Historical Identification: Per Dreyer, NGC 2969 (= GC 1900 = JH 628 = WH III 527, 1860 RA 09 34 59, NPD 97 57.4) is "very faint, pretty small, irregularly round, very gradually a little brighter middle". The position precesses to RA 09 41 53.5, Dec -08 35 32, less than 0.7 arcmin north northwest of the center of the galaxy listed above (barely outside its outline), the description fits and there is nothing else nearby, so the identification is certain.
Physical Information: Based on a recessional velocity of 4960 km/sec, NGC 2969 is about 230 million light years away, in good agreement with redshift-independent distance estimates of 195 to 235 million light years. Given that and its apparent size of 1.5 by 1.35 arcmin, it is about 100 thousand light years across.

Historical Identification: Per Dreyer, NGC 2970 (= GC 1901 = JH 627, 1860 RA 09 35 13, NPD 57 23.1) is "faint, northeastern of 3", the others being NGC 2964 and 2968. (A note at the end of the NGC states that the object was not seen by d'Arrest, but was often observed at Birr Castle, confirming its existence.) The position precesses to RA 09 43 31.4, Dec +31 58 40, dead center on the galaxy listed above, and it is the northeastern of 3 (see the wide-field image of NGC 2968), so the identification is certain.
Physical Information: Based on a recessional velocity of 1620 km/sec, NGC 2970 is about 75 million light years away, in reasonable agreement with redshift-independent distance estimates of 85 to 95 million light years. Given that and its apparent size of 0.6 by 0.55 arcmin, it is about 15 thousand light years across. The estimated distances of NGC 2964, 2968 and 2970 are reasonably similar, and the differences in their radial velocities could easily be due to peculiar (non-Hubble expansion) velocities, so it is quite possible that the three apparent companions are members of a physical group. Even if so, how close they are to each other cannot be determined, but the distorted appearance of NGC 2968 suggests that it may be physically interacting with NGC 2970.

Historical Identification: Per Dreyer, NGC 2971 (Stephan list XIII (#50), 1860 RA 09 35 16, NPD 53 11.1) is "extremely faint, pretty small, irregularly round, a very little brighter middle". The position precesses to RA 09 43 45.9, Dec +36 10 39, well within the outline of the galaxy listed above and there is nothing else nearby, so the identification is certain.
Physical Information: Based on a recessional velocity of 6780 km/sec, NGC 2971 is about 315 million light years away. Given that and its apparent size of 1.4 by 0.9 arcmin, it is about 130 thousand light years across.

Historical Identification: Per Dreyer, NGC 2972 (= GC 1902 = JH 3183, Dunlop 397, 1860 RA 09 35 17, NPD 139 41.5) is a "cluster, small, a little rich, pretty compressed, 13th magnitude stars". The position precesses to RA 09 40 17.6, Dec -50 19 33, not far from the center of the cluster listed above and well within its boundaries, so the identification is certain. (See NGC 2999 for a discussion of the duplicate entry.)
Physical Information: Small clusters can be difficult to see against the background of the Milky Way in modern photographs (such as the one below), but the relatively constant brightness and color of NGC 2972's two dozen or so brighter stars make the cluster reasonably visible. The cluster is about 6700 light years away, so its apparent size of about 5 arcmin corresponds to 10 light years. Listed in LEDA as an object of unknown nature with designation PGC 3518275, but that designation is not recognized by a search of the LEDA database.

Historical Identification: Per Dreyer, NGC 2973 (= GC 1903 = JH 4018, hon, 1860 RA 09 35 23, NPD 119 24.7) is "extremely faint, pretty small, 8th magnitude star to east" ("hon" meaning that this was among a few objects observed by Herschel during his Cape Observations, but accidentally omitted from his catalog of those observations, and only found in the errata). The position precesses to RA 09 41 31.4, Dec -30 02 50, in a completely stellar field, so NGC 2973 is presumably some small group of stars. The "star to east" must be 9th magnitude HD 84084, so (per Corwin) the most likely candidates are the triple star about 0.7 arcmin due east of the NGC position but northwest of HD 84084, or the double star due west of HD 84084 but about 2.6 arcmin south of the NGC position. Either positional error would not be terribly unusual, so the reason that Corwin slightly prefers (and I greatly prefer) the triple listed above is that its 25 arcsec apparent size could easily appear to be closer to 40 arcsec as a result of "seeing", but the 10 arcsec separation of the double star could not possibly appear that large, and would almost certainly have been described by Herschel as "extremely small". So although the identification of NGC 2973 as the triple star cannot be considered absolutely certain, it seems certain enough. Note: LEDA lists PGC 27439 as NGC 2973, so although that is certainly wrong it is discussed in the next entry.
Discovery Notes: Guillaume Bigourdan tried to observe every NGC object visible from Paris, but in the case of NGC 2973, although he thought he might have seen something near its position on Mar 5, 1891, he was sufficiently uncertain whether what he thought he saw actually existed that he did not attempt to measure its position.
Physical Information: The 25 arcsec wide "asterism" consists of stars of magnitude 14.9, 15.6 and 15.7, and (although too faint for Herschel to have noticed) a 17.5 magnitude star close to the northeastern member of the triple. Whether they have any physical relationship to each other is almost certainly unknown.

