Celestial Atlas
(NGC 4550 - 4599) ←NGC Objects: NGC 4600 - 4649 Link for sharing this page on Facebook→ (NGC 4650 - 4699)
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4600, 4601, 4602, 4603, 4604, 4605, 4606, 4607, 4608, 4609, 4610, 4611, 4612, 4613, 4614, 4615, 4616,
4617, 4618, 4619, 4620, 4621, 4622, 4623, 4624, 4625, 4626, 4627, 4628, 4629, 4630, 4631, 4632, 4633,
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Page last updated Apr 29, 2020
Completed entries for NGC 4602/4604 (though not for "old" 4604)
Checked Corwin updated positions, added Dreyer entries, checked Steinicke databases
CURRENT WORK: Updating formatting to current standards as work on page
WORKING 4637/8+: Precess 1860 positions to find current NGC positions and likely IDs
NEXT: Check Gottlieb's site, Corwin's ID comments
NEXT: Check physical characteristics, add pix/tags

NGC 4600 (= PGC 42447)
Discovered (Apr 30, 1786) by
William Herschel
Also observed (Apr 7, 1828) by John Herschel
A magnitude 12.7 lenticular galaxy (type S0?) in Virgo (RA 12 40 23.0, Dec +03 07 04)
Historical Identification: Per Dreyer, NGC 4600 (= GC 3138 = JH 1379 = WH II 577, 1860 RA 12 33 14, NPD 86 06.6) is "faint, small, round, 2 stars of 8th magnitude to east". The position precesses to RA 12 40 22.5, Dec +03 07 14, on the northwest rim of the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 1.2 by 0.8 arcmin? Listed as a member (VCC 1834) of the Virgo Cluster.

NGC 4601 (= PGC 42492 = ESO 322-050)
Discovered (Jun 8, 1834) by
John Herschel
A magnitude 13.4 lenticular galaxy (type SB0/a?) in Centaurus (RA 12 40 46.7, Dec -40 53 35)
Historical Identification: Per Dreyer, NGC 4601 (= GC 3139 = JH 3405, 1860 RA 12 33 24, NPD 130 09.0) is "extremely faint, large, round, pretty suddenly a little brighter middle, western of 2", the other being NGC 4603. The position precesses to RA 12 41 00.1, Dec -40 55 10, about 3 arcmin east southeast of the galaxy listed above, but that is fairly similar to the positional error for NGC 4603, the description is a reasonable fit to the visual appearance of the galaxy, and since the two nebulae are listed as the preceding and following members "of 2", the similarity of their positional errors essentially confirms the identification of NGC 4601.
Physical Information: Apparent size 1.7 by 0.5 arcmin?

NGC 4602 (= PGC 42476, and almost certainly =
NGC 4604)
Discovered (Apr 24, 1784) by William Herschel (and laer listed as NGC 4602)
Also observed (Feb 19, 1830) by John Herschel (and later listed as NGC 4602)
Also observed (1883) by Christian Peters (and later listed as NGC 4604)
A magnitude 11.5 spiral galaxy (type SAB(rs)bc) in Virgo (RA 12 40 36.9, Dec -05 07 58)
Historical Identification: Per Dreyer, NGC 4602 (= GC 3140 = JH 1380 = WH II 184, 1860 RA 12 33 27, NPD 94 21.8) is "faint, large, extended, very gradually a little brighter middle". The position precesses to RA 12 40 39.8, Dec -05 07 58, on the eastern rim of the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain. (See NGC 4604 for a discussion of the duplicate entry.)
Physical Information: Based on a recessional velocity relative to the Cosmic Microwave Background radiation of 2885 km/sec (and H0 = 70 km/sec/Mpc), NGC 4602 is about 135 million light years away, in reasonable agreement with redshift-independent distance estimates of about 70 to 125 million light years. Given that and its apparent size of about 4.1 by 1.1 arcmin (from the images below), the galaxy is about 160 thousand light years across. NGC 4602 is listed as a Seyfert galaxy (type Sy1.9).
SDSS image of the region near spiral galaxy NGC 4602, which is probably also NGC 4604
Above, a 12 arcmin wide SDSS image centered on NGC 4602
Below, a 5 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy NGC 4602, which is probably also NGC 4604
Below, a 3 by 5 arcmin wide image of the galaxy (witht North on the right, to allow for more detail)
(Image Credit & © Carnegie-Irvine Galaxy Survey; used by permission)
Carnegie-Irvine Galaxy Survey image of spiral galaxy NGC 4602, which is probably also NGC 4604

NGC 4603 (= PGC 42510 = PGC 580396 = ESO 322-052)
Discovered (Jun 8, 1834) by
John Herschel
A magnitude 11.4 spiral galaxy (type SAB(s)bc?) in Centaurus (RA 12 40 55.2, Dec -40 58 35)
Historical Identification: Per Dreyer, NGC 4603 (= GC 3141 = JH 3406, 1860 RA 12 33 31, NPD 130 12.0) is "faint, large, round, very gradually brighter middle, mottled but not resolved". The position precesses to RA 12 41 07.3, Dec -40 58 09, about 2.4 arcmin east northeast of the galaxy listed above, but the description fits and there is nothing comparable nearby, so the identification is certain. (Note that the fairly similar error in the NGC position of NGC 4601 essentially confirms the identification of that object, stated as being the western member "of 2" with NGC 4603, as well.)
Physical Information: Based on a recessional velocity relative to the Cosmic Microwave Background radiation of 2879 km/sec (and H0 = 70 km/sec/Mpc), NGC 4603 is about 135 million light years away, in reasonable agreement with redshift-independent distance estimates of about 85 to 180 million the light years (the 108 million light year value associated with the HST images below is one of the most critical values). Given that and its apparent size of about 4.05 by 2.55 arcmin (from the images below), the galaxy is about 125 to 130 thousand light years across if the HST distance is correct, or about 135 thousand light years across if the "Hubble Flow" distance is correct. NGC 4603 is associated with the Centaurus Cluster, one of the most massive clusters of galaxies in the nearby Universe; and at the time that the HST image was taken (in 1999) it was the most distant galaxy in which Cepheid variable stars had been used to obtain a reasonably accurate estimate of its distance. Observations of Cepheid variables are one of the most important "steps" in the extragalactic distance scale, and determining the distances of Cepheids in the furthest possible galaxies by measuring the brightness and period of variability of those stars helps to improve our understanding of the Universe.
DSS image of region near spiral galaxy NGC 4603, also showing NGC 4601 and PGC 42460, which is sometimes called NGC 4603B
Above, a 12 arcmin wide DSS image centered on NGC 4603, also showing NGC 4601 and and PGC 42460
Below, a 3.5 by 4 arcmin wide image of the galaxy
(Image Credit & © Carnegie-Irvine Galaxy Survey; used by permission)
Carnegie-Irvine Galaxy Survey image of spiral galaxy NGC 4603
Below, a 1.8 by 2.6 arcmin wide image of the central part of the galaxy
(Image Credit Hubble Legacy Archive, Courtney Seligman)
HST image of spiral galaxy NGC 4603
Below, a 1.2 by 1.5 arcmin wide image of the core of the galaxy
(Image Credit NASA, Jeffrey Newman (Univ. of California at Berkeley))HST image of central part of spiral galaxy NGC 4603

PGC 42369 (= "NGC 4603A" = ESO 322-044)
Not an NGC object but listed here because sometimes called NGC 4603A
A magnitude 13.4 spiral galaxy (type SBc?) in
Centaurus (RA 12 39 36.9, Dec -40 44 24)
Physical Information: Apparent size 1.9 by 0.6 arcmin?

