude 10.6 spiral galaxy (type SA(s)dm?) in Cetus (RA 00 14 04.0, Dec -23 10 52)
Historical Identification: Per Dreyer, NGC 45 (= GC 23 = JH 2313, 1860 RA 00 06 48, NPD 113 57.2) is "extremely faint, large, very gradually very little brighter middle, large star in contact following (to the east)". The position precesses to RA 00 13 54.6, Dec -23 10 28, about 9 seconds of time west of the center of the galaxy listed above, but well within its outline, so the identification is certain.
Discovery Notes: The diffuse nature of the galaxy must have presented problems in determining its position, as the brightest star in the field, 7th magnitude HD 941, is to the southwest, not the east; but since Herschel's position for the galaxy was too far to the west, the star would have seemed further east in comparison. And although apparently not noted by anyone at the time, Howe stated that the NGC right ascension was 10 seconds of time too small, so his position was essentially dead-center on the galaxy.
Physical Information: Based on a recessional velocity of 465 km/sec, NGC 45 is only 22 million light years away, at the lower end of redshift-independent distance estimates of 20 to 40 million light years. Given that and its apparent size of 8.6 by 5.5 arcmin, it is about 50 thousand light years across. It has been suggested NGC 45 and 24 (which see for a view of the region between the galaxies) are a pair, as they are not far apart (about two degrees, which would correspond to less than a million light years at their probable distance), and have similar recessional velocities. The latter galaxy is probably 20 to 30 million light years away, so if they really are a pair, it would support the distance estimate in this entry; but both galaxies' distances are very uncertain, so the presumption that they are a pair cannot be viewed with confidence.
Image of region near spiral NGC 45 uploaded to Wikisky by Jim Riffle
Above, a 12 arcmin wide image centered on NGC 45 (Image credit: Uploaded to Wikisky by Jim Riffle)
Below, an 8 arcmin wide image of the galaxy (Image Credit & © Carnegie-Irvine Survey; used by permission)
Carnegie-Irvine Survey image of spiral galaxy NGC 45
Below, an 8 by 9.5 arcmin wide image of NGC 45, also showing several fainter galaxies (Wikisky/Riffle)
Image of spiral galaxy NGC 45 uploaded to Wikisky by Jim Riffle
Below, a labeled version of the image above, showing PGC 803099, 804519, 804799 and 3094764
Labeled version of image of spiral galaxy NGC 45 uploaded to Wikisky by Jim Riffle
Below, a 12 arcmin wide image centered on the galaxy; the "bright" star is 7th magnitude HD 941
Additional galaxies shown include PGC 3097980 (Wikisky/Riffle)
Labeled image of region near spiral galaxy NGC 45 uploaded to Wikisky by Jim Riffle, also showing numerous PGC objects

NGC 46
Recorded (Oct 22, 1852) by
Edward Cooper
Also observed (Sep 28, 1861) by Arthur von Auwers
A magnitude 11.7 star in Pisces (RA 00 14 09.9, Dec +05 59 16.0)
Historical Identification: Per Dreyer, NGC 46 (= GC 24, Markree Catalog, 1860 RA 00 06 59, NPD 84 47.5) is "a nebula (Auwers 2)". The position precesses to RA 00 14 10.1, Dec +05 59 14, exactly on the star listed above, so despite its not being a nebular object the identification is certain. Note: A Wikisky search for NGC 46 incorrectly shows NGC 469 (fortunately, correctly labeled as NGC 469), so the position must be used to see the correct object (there is a fairly common problem with Wikisky searches involving the number 9 either being added to or removed from search strings).
Discovery Notes: Dreyer's note "(Auwers 2)" only means that John Herschel used Auwers' catalog as the source for his entry for GC 24, and in some cases being included in Auwers' list of objects mostly discovered after 1845 does not mean that he actually observed the object. However, in his note for this entry Auwers stated "... I saw in that position on 1861 Sept 28 and 30 a completely sharp, nebulous star of 11th magnitude (9 arcmin north and 1 min 29 sec west of a star of 7.8 magnitude)." The (actually 7th magnitude) star in question (HD 1133) is exactly where Auwers placed it relative to Cooper's position, confirming that he and Cooper observed the same thing.
SDSS image of region near the star listed as NGC 46, also showing a PGC object
Above, a 12 arcmin wide region centered on NGC 46, also showing PGC 1292715