Historical Misidentification: As noted above, LEDA misidentifies PGC 27439 as NGC 2973. If the position were "off" the NGC position by a simple offset in right ascension or declination, or the NGC description fit the galaxy, that might be reasonable. But there is no 8th magnitude star anywhere near the galaxy, and its offset of almost 4 minutes of time and 6 arcmin of declination would be a very unusual mistake; so probably whoever was doing the (mis)identification of NGC 2973 simply picked a nearby galaxy more or less at random, and PGC 27439 was the unlucky winner of the lottery.
Physical Information: Based on a recessional velocity of 4390 km/sec, PGC 27439 is about 205 million light years away. Given that and its apparent size of 1.3 by 0.9 arcmin, it is about 75 thousand light years across.

Historical Identification: Per Dreyer, NGC 2974 (= GC 1904 = JH 630 = WH I 61, 1860 RA 09 35 29, NPD 93 03.7) is "bright, considerably small, irregularly round, brighter middle, 9th magnitude star 43 arcsec to southwest". The position precesses to RA 09 42 32.9, Dec -03 41 54, right on the galaxy listed above, there is nothing else nearby and the star on its southwestern outline makes the identification certain.
NGC Designation: Stone's right ascension was an hour of time west of the correct position, making the duplicate entry inevitable, but his description was perfect, so there is no doubt about the identity of the duplicate listing. Usually, this would mean that the galaxy would be referred to by the smaller entry number (as NGC 2652), but the identity of NGC 2652 was unknown until very recently, and after more than 120 years calling this galaxy NGC 2974 most references are reluctant to change its designation, so in this case the entry for NGC 2652 is treated as the duplicate, and NGC 2974 is treated as the main entry.
Physical Information: The galaxy is usually classified as elliptical, but it has a large number of (presumably) circular patterns centered on the nucleus, suggesting that it is actually a lenticular galaxy, with peculiar aspects more characteristic of a spiral galaxy (whence its type shown above). Based on a recessional velocity of 1885 km/sec, NGC 2974 is about 90 million light years away, in good agreement with widely varying redshift-independent distance estimates of 40 to 160 million light years. Given that and its apparent size of about 3.6 by 2.4 arcmin, it is about 90 thousand light years across. Listed as a Seyfert galaxy (type Sy 2).

Historical Identification: Per Dreyer, NPD 2975 (Ormond Stone list I (#157), 1860 RA 09 35 35, NPD 106 00.8) is "most extremely faint, small, round, gradually brighter middle". The position precesses to RA 09 42 13.6, Dec -16 38 59, but there is nothing there. Bigourdan failed to find anything near the supposed position on Jan 23, 1890, so a problem was known to exist very early on, but there appears to be no mention of how an identification of NGC 2975 with the galaxy listed above was made. Odds are that it is based on the fact that Leander McCormick Observatory positions were often off by a minute or two in right ascension, and if the right ascension recorded by Stone is reduced by one minute, the "corrected" position precesses to RA 09 41 13.9, Dec -16 38 58, about 1.5 arcmin north northwest of the galaxy listed above. The description fits and there is nothing else anywhere near the parallel of declination, so the identification is reasonable, though not as certain as it would be if there was a sketch of the region or a note such as "star to northwest". And though there is nothing to say whether this is the line of reasoning that was followed, there is also nothing to indicate that anyone has questioned the identification, so it is at least (hopefully!) better than nothing.
Physical Information: Based on a recessional velocity of 16200 km/sec, a straightforward calculation indicates that NGC 2975 is about 755 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 710 million light years away at the time the light by which we see it was emitted, about 725 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 0.4 by 0.35 arcmin, it is about 80 thousand light years across.

Historical Identification: Per Dreyer, NGC 2976 (= GC 1905 = JH 625 = WH I 285, 1860 RA 09 35 36, NPD 21 26.6) is "bright, very large, much extended 152°, star involved". The position precesses to RA 09 47 12.7, Dec +67 54 55, right on the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain.
Physical Information: NGC 2976's recessional velocity of only 5 km/sec is useless for determining its distance, and redshift-independent distance estimates range from 7 to 19 million light years, with a median value of 12 million light years. Presuming the median is reasonably accurate, the galaxy's apparent size of 4.7 by 2.6 arcmin corresponds to about 15 thousand light years. The galaxy is on the fringe of the M81 group of galaxies, and it is believed that interaction with galaxies in that group stripped its outer regions of gas about 500 million years ago, so that new stars are now forming only within a 5000 light year wide region at the center of the galaxy.