PGC 42460 (= PGC 579351 = ESO 322-048 = "NGC 4603B")
Not an NGC object but listed here because sometimes called NGC 4603B
A magnitude 14.7 spiral galaxy (type SBb?) in
Centaurus (RA 12 40 29.8, Dec -41 04 10)
Physical Information: Apparent size 1.4 by 0.3 arcmin?

PGC 42486 (= "NGC 4603C")
Not an NGC object but listed here since sometimes called NGC 4603C
A magnitude 13.0 lenticular galaxy (type S0?) in
Centaurus (RA 12 40 43.1, Dec -40 45 48)
Physical Information: Apparent size 1.7 by 0.4 arcmin?

PGC 42640 (= "NGC 4603D" = ESO 322-055)
Not an NGC object but listed here since sometimes called NGC 4603D
A magnitude 13.2 spiral galaxy (type SBcd?) in
Centaurus (RA 12 42 08.1, Dec -40 49 15)
Physical Information: Apparent size 1.5 by 1.1 arcmin?

NGC 4604 (=
NGC 4602 = PGC 42476, and not = PGC 42489)
Discovered (Apr 24, 1784) by William Herschel (and laer listed as NGC 4602)
Also observed (Feb 19, 1830) by John Herschel (and later listed as NGC 4602)
Also observed? (1883) by Christian Peters (and later listed as NGC 4604)
A magnitude 11.5 spiral galaxy (type SAB(rs)bc) in Virgo (RA 12 40 36.9, Dec -05 07 58)
Historical Identification: Per Dreyer, NGC 4604 (Peters, 1860 RA 12 33 32, NPD 94 22.6) has "no description". The position precesses to RA 12 40 44.8, Dec -05 08 46, only 2.1 arcmin east southeast of NGC 4602 and barely outside its souteastern outline (hardly surprising since their NGC positions differ by only 5 seconds of time and 0.8 arcmin of polar distance) and there is nothing else in the region that Peters could have possibly seen, so lacking a description to the contrary it seems certain that NGC 4604 is a duplicate observation of NGC 4602. However, for reasons almost beyond understanding the RC3 chose a galaxy (PGC 42489) 10 arcmin to the south as NGC 4604, and thanks to bad luck (namely, the fact that a 10 arcmin error could be thought of as a single-digit recording error), the misidentification has stuck (given the lack of a description even Corwin has accepted that suggestion). As a result, that object is discussed in the entry immediately below, albeit as a misidentification, rather than as the correct object.
Historical References: Per Steinicke, "There are no sources for three of Peters' discoveries (NGC 3492, NGC 4309 and NGC 4604). According to their positions, they fit well into the first list [Published in Copernicus I.]. Dreyer, who included all of these objects in the NGC, was probably informed by letter." It is hard to see why, if Peters provided no description of "his" object, Dreyer didn't presume that it was just another observation of NGC 4602, but there are many examples in the NGC/IC of obvious duplications that Dreyers (and his sources) failed to recognize; and since there is no description, there is no obvious reason why Peters' "Nova" should be considered to be anything other than a duplicate observation of NGC 4602.
Argument Against And For The Duplication: There is a caveat that might be raised about the simplicity of the conclusion in the previous paragraphs; namely, how do we know that Peters hadn't observed something else and simply misrecorded its position? His published papers represent a survey of objects he had observed over previous decades and marked on a map of the sky. When he finally got around to publishing his observations, he estimated their positions from their position on his map, and if an observation corresponded to an object in the GC he listed his observation as that object, and if not, he listed it as a Nova (in the age of nebular discovery, a nova meant something not previously observed, not necessarily an exploding star, as it does today). The vast majority of the objects in his published papers have General Catalog identifications assigned to them, so Peters obviously had a copy of the GC and should have seen that GC 3140 (now = NGC 4602) was near the "Nova" that became NGC 4604 (if his published position was correct), in which case he presumably had reason to think that his observation was of a different object. However, we know that in at least one case (GC 2911 = NGC 4348) he simply failed to notice the appropriate GC entry and listed his observation as a Nova, because he corrected that error in his first paper at the end of his second paper. Aside from that, when he wrote to Dreyer, if Peters thought that the object was not GC 3140 = NGC 4602, wouldn't he have written something to explain his reasoning (e.g., "near but not GC 3140")? And if he had, wouldn't Dreyer have noted that in the NGC (in some similar way) instead of "No description"? In my opinion the most obvious and probable conclusion is that in this case, as in the case of GC 2911, Peters simply failed to notice the corresponding GC entry and Dreyer failed to notice the similarity in position to that object. We can't go back in time and know the truth for certain, but it is certainly more reasonable to conclude that it was a simple oversight, rather than the less likely kind of mistake that led to assigning an object 10 arcmin from Peters' position (sometimes mistakenly stated as a 10 degree(!) error) to the NGC entry.
Physical Information: Given the essentially certain duplicate entry, see NGC 4602 for anything else.
SDSS image of region centered on the NGC position for NGC 4604, showing NGC 4602 to the upper right
Above, a 4 arcmin wide SDSS image centered on the NGC position of NGC 4604, also showing NGC 4602

PGC 42489 (almost certainly not =
NGC 4604)
Almost certainly not an NGC object but listed here since often misidentified as NGC 4604
A magnitude 13.8 irregular galaxy (type Im?) in Virgo (RA 12 40 45.2, Dec -05 18 12)
Historical (Mis)Identification: For some reason, RC3 listed this galaxy as NGC 4604, despite its being 10 arcmin from the NGC position for that object; but the NGC position is only a couple of arcmin from NGC 4602, so the far more reasonable conclusion is that NGC 4604 is not PGC 42489, but a duplicate entry of NGC 4602. As a result, this entry serves primarily as a warning against the misidentification, though as noted in the entry for NGC 4604 the actual identification will probably remain controversial, since there is no record of what Peters wrote to Dreyer, and we can't go back in time and read either their correspondence or their minds.
Physical Information: Apparent size 1.0 by 0.4 arcmin?