NGC 47 (=
NGC 58 = PGC 967)
Discovered (1886) by Wilhelm Tempel (and later listed as NGC 47)
Discovered (Oct 21, 1886) by Lewis Swift (and later listed as NGC 58)
A magnitude 13.1 spiral galaxy (type SB(rs)bc?) in Cetus (RA 00 14 30.6, Dec -07 10 03)
Historical Identification: Per Dreyer, NGC 47 (Tempel, 1860 RA 00 07 22, NPD 97 56.6) is "very faint, very small". The position precesses to RA 00 14 31.1, Dec -07 09 52, well within the outline of the galaxy listed above, so the identification is certain. See NGC 58 for a discussion of the duplicate listing.
Physical Information: Based on a recessional velocity of 5700 km/sec, NGC 47 is about 265 million light years away. Given that and its apparent size of 2.3 by 2.0 arcmin, it is about 175 thousand light years across.
SDSS image of region near spiral galaxy NGC 47
Above, a 12 arcmin wide SDSS image centered on NGC 47
Below, a 2.7 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy NGC 47
Below, a 12 arcmin wide SDSS image centered on NGC 47
Also shown are PGC 1022508, 1023173, 1023515, 1024587 and 1024725
SDSS image of region near spiral galaxy NGC 47, also showing several PGC objects

NGC 48 (= PGC 929)
Discovered (Sep 7, 1885) by
Lewis Swift
Also observed (Oct 13, 1890) by Guillaume Bigourdan
Also observed by Edward Barnard
A magnitude 13.6 spiral galaxy (type SBbc? pec) in Andromeda (RA 00 14 02.2, Dec +48 14 06)
Historical Identification: Per Dreyer, NGC 48 (Swift list II (#6), 1860 RA 00 07 27, NPD 42 31.8) is "most extremely faint, pretty large, round, very difficult". The second Index Catalog lists a corrected RA (per Bigourdan and Barnard) of 00 06 42; using that and the original NPD the position precesses to RA 00 14 01.6, Dec +48 14 56, only about 0.8 arcmin north of the center of the galaxy listed above and close to its northern end, so the identification is certain.
Physical Information: Despite the certainty of the identification of NGC 48, there must be conflicting identifications somewhere, because it has two listed recessional velocity values (1775 and 5250 km/sec), which obviously belong to completely different objects. As a result, whether it is about 85 million light years away (corresponding to the lower recessional velocity) or about 245 million light years away (corresponding to the higher recessional velocity) is unknown. There are a number of redshift-independent distance estimates, but they are equally confused, ranging from 85 to 200 million light years, so the distance of the galaxy is essentially unknown. Given the apparent size of 1.3 by 0.6 arcmin, if the distance is near the lower values it is about 30 thousand light years across; but if the distance is near the higher values the galaxy is about 90 thousand light years across. My guess, based on the appearance of the galaxy, is that it is more likely to be at the larger distance and have the larger size. But until sometime does new measurements, taking care to make sure they are for the correct object, the actual distance and size of NGC 48 will remain a mystery.
DSS image of region near spiral galaxy NGC 48, also showing NGC 49, NGC 51, IC 1534, IC 1535 and IC 1536 and one PGC object
Above, a 12 arcmin wide DSS image centered on NGC 48, also showing NGC 49 and 51
Also shown are IC 1534, 1535 and 1536, and PGC 212487
Below, a 1.5 arcmin wide DSS image of NGC 48
DSS image of spiral galaxy NGC 48

NGC 49 (= PGC 952)
Discovered (Sep 7, 1885) by
Lewis Swift
Also observed (Oct 13, 1890) by Guillaume Bigourdan
Also observed by Edward Barnard
A magnitude 13.7 lenticular galaxy (type S0?) in Andromeda (RA 00 14 22.4, Dec +48 14 47)
Historical Identification: Per Dreyer, NGC 49 (Swift list II (#7), 1860 RA 00 07 37, NPD 42 31.3) is "most extremely faint, small, round, 2nd of 3". The second Index Catalog lists a corrected RA (per Bigourdan and Barnard) of 00 07 02; using that and the original NPD the position precesses to RA 00 14 21.9, Dec +48 15 25, about 0.6 arcmin north of the center of the galaxy listed above, and not far from its northern border. Aside from that, it is obviously the "2nd of 3", or the middle galaxy among NGC 48, 49 and 51, so the identification is certain.
Physical Information: Based on a recessional velocity of 4775 km/sec, NGC 49 is about 220 million light years away. Given that and its apparent size of 1.05 by 0.75 arcmin, it is about 70 thousand light years across.
DSS image of lenticular galaxy NGC 49
Above, a 1.2 arcmin wide DSS image of NGC 49; see NGC 48 and 51 for wide-field images of the region
Celestial Atlas
(IC 5350 - 5386) ←     NGC Objects: NGC 1 - 49     → (NGC 50 - 99)