Historical Identification: Per Dreyer, NGC 2977 (= GC 1906 = WH I 282, 1860 RA 09 35 48, NPD 14 15.1) is "considerably bright, pretty large, irregular figure (place doubtful)". This precesses to RA 09 49 43.9, Dec +75 06 16, but as the "doubtful" position might lead us to expect, there is nothing there. A note at the end of the NGC states that all Herschel's discoveries of April 2, 1801 (I 282-284, II 903-905 and III 963 - 971) were affected by some large error. In that note Dreyer assumes the problem was due to all the observations being compared with a single star which was presumably misidentified, but that proved to be incorrect, as discussed in the Discovery Notes below. However, thanks to a 1911 request by Dreyer for the Astronomer Royal to photograph the region involved, in Dreyer's 1912 publication of corrections to Herschel's observations he was able to state "The place according to Greenwich plate is (1860 RA) 09 29 42, (NPD) 14 30.5.". This precesses to RA 09 43 45.9, Dec +74 51 34, dead center on the galaxy listed above, so the identification is certain.
Discovery Notes: As noted above, Herschel's positions for everything he observed on Apr 2, 1801 were very poor. Dreyer assumed that this was due to his using an incorrect comparison star, but though he was correct in recognizing the problem, his suggestion as to its cause was not correct. In 2011-12 Steinicke showed that instead of Herschel placing his telescope on the meridian, as was his usual practice, he must have placed it 7 degrees off the meridian (corresponding to an error of 28 minutes of time in right ascension), causing his sister Caroline's reductions to be off by some fraction of that 7 degrees, depending upon the declination of the objects observed. A long note by Corwin for NGC 3752 discusses the matter in great detail, firmly establishing the identities of all the NGC objects in question on the basis of Steinicke's recalculations and the ROG (Royal Observatory Greenwich) plates.
Physical Information: Based on a recessional velocity of 3050 km/sec, NGC 2977 is about 140 million light years away, in good agreement with redshift-independent distance estimates of 140 to 145 million light years. Given that and its apparent size of 1.5 by 0.65 arcmin, it is about 60 thousand light years across.

Historical Identification: Per Dreyer, NGC 2978 (Swift list III (#46), 1860 RA 09 36 09, NPD 99 07.7) is "extremely faint, small, round, III 528 ten arcmin to north", III 528 being NGC 2980. The second IC lists a corrected RA (per Howe) of 09 36 25. The corrected NGC position precesses to RA 09 43 17.4, Dec -09 46 00, about 1.2 arcmin south of the galaxy listed above, and Howe's actual position of (1900) RA 09 38 23, Dec -09 17.3 falls right on the galaxy. The description fits, there is nothing else nearby, and NGC 2980 is about 8 arcmin to the north, so the identification is certain.
Physical Information: The NED lists two recessional velocities, 1800 km/sec and 5645 km/sec. The former corresponds to a distance of only 85 million light years, while the latter corresponds to a distance of 265 million light years. Redshift-independent distance estimates range from 135 to 330 million light years, with a median value much closer to the larger distance, implying that the 1800 km/sec recessional velocity is wrong, presumably due to a misidentification of the object that the radial velocity belongs to. (This is one of the reasons for trying to determine exactly which galaxies correspond to a given designation.) Given a distance of 265 million light years, the galaxy's apparent size of 0.95 by 0.85 arcmin corresponds to about 75 thousand light years, which is a far more reasonable value for a galaxy of its appearance than the much smaller value that would correspond to the (almost certainly incorrect) smaller distance.

Historical Identification: Per Dreyer, NGC 2979 (= GC 1907 = JH 631 = WH III 521, 1860 RA 09 36 17, NPD 99 44.7) is "pretty faint, pretty small, a very little extended, pretty suddenly bright middle". The position precesses to RA 09 43 08.2, Dec -10 22 59, right on the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain. (See NGC 3050 for a discussion of the double listing.)
Physical Information: Based on a recessional velocity of 2720 km/sec, NGC 2979 is about 125 million light years away. Given that and its apparent size of 1.5 by 0.9 arcmin, it is about 55 thousand light years across. It is listed as a Seyfert galaxy (type Sy 2).

Historical Identification: Per Dreyer, NGC 2980 (= GC 1908 = JH 632 = WH III 528, 1860 RA 09 36 18, NPD 98 58.0) is "very faint, pretty small, a little extended 0°, very gradually a little brighter middle". The position precesses to RA 09 43 10.7, Dec -09 36 17, on the northwestern rim of the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain.
Physical Information: Based on a recessional velocity of 5720 km/sec, NGC 2980 is about 265 million light years away, in good agreement with redshift-independent distance estimates of 225 to 335 million light years. Given that and its apparent size of 1.75 by 0.75 arcmin, it is about 135 thousand light years across.