NGC 4605 (= PGC 42408)
Discovered (Mar 19, 1790) by
William Herschel
Also observed (Apr 14, 1831) by John Herschel
A magnitude spiral 10.3 galaxy (type SBc? pec) in Ursa Major (RA 12 39 59.3, Dec +61 36 33)
Historical Identification: Per Dreyer, NGC 4605 (= GC 3142 = JH 1381 = WH I 254, 1860 RA 12 33 45, NPD 27 37.2) is "bright, large, very much extended 118.6°, gradually a little brighter middle". The position precesses to RA 12 39 58.9, Dec +61 36 38, almost dead center on the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 5.9 by 2.4 arcmin?

NGC 4606 (= PGC 42516)
Discovered (Mar 15, 1784) by
William Herschel
Also observed (Apr 11, 1825) by John Herschel
A magnitude 11.8 spiral galaxy (type SBa?) in Virgo (RA 12 40 57.6, Dec +11 54 43)
Historical Identification: Per Dreyer, NGC 4606 (= GC 3143 = JH 1382 = WH III 43, 1860 RA 12 33 53, NPD 77 20.2) is "very faint, pretty small, extended, 2 or 3 very small (faint) stars involved". The position precesses to RA 12 40 56.7, Dec +11 53 39, right on the galaxy listed above, the description fits and the only thing near is accounted for by NGC 4607, so the identification is certain.
Physical Information: Apparent size 3.3 by 1.7 arcmin? Listed as a member (VCC 1859) of the Virgo Cluster.

NGC 4607 (= PGC 42544)
Discovered (Apr 24, 1854) by
R. J. Mitchell
A magnitude 12.8 spiral galaxy (type SBb?) in Virgo (RA 12 41 12.4, Dec +11 53 08)
Historical Identification: Per Dreyer, NGC 4607 (3rd Lord Rosse, 1860 RA 12 34 07, NPD 77 20) is "faint, much extended, 3 or 4 arcmin east of III 43", (WH) III 43 being NGC 4606. The position precesses to RA 12 41 10.6, Dec +11 55 52, about 2.7 arcmin north northwest of the galaxy listed above, but the description (including its relationship to NGC 4606) is a perfect fit, and there is nothing nearby save the galaxy accounted for by NGC 4606, so the identification is certain.
Discovery Notes: Although Dreyer credits the discovery to William Parsons, 3rd Earl of Rosse, he notes that many of Rosse's nebular discoveries were actually made by one of his assistants, in this case R. J. Mitchell.
Physical Information: Apparent size 2.9 by 0.7 arcmin? Listed as a member (VCC 1868) of the Virgo Cluster.

NGC 4608 (= PGC 42545)
Discovered (Mar 15, 1784) by
William Herschel
Also observed (Mar 13, 1826) by John Herschel
A magnitude 11.0 lenticular galaxy (type SB0?) in Virgo (RA 12 41 13.3, Dec +10 09 20)
Historical Identification: Per Dreyer, NGC 4608 (= GC 3144 = JH 1383 = WH II 69, 1860 RA 12 34 08, NPD 79 04.5) is "pretty bright, pretty large, round, pretty suddenly brighter middle, mottled but not resolved, 12th magnitude star 1 arcmin to northwest". The position precesses to RA 12 41 12.6, Dec +10 09 22, essentially dead center on the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 3.3 by 2.9 arcmin? Listed as a member (VCC 1869) of the Virgo Cluster.

NGC 4609 (= OCL 890 = ESO 095-SC014)
Discovered (May 12, 1826) by
James Dunlop
Also observed (Mar 8, 1837) by John Herschel
A magnitude 6.9 open cluster (type II1p) in Crux (RA 12 42 16.0, Dec -62 59 42)
Historical Identification: Per Dreyer, NGC 4609 (= GC 3145 = JH 3407, Dunlop #272, 1860 RA 12 34 13, NPD 152 12.1) is "a cluster, pretty large, pretty compressed, considerably extended, stars of 10th magnitude". The position precesses to RA 12 42 23.3, Dec -62 58 14, within the northeastern boundary of the cluster listed above, the description fits and there is nothing comparable nearby, so the identification is certain.
Physical Information: Apparent size 6.0 arcmin?

NGC 4610 (=
NGC 4470 = PGC 41189)
Discovered (Jan 23, 1784) by William Herschel (and later listed as NGC 4610)
Discovered (Dec 28, 1785) by William Herschel (and later listed as NGC 4470)
A magnitude spiral 12.1 galaxy (type Scd?) in Virgo (RA 12 29 37.8, Dec +07 49 27)
Historical Identification: Per Dreyer, NGC 4610 (= GC 3147 = WH II 19, 1860 RA 12 34 20, NPD 81 30.9) is "faint, very large (place uncertain)". The position precesses to RA 12 41 25.9, Dec +07 42 58, but the only thing near there is a galaxy (NGC 4623) which lies 45 seconds of time to the east and 2' 20" to the south, and that object does not fit the NGC description. However, none of that is of any importance, because in his Notes to The Scientific Papers of Sir William Herschel Dreyer states that there is nothing at the position of WH II 19, adds that Herschel misidentified the Messier object he used as a reference when observing II 19 (namely, he thought that the Messier object was M61, but it was actually M49); and by using the correct Messier object WH II 19 becomes identical to WH II 498, which is NGC 4470, as shown in the title for this entry. As a result, in his 1912 paper summarizing corrections to the NGC required by his work on the aforementioned volume, Dreyer writes "4610 to be struck out; II 19 = II 498 (= NGC 4470)." In other words, NGC 4610 has been known to be a misrecorded duplicate of NGC 4470 for more than a century.
Physical Information: Given the duplicate entries, see NGC 4470 for anything else.

NGC 4611 (=
IC 805 = PGC 42564)
Discovered (May 17, 1881) by Édouard Stephan (and later listed as NGC 4611)
Discovered (Apr 20, 1889) by Lewis Swift (and later listed as IC 805)
A magnitude 14.3 spiral galaxy (type SABbc?) in Coma Berenices (RA 12 41 25.4, Dec +13 43 46)
Historical Identification: Per Dreyer, NGC 4611 (Stephan list XII (#49), 1860 RA 12 34 23, NPD 75 30.1) is "considerably faint, small, a little extended, between 2 very faint stars". The position precesses to RA 12 41 25.5, Dec +13 43 46, right on the galaxy listed above and the description fits, so the identification is certain.
Physical Information: Based on a recessional velocity of 6120 km/sec, NGC 4611 is about 285 million light years away, in good agreement with redshift-independent distance estimates of 290 to 330 million light years. This is over 200 million light years beyond the Virgo Cluster, so although listed as a member of the cluster (VCC 1878) in the Virgo Cluster Catalog, it is merely in the same direction. Given that and its apparent size of 1.3 by 0.25 arcmin, it is about 110 thousand light years across.
SDSS image of region near spiral galaxy NGC 4611
Above, a 12 arcmin wide SDSS image centered on NGC 4611
Below, a 1.4 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy NGC 4611

NGC 4612 (= PGC 42574)
Discovered (Jan 23, 1784) by
William Herschel
Also observed (Dec 27, 1827) by John Herschel
A magnitude 11.5 lenticular galaxy (type SB0?) in Virgo (RA 12 41 32.8, Dec +07 18 54)
Historical Identification: Per Dreyer, NGC 4612 (= GC 3148 = GC 3174 = JH 1384 = WH II 148 = WH II 20, 1860 RA 12 34 27, NPD 81 54.9) is "pretty bright, small, round, pretty suddenly much brighter middle". The position precesses to RA 12 41 33.1, Dec +07 18 58, right on the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 2.7 by 2.0 arcmin? Listed as a member (VCC 1883) of the Virgo Cluster.