Historical Identification: Per Dreyer, NGC 2981 (Palisa, 1860 RA 09 36 40, NPD 58 14.3) is "very faint". The position precesses to RA 09 44 55.6, Dec +31 07 18, less than 1.5 arcmin north of the galaxy listed above and there is nothing else nearby, so the identification is certain.
Discovery Notes: Although Dreyer credits Palisa with the observation, the paper published by Dr. Weiss of the Vienna Observatory which reported the observation used variations of the Greek letter π (pi) to indicate observations by Palisa, and the observation that became NGC 2981 is marked with an ω (omega). In the remarks for Dr. Weiss' paper there is no indication of anyone who might be associated with that symbol, but Dr. Oppenheim's observations are indicated by variations on the letter ο (omicron), and Steinicke supposes the omega to be an incorrect indication that Oppenheim was the observer. However, every other nebula listed in the paper by Dr. Weiss was observed by Palisa, and he observed two other objects only a few minutes of time to the west on the night in question (which probably means only a few minutes earlier), so it seems far more likely that Palisa was the actual observer, and the omega was supposed to be a pi.
Physical Information: Based on a recessional velocity of 10405 km/sec, a straightforward calculation indicates that NGC 2981 is about 485 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 465 million light years away at the time the light by which we see it was emitted, about 475 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 1.0 arcmin, the galaxy is about 160 thousand light years across.

Historical Identification: Per Dreyer, NGC 2982 (= GC 1910 = JH 3184, (Dunlop #468), 1860 RA 09 36 52, NPD 133 33.7) is a "cluster, poor, extended, stars from 10th to 11th magnitude". The position precesses to RA 09 42 18.8, Dec -44 11 58, but there is nothing there. Per Corwin the problem is due to the fact that the NPD published in Herschel's Cape of Good Horn observations actually belongs to the next object observed that night; so although the right ascension might be reasonably accurate, the declination could be off by half a degree or more, depending upon how much Herschel moved his telescope north and south while allowing the sky to sweep past his field of view. Based on Herschel's description ("A cluster of about 20 stars 11 m, and 2 of 10' [10.5] m, forming an oblong nearly in parallel."), the cluster should consist of a number of bright stars scattered along an east-west line. The cluster listed above is only 12 arcmin north of the invalid declination, perfectly fits Herschel's description, and as a result is generally considered to be NGC 2982.
Discovery Notes: Dreyer did not list Dunlop's observations unless confirmed by Herschel, so the prior discovery is not noted in the NGC entry; but later study has determined that Dunlop did observe this object, hence the inclusion of his observation in parentheses. As shown above, LEDA lists the cluster as PGC 3518276; but that designation is not recognized by a search of the LEDA database.
Physical Information: NGC 2982 is believed to be a little over 8000 light years away. Given that and its apparent size of 12 by 7 arcmin, it is about 30 light years across.

Historical Identification: Per Dreyer, NGC 2983 (= GC 1911 = JH 3185 = WH III 289, 1860 RA 09 37 08, NPD 109 49.9) is "faint, pretty small, round, brighter middle, mottled but not resolved, stellar". The position precesses to RA 09 43 39.0, Dec -20 28 16, on the northwestern rim of the galaxy listed above and there is nothing else nearby, so the identification is certain.
Discovery Notes: A note at the end of the NGC quotes John Herschel but adds nothing to the NGC entry, so is added here only in passing: "h 3185 = III 289. P.D. of Auwers 5' too small, owing to a misprint in P. T.". And in a 1900 paper, Howe states that a 14th magnitude star is "a trifle north" and 2 seconds of time to the west (in the images below this is the star superimposed on the image of the galaxy, about halfway from the nucleus to the western rim of the galaxy).
Physical Information: Based on a recessional velocity of 2030 km/sec, NGC 2983 is about 95 million light years away, in good agreement with redshift-independent distance estimates of 70 to 135 million light years. Given that and its apparent size of 2.4 by 1.4 arcmin, it is about 65 thousand light years across.