NGC 4613 (= PGC 42570)
Discovered (May 9, 1864) by
Heinrich d'Arrest
A magnitude 15.2 spiral galaxy (type Sa?) in Coma Berenices (RA 12 41 28.9, Dec +26 05 19)
Historical Identification: Per Dreyer, NGC 4613 (= GC 5665, d'Arrest, 1860 RA 12 34 34, NPD 63 09.1) is "very faint, small, a little extended, 1st of 3", the others being NGC 4614 and 4615. The position precesses to RA 12 41 28.9, Dec +26 04 46, only about 0.5 arcmin south of the galaxy listed above, the description is reasonable (though the galaxy is "extended" by a superposed star, that's not something that d'Arrest would have been able to tell), and the only other objects in the region are accounted for by the "2nd and 3rd of 3", so the identification is certain.
Physical Information: Apparent size 0.5 by 0.5 arcmin?
SDSS image of NGC 4613
Above, a 2.4 arcmin wide closeup of NGC 4613; see NGC 4615 for a wide-field view

NGC 4614 (= PGC 42573)
Discovered (May 9, 1864) by
Heinrich d'Arrest
Also observed (May 11, 1866) by Truman Safford
A magnitude 13.3 lenticular galaxy (type SB0/a?) in Coma Berenices (RA 12 41 31.5, Dec +26 02 34)
Historical Identification: Per Dreyer, NGC 4614 (= GC 5666, d'Arrest, 1860 RA 12 34 38, NPD 63 11.4) is "faint, small, round, 12th magnitude star to northwest, 2nd of 3", the others being NGC 4613 and 4615. The position precesses to RA 12 41 32.9, Dec +26 02 28, just off the southeastern end of the galaxy listed above, the description fits and the only other objects in the region are accounted for by the "1st and 3rd of 3", so the identification is certain.
Discovery Note: Safford's observations were not published until long after he made them, and Dreyer barely became aware of them in time to add them as an appendix to the NGC; so none of Safford's observations were shown in the actual NGC entries (some were shown in the first Index Catalog).
Physical Information: Apparent size 0.9 by 0.8 arcmin?
SDSS image of NGC 4614
Above, a 2.4 arcmin wide closeup of NGC 4614; see NGC 4615 for a wide-field view

NGC 4615 (= PGC 42584 =
Arp 34)
Discovered (May 9, 1864) by Heinrich d'Arrest
Also observed (May 11, 1866) by Truman Safford
A magnitude 13.1 spiral galaxy (type Scd?) in Coma Berenices (RA 12 41 37.3, Dec +26 04 22)
Historical Identification: Per Dreyer, NGC 4615 (= GC 5667, d'Arrest, 1860 RA 12 34 44, NPD 63 09.8) is "faint, pretty large, extended, 3rd of 3", the others being NGC 4613 and 4614. The position precesses to RA 12 41 38.8, Dec +26 04 05, within the curve of the southeastern arm of the galaxy listed above, the description fits and the only other objects in the region are accounted for by "the 1st and 2nd of 3", so the identification is certain.
Discovery Note: Safford's observations were not published until long after he made them, and Dreyer barely became aware of them in time to add them as an appendix to the NGC; so none of Safford's observations were shown in the actual NGC entries (some were shown in the first Index Catalog).
Physical Information: Used by the Arp Atlas as an example of an S- or integral-sign shaped spiral galaxy. Based on its recessional velocity of 4715 km/sec, NGC 4615 is about 210 million light years away. Given that and its apparent size of 1.6 by 0.7 arcmin, it is about 100 thousand light years across.
SDSS image of NGC 4615
Above, a 2.4 arcmin wide closeup of NGC 4615
Below, a 12 arcmin wide region centered on the galaxy; also shown are NGC 4613 and 4614
SDSS image of region near NGC 4615

NGC 4616 (= PGC 42662 = ESO 322-056)
Discovered (Jun 5, 1834) by
John Herschel
A magnitude 13.3 elliptical galaxy (type E0?) in Centaurus (RA 12 42 16.5, Dec -40 38 32)
Historical Identification: Per Dreyer, NGC 4616 (= GC 3149 = JH 3408, 1860 RA 12 34 45, NPD 129 54.2) is "extremely faint, very small, round, star attached on northeast, preceding (western) of 2", the other being NGC 4622. The position precesses to RA 12 42 21.8, Dec -40 40 19, about 2 arcmin southeast of the galaxy listed above, the description fits and the closest other object in the region is accounted for by NGC 4622, so the identification is certain.
Physical Information: Apparent size 0.9 by 0.9 arcmin?
Corwin lists an apparent companion (PGC 42667) at RA 12 42 17.9, Dec -40 39 29

NGC 4617 (= PGC 42530)
Discovered (Mar 9, 1788) by
William Herschel
A magnitude 13.2 spiral galaxy (type Sb?) in Canes Venatici (RA 12 41 05.9, Dec +50 23 36)
Historical Identification: Per Dreyer, NGC 4617 (= GC 3150 = WH II 744, 1860 RA 12 34 46, NPD 38 48.8) is "pretty faint, small, irregularly round, extremely mottled but not resolved". The position precesses to RA 12 41 18.4, Dec +50 25 05, about 2.5 arcmin northeast of the galaxy listed above (almost on top of the magnitude 9.3 star also northeast of the galaxy), and although the elongated nature of the galaxy in modern images isn't a very good fit to the description, it is sufficiently faint that Herschel almost certainly couldn't see that, and there is nothing else nearby, so the identification is reasonably certain. (NOTE TO SELF: GOTTLIEB'S OBSERVATION SHOULD CONFIRM THIS)
Physical Information: Apparent size 2.9 by 0.5 arcmin?

NGC 4618 (= PGC 42575 =
IC 3667 = Arp 23)
Discovered (Apr 9, 1787) by William Herschel (and later listed as NGC 4618)
Also observed (May 1, 1828) by John Herschel (and later listed as NGC 4618)
Discovered (Mar 21, 1903) by Max Wolf (and later listed as IC 3667)
A magnitude 10.8 spiral galaxy (type SB(rs)m? pec) in Canes Venatici (RA 12 41 32.5, Dec +41 09 03)
Historical Identification: Per Dreyer, NGC 4618 (= GC 3151 = GC 3152 = JH 1385 = WH I 178 = WH I 179, 1860 RA 12 34 50, NPD 48 04.8) is "bright, large, extended, much brighter middle, curved branch to north" (see the note about Vorontsov-Velyaminov below). The position precesses to RA 12 41 32.8, Dec +41 08 59, essentially dead center on the galaxy listed above, the description is a perfect fit and there is nothing comparable nearby, so the identification is certain.
Arp Atlas and Vorontsov-Velyaminov Usage: NGC 4618 is used by the Arp Atlas as an example of a one-armed spiral galaxy (without any note save its NGC designation). It was also used in the Vorontsov-Velyaminov catalog of interacting galaxies (as VV 73), presumably because in older glass-plate images the main body of the galaxy and its curved spiral arm look more like a pair of galaxies than a single galaxy. This may also be why William Herschel assigned it two catalog entries (WH I 178 and 179), leading to two entries in his son's General Catalog (GC), as noted in the NGC entry by Dreyer.
Physical Information: Based on a recessional velocity relative to the Cosmic Microwave Background radiation of 770 km/sec (and H0 = 70 km/sec/Mpc), NGC 4618 is about 35 million light years away, in fair agreement with redshift-independent distance estimates of about 20 to 25 million light years (the HST press release uses a distance of 21 million light years). Given that and its apparent size of about 4.0 by 3.2 arcmin (from the images below), the galaxy is about 40 thousand light years across. The galaxy is part of an interacting pair with NGC 4625, which see for a discussion of the results of that interaction, one of them undoubtedly being the large spiral arm to the southeast of NGC 4618.
SDSS image of region near NGC 4618, also known as Arp 23
Above, a 12 arcmin wide SDSS image centered on NGC 4618
Below, a 4 arcmin wide SDSS image of the galaxy
SDSS image of NGC 4618, also known as Arp 23
Below, a 3.4 arcmin wide HST image of the galaxy (Image Credit ESA/Hubble & NASA, I. Karachentsev)
HST image of NGC 4618, also known as Arp 23
Below, a 6 arcmin wide GALEX ultraviolet image of the galaxy
GALEX image of NGC 4618
Below, a 12 arcmin wide SDSS image showing the relative positions of NGC 4618 and 4625
SDSS image of region between spiral galaxy NGC 4618 and NGC 4625
Below, a ? arcmin wide image of the two galaxies (note the faint extended structure around NGC 4625)
(Image Credit Tom Bash and John Fox/Adam Block/AURA/NSF/NOAO)
NOAO image of spiral galaxy NGC 4618, also known as Arp 23, and NGC 4625

NGC 4619 (= PGC 42594)
Discovered (May 1, 1785) by
William Herschel
Also observed (Apr 27, 1827) by John Herschel
A magnitude 12.7 spiral galaxy (type SBb? pec) in Canes Venatici (RA 12 41 44.6, Dec +35 03 46)
Historical Identification: Per Dreyer, NGC 4619 (= GC 3154 = JH 1388 = WH II 411, 1860 RA 12 34 57, NPD 54 09.9) is "faint, pretty small, round, a little brighter middle, 8th or 9th magnitude star to east". The position precesses to RA 12 41 45.1, Dec +35 03 59, on the northeastern rim of the galaxy listed above, the description is a perfect fit and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 1.3 by 1.3 arcmin?

NGC 4620 (= PGC 42619)
Discovered (Mar 29, 1830) by
John Herschel
A magnitude 12.2 lenticular galaxy (type S0?) in Virgo (RA 12 41 59.3, Dec +12 56 34)
Historical Identification: Per Dreyer, NGC 4620 (= GC 3153 = JH 1387, 1860 RA 12 34 58, NPD 76 17.5) is "very faint, small, round, very gradually brighter middle". The position precesses to RA 12 42 00.9, Dec +12 56 23, on the southeastern rim of the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 1.8 by 1.5 arcmin? Listed as a member (VCC 1902) of the Virgo Cluster.

NGC 4621 (= PGC 42628 =
M59)
Discovered (Apr 11, 1779) by Johann Koehler
Discovered (Apr 15, 1779) by Charles Messier and recorded as M59
Also observed (Apr 10, 1825) by John Herschel
A magnitude 9.6 elliptical galaxy (type E5?) in Virgo (RA 12 42 02.3, Dec +11 38 49)
Historical Identification: Per Dreyer, NGC 4621 (= GC 3155 = JH 1386, M 59, 1860 RA 12 34 58, NPD 77 35.1) is "bright, pretty large, a little extended, very suddenly very much brighter middle, 2 stars to west". The position precesses to RA 12 42 01.6, Dec +11 38 47, almost dead center on the galaxy listed above, the description fits and there is nothing comparable nearby, so the identification is certain.
Physical Information: Apparent size 5.4 by 3.7 arcmin. Listed as a member (VCC 1903) of the Virgo Cluster of galaxies. Used by the de Vaucouleurs Atlas of Galaxy Types as an example of galaxy type E5.
SDSS image of elliptical galaxy NGC 4621, also known as M59
Above, a 7 arcmin wide closeup of NGC 4621
Below, a 12 arcmin wide region centered on the galaxy
SDSS image of region near elliptical galaxy NGC 4621, also known as M59

NGC 4622 (= PGC 42701 = ESO 322-057)
Discovered (Jun 5, 1834) by
John Herschel
A magnitude 12.5 spiral galaxy (type Sa?) in Centaurus (RA 12 42 37.6, Dec -40 44 39)
Historical Identification: Per Dreyer, NGC 4622 (= GC 3156 = JH 3409, 1860 RA 12 35 04, NPD 129 58.5) is "pretty faint, small, round, pretty suddenly a little brighter middle, following (eastern) of 2", the other being NGC 4616. The position precesses to RA 12 42 41.1, Dec -40 44 36, just off the eastern rim of the galaxy listed above, the description fits and there is nothing comparable nearby, so the identification is certain.
Physical Information: Apparent size 1.7 by 1.6 arcmin?

PGC 42845 (= ESO 322-064 = "NGC 4622A")
Not an NGC object but listed here because sometimes called NGC 4622A
A 13th-magnitude 13.2 lenticular galaxy (type E/SB0?) in
Centaurus (RA 12 43 49.1, Dec -40 42 52)
Physical Information: Apparent size 0.6 by 0.5 arcmin?

PGC 42852 (= ESO 322-064A = "NGC 4622B")
Not an NGC object but listed here because sometimes called NGC 4622B
A magnitude 14.2 lenticular galaxy (type S0?) in
Centaurus (RA 12 43 50.7, Dec -40 43 03)
Physical Information: Apparent size 0.6 by 0.5 arcmin?