Historical Identification: Per Dreyer, NGC 2984 (= GC 1912 = JH 633 = WH III 34, 1860 RA 09 37 23, NPD 78 20.2) is "extremely faint, very small, round, brighter middle (? PD 15')", the query meaning that John Herschel considered his position only approximate, and thought perhaps his father's position, which was north of his own, might be more accurate. The NGC position precesses to RA 09 44 54.6, Dec +11 01 21, while the more northerly position precesses to RA 09 44 54.8, Dec +11 06 33. Both positions lie in a completely stellar region, but there is a reasonable candidate a minute to the west of them lying between the two declinations, namely the galaxy accurately measured by Javelle and then listed as IC 556. In the 1920's Karl Reinmuth, after doing a survey of the elder Herschel's observations, suggested that IC 556 was NGC 2984, and that suggestion has been generally accepted for nearly a century, as indicated by the title of this entry.
Discovery Notes: William Herschel's comparison star was 5 (ξ) Leonis, whose modern position is J2000 RA 09 31 56.7, Dec +11 17 59. In the 216 years since Herschel's observation, its proper motion has reduced the star's right ascension by 0.1 seconds of time and 19 seconds of arc, so in 1784 it was at J2000 RA 09 31 56.8, Dec +11 18 18, or (1784) RA 09 20 15.7, Dec +12 14 48. Herschel's offsets were 13 minutes of time east and 10 arcmin south of the star, so III 34 should have been at (1784) RA 09 33 15.7, Dec +12 04 48, which precesses to J2000 RA 09 44 53.5, Dec +11 05 51, just over a minute of time east and 2 arcmin north of IC 556. IC 557 is also in the region, but it is half a magnitude fainter than IC 556, which is already near the limit of the Herschels' ability to observe faint nebulae, and its nucleus (which is all the Herschels could have seen of either galaxy) is much fainter, so it is considered a far less likely candidate.
Physical Information: Based on a recessional velocity of 6225 km/sec, NGC 2984 is about 290 million light years away. Given that and its apparent size of 0.7 by 0.6 arcmin, it is about 60 thousand light years across.

Historical Identification: Per Dreyer, NGC 2985 (= GC 1909 = JH 629 = WH I 78, 1860 RA 09 37 38, NPD 17 04.5) is "very bright, considerably large, round, pretty suddenly much brighter middle, star involved to east". The position precesses to RA 09 50 22.1, Dec +72 16 43, dead center on the galaxy listed above, the description fits (including the "star involved to east") and there is nothing else nearby, so the identification is certain.
Discovery Notes: In Dreyer's 1877 GC Supplement he notes that (per d'Arrest and G. Rümker) the RA for John Herschel's GC 1909 was a minute of time too small. That correction is included in the NGC entry, but means that d'Arrest and Rümker should be listed as other observers, as I have done above.
Physical Information: Based on a recessional velocity of 1320 km/sec, NGC 2985 is about 60 million light years away, in reasonable agreement with redshift-independent distance estimates of 65 to 75 million light years. Given that and its apparent size of about 7 by 6 arcmin, it is about 130 thousand light years across, counting its faint outer arms. It is listed as a Seyfert galaxy (type Sy 1.9).

Historical Identification: Per Dreyer, NGC 2986 (= GC 1913 = WH II 311, Engelhardt, 1860 RA 09 37 47, NPD 110 38.3) is "pretty bright, pretty small, irregularly round, much brighter middle". The position precesses to RA 09 44 16.4, Dec -21 16 44, right on the galaxy listed above, the description fits and there is nothing comparable nearby, so the identification is certain.
Physical Information: Based on a recessional velocity of 2300 km/sec, NGC 2986 is about 105 million light years away, in good agreement with redshift-independent distance estimates of 70 to 155 million light years. Given that and its apparent size of 5.0 by 4.0 arcmin, it is about 155 thousand light years across.

Historical Identification: Per Dreyer, NGC 2987 (Stephan list XIII (#51), 1860 RA 09 38 22, NPD 84 25.0) is "extremely faint, small, irregular figure, several very faint stars involved". The position precesses to RA 09 45 42.0, Dec +04 56 27, right on the galaxy listed above and there is nothing else nearby, so the identification is certain.
Physical Information: Based on a recessional velocity of 3740 km/sec, NGC 2987 is about 175 million light years away, in good agreement with redshift-independent distance estimates of 175 to 185 million light years. Given that and its apparent size of 1.45 by 0.7 arcmin, it is about 75 thousand light years across.

Historical Identification: Per Dreyer, NGC 2988 (= GC 1916, 3rd Lord Rosse, 1860 RA 09 38 50, NPD 67 21) is "extremely faint, west of h634", h634 being NGC 2991. The position precesses to RA 09 46 43.6, Dec +22 00 22, just over an arcmin west southwest of the galaxy listed above, but the reference to NGC 2991 and the lack of anything else in the region makes the identification certain.
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 7610 km/sec, a straightforward calculation indicates that NGC 2988 is about 355 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 345 million light years away at the time the light by which we see it was emitted, about 350 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 0.75 by 0.15 arcmin, it is about 75 thousand light years across. The recessional velocity of NGC 2988 is sufficiently similar to that of its apparent companion (NGC 2991) that they may be a physical pair; and if so, the slightly distorted appearance of NGC 2991 suggests that they may be close enough to have interacted with each other at some time.

Historical Identification: Per Dreyer, NGC 2989 (= GC 1915 = JH 3186, 1860 RA 09 38 52, NPD 107 44.4) is "faint, round, gradually brighter middle, double star to east". The position precesses to RA 09 45 27.7, Dec -18 22 58, only about 0.8 arcmin southeast of the galaxy listed above, the description fits (including the double star to the southeast) and there is nothing else nearby, so the identification is certain.
Physical Information: Based on a recessional velocity of 4145 km/sec, NGC 2989 is about 195 million light years away, in good agreement with redshift-independent distance estimates of 135 to 210 million light years. Given that and its apparent size of about 2.5 by 1.05 arcmin (including its extended outer arms), it is about 140 thousand light years across. NGC 2989 is listed as a starburst galaxy.

Historical Identification: Per Dreyer, NGC 2990 (= GC 1914 = WH II 624, d'Arrest, 1860 RA 09 38 56, NPD 83 38.3) is "faint, pretty small, a little extended 90°" (Herschel's position was poor, so Dreyer used d'Arrest's position, which was 1860 RA 09 38 56.5, NPD 83 38 16). The position precesses to RA 09 46 17.4, Dec +05 43 05, only half an arcmin north of the galaxy listed above, the description fits and there is nothing comparable nearby, so the identification is certain.
Physical Information: Based on a recessional velocity of 3090 km/sec, NGC 2990 is about 145 million light years away, in good agreement with redshift-independent distance estimates of 95 to 150 million light years. Given that and its apparent size of 1.15 by 0.6 arcmin, it is about 50 thousand light years across.

Historical Identification: Per Dreyer, NGC 2991 (= GC 1917 = JH 634, 1860 RA 09 38 57, NPD 67 20.5) is "faint, very small, brighter middle, southwestern of 2", the other being NGC 2994. The position precesses to RA 09 46 50.6, Dec +22 00 51, right on the galaxy listed above, the description fits (including its position relative to NGC 2994) and there is nothing comparable nearby, so the identification is certain.
Discovery Notes: The identity of the galaxy on its western rim, NGC 2988 was confirmed by its position relative to NGC 2991, as noted in its entry.
Physical Information: Based on a recessional velocity of 7455 km/sec, a straightforward calculation indicates that NGC 2991 is about 345 million light years away, in fair agreement with redshift-independent distance estimates of 370 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 335 million light years away at the time the light by which we see it was emitted, about 340 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 0.7 arcmin, it is about 100 thousand light years across. The recessional velocity of NGC 2991 is sufficiently similar to that of its apparent companion (NGC 2988) that they may be a physical pair; and if so, the slightly distorted appearance of NGC 2991 suggests that they may be close enough to have interacted with each other at some time.

Historical Identification: Per Dreyer, NGC 2992 (= GC 1918 = JH 635 = WH III 277, 1860 RA 09 38 58, NPD 103 41.1) is "considerably faint, small, round, brighter middle, stellar, western of 2", the other being NGC 2993. The position precesses to RA 09 45 41.9, Dec -14 19 41, right on the galaxy listed above, the description fits and save for the "eastern of 2" there is nothing else nearby, so the identification is certain.
Physical Information: The distended portions of NGC 2992 and NGC 2993 make it clear that they are interacting, and therefore at the same distance. The recessional velocity of NGC 2992 is 2310 km/sec, while that of NGC 2993 is 2430 km/sec, but the difference of 120 km/sec must represent their "peculiar velocity" (their non-Hubble expansion velocity relative to each other), so their average recessional velocity should be used to estimate their Hubble distance. That value of 2370 km/sec corresponds to a distance of about 110 million light years, in good agreement with redshift-independent distance estimates of 95 to 125 million light years for NGC 2992, and 100 million light years for NGC 2993. Given that and its apparent size of 1.75 by 0.7 arcmin, the main body of NGC 2992 is about 55 thousand light years across, while its distorted outer extensions' apparent size of 4.5 by 1.45 arcmin corresponds to about 145 thousand light years. The entire system, including the distorted outer extensions of both galaxies, has an apparent size of 7.9 by 3.5 arcmin, corresponding to about 255 thousand light years. NGC 2992 is listed as a Seyfert galaxy (type Sy 1.9).

Historical Identification: Per Dreyer, NGC 2993 (= GC 1919 = JH 637 = WH III 278, 1860 RA 09 39 05, NPD 103 43.4) is "considerably faint, small, round, brighter middle, stellar, eastern of 2", the other being NGC 2992. The position precesses to RA 09 45 48.8, Dec -14 22 00, right on the galaxy listed above, the description fits and save for the "western of 2" there is nothing else nearby, so the identification is certain.
Physical Information: Based on the discussion of distances in the entry for NGC 2992, NGC 2993 must be about 110 million light years away. Given that, its central region's apparent size of 1.2 by 1.1 arcmin corresponds to about 40 thousand light years, while the 4.5 by 2.4 arcmin apparent size including its distorted outer extensions corresponds to about 145 thousand light years. The entire system, including the distorted outer extensions of both galaxies, has an apparent size of 7.9 by 3.5 arcmin, corresponding to about 255 thousand light years.