NGC 4623 (= PGC 42647)
Discovered (Apr 13, 1784) by
William Herschel
Also observed (Apr 25, 1830) by John Herschel
A magnitude 12.3 lenticular galaxy (type SB0/a?) in Virgo (RA 12 42 10.7, Dec +07 40 37)
Historical Identification: Per Dreyer, NGC 4623 (= GC 3157 = JH 1389 = WH II 149, 1860 RA 12 35 04, NPD 81 33.9) is "considerably faint, pretty large, extended, pretty suddenly a little brighter middle, mottled but not resolved". The position precesses to RA 12 42 09.8, Dec +07 39 59, barely southwest of the southern end of the galaxy listed above, the description is a perfect fit and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 2.2 by 0.7 arcmin? Listed as a member (VCC 1913) of the Virgo Cluster.

NGC 4624 (=
NGC 4664 = NGC 4665 = PGC 42970)
Discovered (Feb 23, 1784) by William Herschel (and later listed as NGC 4664)
Discovered (1786) by William Herschel (and later listed as NGC 4665)
Discovered (Apr 9, 1828) by John Herschel (and later listed as NGC 4624)
A magnitude 10.5 lenticular galaxy (type SB0/a?) in Virgo (RA 12 45 06.0, Dec +03 03 21)
Historical Identification: Per Dreyer, NGC 4624 (= GC 3158 = JH 1390, 1860 RA 12 35 07, NPD 86 10.3) is "bright, extended". The position precesses to RA 12 42 15.4, Dec +03 03 36, but there is nothing there. However, although not noted in the GC or NGC, in his original 1833 paper Herschel writes "RA ill-observed", so a search for something to the east or west of his position might reveal what he actually saw. Per Corwin, the most obvious candidate is NGC 4664 (= NGC 4665), the first galaxy to the east of Herschel's position, as shown in the title of this entry. That galaxy is also "bright, extended" (though that's not exactly how Herschel described it, he did state that it was "pretty bright" in the case of NGC 4664, and "bright" in the case of NGC 4665) and although it lies about 3 minutes of time to the east, it has almost exactly the same declination as Herschel's measurement, so it is essentially certain that NGC 4624 is simply an "ill-observed" record of the galaxy listed above.
Discovery Note: Per Corwin, some consideration has been given to the idea that NGC 4624 might be an ill-observed record of NGC 4600; but that not only lies over 5 minutes of time to the west but also 4 arcmin to the north of the NGC position, and is described as "faint, small, round", which is nothing like the description of NGC 4624. So that suggestion is undoubtedly wrong.
Physical Information: Given the duplicate entry, see NGC 4664 for anything else.

NGC 4625 (=
IC 3675 = PGC 42607)
Discovered (Apr 9, 1787) by William Herschel (and later listed as NGC 4625)
Also observed (May 1, 1828) by John Herschel (and later listed as NGC 4625)
Discovered (Mar 21, 1903) by Max Wolf (and later listed as IC 3675)
A magnitude 12.4 spiral galaxy (type SAB(rs)m pec) in Canes Venatici (RA 12 41 52.7, Dec +41 16 26)
Historical Identification: Per Dreyer, NGC 4625 (= GC 3160 = JH 1392 = WH II 660, 1860 RA 12 35 10, NPD 47 57.0) is "pretty faint, small, round". The position precesses to RA 12 41 52.4, Dec +41 16 53, on the northern rim of the galaxy listed above, the description fits and the only thing nearby is accounted for by NGC 4618, so the identification is certain.
Physical Information: Until recently, NGC 4625 was thought to be a rather ordinary spiral galaxy; but a few years ago it was discovered that its interaction with NGC 4618 has created extended spiral arms around NGC 4625, so sparsely populated that they are barely noticeable in visible light, but stand out in ultraviolet images due to the intense radiation of their very hot young stars. In the "normal" visible light images below, there is only the faintest hint of the extensive spiral structure which lies beyond what appears to be the entire galaxy, although digitally stretching the visible-light image brightness shows fainter structure at the expense of detail in the brighter regions. GALEX ultraviolet images even more clearly show the extended structure, and adding radio imaging to the mix shows that both galaxies are surrounded by immense clouds of cool hydrogen gas which completely fill the region between and around the pair. (Note: This "invisible" spectacle is not an example of so-called "dark matter", which cannot be seen with any kind of radiation, visible or otherwise.) The 600 km/sec recessional velocity of NGC 4625 is too small, in comparison to peculiar (non-Hubble-expansion) velocities, to provide a reliable distance estimate, but is in good agreement with a redshift-independent distance estimate of 27 to 30 million light years. Given that and its apparent size of 1.25 by 1.2 arcmin, the main body of NGC 4625 is only about 10 thousand light years across; but the outer structure is about 6 by 5 arcmin, which corresponds to about 45 thousand light years.
SDSS image of region near NGC 4625
Above, a 12 arcmin wide SDSS image centered on NGC 4625
Below, a 3 arcmin wide SDSS image of the galaxy
SDSS image of NGC 4625
Below, a 6 arcmin wide GALEX ultraviolet image of the galaxy
GALEX image of NGC 4625
Below, a 12 arcmin wide SDSS image showing the relative positions of NGC 4618 and 4625

Below, a more detailed image of the two galaxies (note the faint extended structure around NGC 4625)
(Image Credit Tom Bash and John Fox/Adam Block/AURA/NSF/NOAO)
NOAO image of NGC 4618, also known as Arp 23, and NGC 4625
Below, an enhanced version of the above image shows part of the outer structure of NGC 4625
(Image Credit Tom Bash and John Fox/Adam Block/AURA/NSF/NOAO; digital reprocessing by Courtney Seligman)
NOAO image of NGC 4618 and 4625, digitally stretched to show the extended structure of NGC 4625
Below, a multispectral (and of necessity, false-color) image of NGC 4625 and its companion, NGC 4618, combines radio imaging of cool hydrogen gas (in purple) with a visible light image (in red) and near and far ultraviolet radiation (in green and blue, respectively). (Image Credit: NASA/JPL-Caltech, Carnegie Observatories, WSRT, Planetary Photojournal)
Multispectral image of NGC 4618 and 4625
Below, a 1.5 by 2.5 arcmin wide HST image of NGC 4625
(Image Credit ESA/Hubble & NASA; North is on the right to allow for more detail)
HST image of spiral galaxy 4625

NGC 4626 (= PGC 42680)
Discovered (Mar 20, 1789) by
William Herschel
Also observed (Apr 16, 1828) by John Herschel
A magnitude 13.4 spiral galaxy (type Sbc?) in Virgo (RA 12 42 25.4, Dec -07 02 39)
Historical Identification: Per Dreyer, NGC 4626 (= GC 3161 = JH 1393 = JH 3410 = WH II 772, 1860 RA 12 35 10, NPD 96 16.2) is "very faint, considerably small, a little extended, gradually a little brighter middle". The position precesses to RA 12 42 24.0, Dec -07 02 18, less than half an arcmin northwest of the galaxy listed above, the description fits and there is nothing else nearby save for the galaxy accounted for by NGC 4628, so the identification is certain.
Physical Information: Apparent size 1.4 by 0.5 arcmin?