Historical Identification: Per Dreyer, NGC 2994 (= GC 1920 = JH 636, 1860 RA 09 39 22, NPD 67 15.9) is "faint, small, round, brighter middle, northeastern of 2", the other being NGC 2991. The position precesses to RA 09 47 15.6, Dec +22 05 24, right on the galaxy listed above, the description fits (including the reference to the other nebula) and there is nothing else nearby, so the identification is certain.
Physical Information: Based on a recessional velocity of 7385 km/sec, a straightforward calculation indicates that NGC 2994 is about 345 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 335 million light years away at the time the light by which we see it was emitted, about 340 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 1.1 by 0.6 arcmin, the galaxy is about 105 thousand light years across.

Historical Identification: Per Dreyer, NGC 2995 (= GC 1921 = JH 3189, 1860 RA 09 39 22, NPD 144 08.0) is a "cluster, poor, a little compressed". The position precesses to RA 09 44 03.7, Dec -54 46 31, but there is nothing there that resembles any kind of cluster. However (per Corwin), there is a group of stars about 10 arcmin north of Herschel's position that seems to fit his original description: "...at least 20 stars 11th magnitude and upwards, and many smaller". Given Herschel's poor position and the uncertain description of the "cluster" given below, whether either group of stars listed above is what Herschel observed cannot be known, but they probably represent the best "educated guess" that can be made, so the identification is considered reasonably certain. Listed in LEDA as a group of stars with designation PGC 5067533, but that designation is not recognized by a search of the LEDA database.
Physical Information: The group centered near the first position listed above consists of an approximately 8 by 5 arcmin wide clump of stars, as shown in the 15 arcmin wide view below. The group centered near the second position consists of the smaller group plus extensions to the north and east covering a region about 20 by 20 arcmin, as shown in the 30 arcmin wide view below. So the smaller, denser clump of stars is thought to be part of NGC 2995 regardless of how that object is defined; but whether it is a real cluster or merely an accidental scattering of stars is not known.

Historical Identification: Per Dreyer, NGC 2996 (= GC 1922 = JH 3187, 1860 RA 09 39 28, NPD 110 56.8) is "very faint, small, 20th magnitude star 1 arcmin to east". Given the technology of the day, the 20th magnitude star is an obvious misprint; the second IC lists a corrected RA (per Howe) of 09 40 01 and adds "The star to the east is of 9th magnitude, not 20th". The position precesses to RA 09 46 30.3, Dec -21 35 30, just over an arcmin south of the galaxy listed above, but there is nothing else nearby and the 10th magnitude star just east of the galaxy makes the identification certain.
Physical Information: Based on a recessional velocity of 8775 km/sec, a straightforward calculation indicates that NGC 2996 is about 419 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 395 million light years away at the time the light by which we see it was emitted, about 400 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 0.6 by 0.5 arcmin, the central galaxy is about 70 thousand light years across, but the distorted extensions surrounding the galaxy have an apparent size of 2.7 by 1.6 arcmin, corresponding to about 310 thousand light years. Note: The "type" of NGC 2996 is very uncertain, "peculiar" being the most telling part of its description; but it reminds me of NGC 7252, the Atoms for Peace galaxy, so I have tentatively assigned it the same type.

Historical Identification: Per Dreyer, NGC 2997 (= GC 1923 = JH 3188 = WH V 50, (Dunlop 622), 1860 RA 09 39 33, NPD 120 32.8) is "a remarkable object, very faint, very large, very gradually then very suddenly bright middle and 4 arcsec nucleus, 19.5s d". The position precesses to RA 09 45 40.2, Dec -31 11 25, nearly dead center on the galaxy listed above and the description fits (the last comment referring to the double star 22 seconds of time distant (east) of the nucleus, not far from the left side of the wide-field image below), so the identification is certain.
Discovery Notes: Dreyer did not list Dunlop's observations unless confirmed by Herschel, so Dunlop's observation is not noted in the NGC entry; but later study has determined that Dunlop did observe this object, hence the inclusion of his observation in parentheses.
Physical Information: Based on a recessional velocity relative to the Cosmic Microwave Background radiation of 1405 km/sec (and H₀ = 70 km/sec/Mpc), NGC 2997 is about 65 million light years away, much further than redshift-independent distance estimates of about 25 to 45 million light years (the ESO press release uses a distance of about 30 million light years). Given its apparent size of about 9.8 by 9.0 arcmin (from the images below), if it is about 30 million light years away the galaxy is about 85 thousand light years across; but if it is actually 65 million light years distant, it would be about 185 to 190 thousand light years across.
Note About The Distance: It is not unusual for distances based on recessional velocities of galaxies to differ from those determined in other ways, and to a certain extent it can be expected, as galaxies typically have "peculiar velocities" (motions relative to the other galaxies in their vicinity) of a hundred or two km/sec for galaxies that are in small groups or "on their own", and as much as a thousand km/sec if they are in gigantic clusters with hundreds or thousands of other members, whose combined gravity can cause galaxies passing through the cluster to acquire very high peculiar velocities, particularly if they are passing through or near the center of the cluster. However, for a galaxy such as NGC 2997 to have a peculiar velocity of 7 or 8 hundred km/sec relative to its neighbors is very puzzling. So either it is close to its supposed neighbors and there is some drastic error in the recessional velocity, or the numerous redshift-independent distance estimates are completely wrong (which is not unusual if there are only one or two such estimates, but in this case there are more than a dozen, which makes it unlikely that they are all wrong). Given this, I have chosen to use the 30 million light year distance (which is the mean of the various redshift-independent distance estimates) for the first (and most likely best) estimate of the galaxy's distance and physical size; and will have to wait for future measurements of the galaxy's "redshift" to find out whether there is a problem with the recessional velocity quoted above.

Historical Identification: Per Dreyer, NGC 2998 (= GC 1924 = JH 638 = WH II 717, 1860 RA 09 40 02, NPD 45 15.5) is "pretty faint, pretty large, extended 51°, brighter middle and nucleus, mottled but not resolved". The position precesses to RA 09 48 54.5, Dec +44 05 40, just over 2 arcmin northeast of the galaxy listed above, but the description fits and there is nothing comparable nearby, so the identification is certain.
Discovery Notes: A note at the end of the GC states "h638 and group (the nebulae to the east of NGC 2998). The places are founded on my obs. of 1878, Apr. 1. GC 1936-37 (and Lord Rosse's) novae near h641 (= NGC 3010) have been omitted, as the obs. of 1854, Mar. 1, was no doubt of h638 and group, and not of h640-41." In other words, Dreyer's own observations were used for the positions listed in the NGC for a number of nebulae near NGC 2998, and observations made by Lord Rosse or his assistants that were listed by John Herschel as GC 1936 and 1937 were not novae near NGC 3010 but reobservations of objects near NGC 2998, and were therefore not given their own (erroneous) NGC entries. (For those wondering why GC 1936 and 1937 are not listed in the NGC, this explains their absence.)
Physical Information: Based on a recessional velocity of 4785 km/sec, NGC 2998 is about 225 million light years away, in good agreement with redshift-independent distance estimates of 145 to 225 million light years. Given that and its apparent size of 3.2 by 1.3 arcmin, it is about 210 thousand light years across.

Historical Identification: Per Dreyer, NGC 2999 (= GC 1927 = JH 3191, Dunlop 397, 1860 RA 09 40 05, NPD 139 47.2) is a "cluster, small, a little rich, irregular figure, stars from 12th to 15th magnitude". The position precesses to RA 09 45 09.0, Dec -50 25 49, but there is nothing there (in fact, because the position lies in front of an extended dust-filled region there are fewer visible stars in the region than usual). However, Herschel was fully aware that the position might be wrong, stating at the end of his Cape of Good Hope description "Observed for Dunlop 397, and place only rough. Possibly the same object with (sweep) 680, No. 27, which see above (No. 3183)", JH 3183 being NGC 2972. The Cape of Good Hope description is not the same as for JH 3183, but is not sufficiently different to rule out its being the same stellar grouping, and the descriptions of the two entries in the General Catalog are more nearly identical. To show how uncertain Herschel was of the situation, in the Cape of Good Hope observations JH 3183 is listed as Dunlop 397, but in the General Catalog JH 3191 is listed as Dunlop 397, so Herschel clearly had no idea which if either of the two observations was correct. Despite that, given the nearly 5 minutes of time difference in right ascension and more than 5 arcmin difference in declination, he felt obliged to list the two observations as separate objects in the GC, and as a result Dreyer did the same in the NGC, producing an almost certainly duplicate entry. It should be noted that such a situation is not unusual for observers who "sweep" the heavens (that is, observe objects in a limited range of declinations while the westward movement of the sky causes the telescope to "sweep" eastward in the sky), as objects observed in one sweep can easily be mistaken for an apparently different object in a subsequent sweep just north or south of the original one, and many observers using that technique in the era of visual observations occasionally ended up with duplicate entries in their catalogs as a result of mis-measurements in one sweep or another. Given the preceding, it seems very reasonable to identify NGC 2999 and 2972 as duplicate observations of the same object, and as a result this identification of NGC 2999 has been generally (and probably universally) accepted.
Physical Information: Given the almost certain duplicate entry, see NGC 2972 for anything else (including the nonsensical PGC designation).