NGC 4627 (= PGC 42620, and with
NGC 4631 = Arp 281)
Discovered (Mar 20, 1787) by William Herschel
Also observed (Apr 29, 1827) by John Herschel
A magnitude 12.4 elliptical galaxy (type E4 pec) in Canes Venatici (RA 12 41 59.7, Dec +32 34 26)
Historical Identification: Per Dreyer, NGC 4627 (= GC 3159 = JH 1391 = WH II 659, 1860 RA 12 35 11, NPD 56 39.1) is "faint, small, round, northwestern of 2", the other being NGC 4631. The position precesses to RA 12 42 00.9, Dec +32 34 47, about 0.5 arcmin northeast of the center of the galaxy, but well within its outline, and it is northwest of its companion (which see for wide-field images), so the identification is certain.
Use By The Arp Atlas: With NGC 4631, used by the Arp Atlas as an example of a galaxy with infall and attraction. (ADD ARP NOTES?)
Physical Information: Based on a recessional velocity of 540 km/sec, NGC 4627 is about 25 million light years away. For such a small recessional velocity, peculiar (non-Hubble expansion) velocities could be a large part of the motion, leading to a poor result; but as it happens, the calculated distance is in good agreement with a redshift-independent distance estimate of 30 million light years. Given that and the galaxy's apparent size of 2.6 by 1.8 arcmin, NGC 4627 is about 25 thousand light years across.
SDSS image of NGC 4627 and part of NGC 4631
Above, a 3 arcmin wide closeup of NGC 4627 and part of its much larger companion, NGC 4631


NGC 4628 (= PGC 42681)
Discovered (Mar 20, 1789) by
William Herschel
Also observed (Apr 16, 1828) by John Herschel
A magnitude 13.5 spiral galaxy (type Sb?) in Virgo (RA 12 42 25.3, Dec -06 58 16)
Historical Identification: Per Dreyer, NGC 4628 (= GC 3162 = JH 1394 = JH 3411 = WH II 773, 1860 RA 12 35 11, NPD 96 11.4) is "considerably faint, small, extended, gradually brighter middle". The position precesses to RA 12 42 24.9, Dec -06 57 30, only 0.8 arcmin north northeast of the galaxy listed above, the description fits, and the only other object in the region is accounted for by NGC 4626, so the identification is certain.
Physical Information: Apparent size 1.7 by 0.5 arcmin?

(ALMOST CERTAINLY LOST OR NONEXISTENT)
NGC 4629 (almost certainly not =
PGC 42692)
Recorded (Feb 19, 1863) by Heinrich d'Arrest
Almost certainly a lost or nonexistent object in Virgo (RA 12 42 32.1, Dec -01 48 18), but
Usually (mis?)identified as a magnitude 13.2 spiral galaxy (type Sm?) at RA 12 42 32.7, Dec -01 21 03
Historical Identification: Per Dreyer, NGC 4629 (= GC 3163, d'Arrest, 1860 RA 12 35 21, NPD 91 02.2) is "pretty bright, pretty large, extended, a little brighter middle, ? [= possibly?] bi-nuclear". The position precesses to RA 12 42 32.1, Dec -01 48 18, but there is absolutely nothing anywhere near there. Rather oddly, there seems to be little or no discussion of this problem, and the commonly accepted identification (namely, the galaxy listed above) appears to have been chosen simply because it is roughly half a degree (30 arcmin) due north of the NGC position, and that kind of error is not as uncommon as might have been hoped. However, the galaxy listed above is neither bright nor large, and would have almost certainly been described by d'Arrest as very faint, and very or pretty small (as does Steve Gottlieb, in his visual observations of NGC objects). PGC 42692 was obviously chosen as NGC 4629 not because it was an appropriate choice, but simply because it was the closest thing to the NGC position that could be explained by a "simple" error in the position; and is almost certainly not what d'Arrest observed. As a result, I have chosen to describe NGC 4629 as lost or nonexistent above, and once I have had a chance to consult with other experts on the topic will probably deal with PGC 42692 as a supplementary entry.
Discovery Note: After a search of the region to the east and west of d'Arrest's position yielded no result, it occurred to me that in some cases (such as Baxendell's Unphotographable Nebula), a "ghost" image produced by light from a nearby bright star bouncing off the inside of the telescope tube can appear to be a nebula; though whether it would appear to be pretty bright and large is another matter. In any event, the position of gamma Virginis, a magnitude 3.5 star, could explain the production of such a ghost image in telescopes examining the region near d'Arrest's supposed nebula; so the possibility that NGC 4629 is simply nonexistent cannot be ignored.
Physical Information: PGC 42692 Apparent size 1.1 by 0.8 arcmin? Not bi-nuclear, but certainly a messy-looking object, whence its type

NGC 4630 (= PGC 42688)
Discovered (Feb 2, 1786) by
William Herschel
Also observed (Apr 7, 1828) by John Herschel
A magnitude 12.6 irregular galaxy (type IBm?) in Virgo (RA 12 42 31.4, Dec +03 57 30)
Historical Identification: Per Dreyer, NGC 4630 (= GC 3164 = JH 1395 = WH II 532, 1860 RA 12 35 22, NPD 85 16.4) is "considerably faint, small, round, a little brighter middle". The position precesses to RA 12 42 29.9, Dec +03 57 30, within the western outline of the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 1.7 by 1.2 arcmin? Listed as a member (VCC 1923) of the Virgo Cluster.

NGC 4631 (= PGC 42637, and with
NGC 4627 = Arp 281), The Whale Galaxy
Discovered (Mar 20, 1787) by William Herschel
Also observed (Apr 29, 1827) by John Herschel
A magnitude 9.2 spiral galaxy (type SB(s)d) in Canes Venatici (RA 12 42 07.9, Dec +32 32 23)
Historical Identification: Per Dreyer, NGC 4631 (= GC 3165 = JH 1397 = WH V 42, 1860 RA 12 35 22, NPD 56 40.9) is "a remarkable object, very bright, very large, extremely extended 70°±, brighter middle and nucleus, 12th magnitude star attached on north". The position precesses to RA 12 42 11.9, Dec +32 33 06, a little over 1 arcmin to the northeast of the center of the galaxy, but well within the outline of the "very large" galaxy, which matches Herschel's description in every respect; so the identification is certain.
Use By The Arp Atlas: With NGC 4627, used by the Arp Atlas as an example of a galaxy with infall and attraction. (ADD ARP NOTES?)
Physical Information: Based on a recessional velocity of 605 km/sec, NGC 4631 is about 28 million light years away. Given the small radial velocity, peculiar (non-Hubble expansion) velocities could substantially effect the quality of the result; but as it happens, the distance is in reasonable agreement with redshift-independent distance estimates of 18 to 24 million light years. Assuming a distance of about 25 million light years, the galaxy's apparent size of 15.5 by 2.7 arcmins corresponds to about 120 thousand light years. The galaxy is a gravitationally bound companion of the dwarf elliptical NGC 4627, which lies just above it, and of NGC 4656, which lies about half a degree to the southeast, and depending upon its distance from us, could be within half a million light years of its neighbor.
SDSS image of NGC 4631 and 4627
Above, an 18 arcmin wide "closeup" of NGC 4631 and its nearby companion, NGC 4627
Below, a "thumbnail" view of a very large HST composite image of NGC 4631
(Image Credit: Hubble Legacy Archive, ESA, NASA, Nikolaus Sulzenauer apod100517)
Thumbnail view of HST image of NGC 4631; click here to view a much larger version
Below, a 45 arcmin wide region between NGC 4631 and NGC 4656
SDSS image of region between NGC 4631 and 4656

NGC 4632 (= PGC 42689)
Discovered (Feb 22, 1784) by
William Herschel
Also observed (Apr 14, 1828) by John Herschel
A magnitude 11.7 spiral galaxy (type Sc?) in Virgo (RA 12 42 32.0, Dec -00 04 57)
Historical Identification: Per Dreyer, NGC 4632 (= GC 3166 = JH 1396 = WH I 14, 1860 RA 12 35 24, NPD 89 18.9) is "pretty bright, large, extended 45°±". The position precesses to RA 12 42 34.1, Dec -00 05 00, on the eastern rim of the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 3.0 by 1.2 arcmin?

NGC 4633 (=
IC 3688 = PGC 42699)
Discovered (Apr 27, 1887) by Edward Swift (and later listed as NGC 4633)
Discovered (Nov 23, 1900) by Arnold Schwassmann (and later listed as IC 3688)
A magnitude 13.1 spiral galaxy (type SBd?) in Coma Berenices (RA 12 42 37.4, Dec +14 21 26)
Historical Identification: Per Dreyer, NGC 4633 (Swift list VI (#46), 1860 RA 12 35 24, NPD 74 51.5) is "most extremely faint, pretty small, faint star close to west, III 603 to south", (WH) III 603 being NGC 4634. The position precesses to RA 12 42 26.0, Dec +14 22 24, about 2.8 arcmin west northwest of the galaxy listed above, but the description fits, including the position of the galaxy to its south, so the identification is certain.
Discovery Note: Although Dreyer's entry does not indicate which Swift was the observer, Lewis Swift's paper states that the observer was his son, Edward.
Physical Information: Apparent size 2.0 by 0.9 arcmin? Listed as a member (VCC 1929) of the Virgo Cluster. In the same field of view as NGC 4634.

NGC 4634 (= PGC 42707)
Discovered (Jan 14, 1787) by
William Herschel
Also observed (Apr 23, 1832) by John Herschel
A magnitude 12.4 spiral galaxy (type SBc?) in Coma Berenices (RA 12 42 40.9, Dec +14 17 44)
Historical Identification: Per Dreyer, NGC 4634 (= GC 3167 = JH 1398 = WH III 603, 1860 RA 12 35 39, NPD 74 56.0) is "very faint, large, much extended 135°±, very gradually brighter middle". The position precesses to RA 12 42 40.9, Dec +14 17 55, almost dead center on the galaxy listed above, the description is a perfect fit and the only other object in the region is accounted for by NGC 4633, so the identification is certain.
Physical Information: Apparent size 2.9 by 0.9 arcmin? Listed as a member (VCC 1932) of the Virgo Cluster. In the same field of view as NGC 4633.

NGC 4635 (= PGC 42704)
Discovered (Mar 23, 1827) by
John Herschel
A magnitude 12.6 spiral galaxy (type SBcd?) in Coma Berenices (RA 12 42 39.2, Dec +19 56 43)
Historical Identification: Per Dreyer, NGC 4635 (= GC 3168 = JH 1400, 1860 RA 12 35 40, NPD 69 17.5) is "very faint, large, very gradually a little brighter middle". The position precesses to RA 12 42 38.5, Dec +19 56 25, on the southwestern rim of the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 1.9 by 1.4 arcmin?

NGC 4636 (= PGC 42734)
Discovered (Feb 23, 1784) by
William Herschel
Also observed (Apr 9, 1828) by John Herschel
A magnitude 9.5 elliptical galaxy (type E2?) in Virgo (RA 12 42 49.9, Dec +02 41 16)
Historical Identification: Per Dreyer, NGC 4636 (= GC 3169 = GC 3170 = JH 1399 = JH 1401 = WH II 38, 1860 RA 12 35 41, NPD 86 32.7) is "bright, large, irregularly round, very gradually very much brighter middle, mottled but not resolved". The position precesses to RA 12 42 49.6, Dec +02 41 13, dead center on the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 5.9 by 4.6 arcmin? Listed as a member (VCC 1939) of the Virgo Cluster.

NGC 4637 (= PGC 42744)
Discovered (Mar 1, 1854) by
R. J. Mitchell
Also observed (Apr 13, 1866) by Hermann Schultz
Not observed (Sep 8, 1900) by Arnold Schwassmann
A magnitude 13.9 lenticular galaxy (type S0?) in Virgo (RA 12 42 54.1, Dec +11 26 18)
Historical Identification: Per Dreyer, NGC 4637 (= GC 3172, 3rd Lord Rosse, 1860 RA 12 35 43±, NPD 77 47±) "Makes a double nebula with h 1402 (?)", (JH) 1402 being NGC 4638. The position precesses to RA 12 42 46.6, Dec +11 26 55, on the northern rim of the much brighter galaxy to the west of the galaxy listed above, which is the aforementioned NGC 4638, but since the NGC position is obviously uncertain (as indicated by the ± signs), the main question is not which galaxy best corresponds to the position, but which of the two best corresponds to the description for NGC 4637. And since (as discussed below and in the entry for that galaxy) NGC 4638 is described as "considerably bright" by Schwassmann, whose precise position falls right on that galaxy, there can be no question that the galaxy that makes a double nebula with h 1402 is the one listed above, and the identification must be considered certain, despite the considerable confusion caused by Schwassmann's choosing the wrong NGC designation for his observation.
Discovery Note (1): Although Dreyer credits the discovery to William Parsons, 3rd Earl of Rosse, he notes that many of Rosse's nebular discoveries were actually made by one of his assistants, in this case R. J. Mitchell.
Discovery Note (2): In the second IC Dreyer adds "4637 SN. (= Schwassmnn): -- considerably bright, small, like a 10th magnitude star; place agrees," but there is a serious problem with this statement, in that it actually refers to NGC 4638, not 4637, as Schwassmann's position and description both fit the brighter of the two galaxies, not the fainter one (which 4637 is, by nearly 3 magnitudes). As a result I have mostly ignored Schwassmann's supposed observation of NGC 4637 in the Historical Identification for this entry, and moved it to the entry for NGC 4638.
Discovery Note (3): Corwin notes that the Herschels' observations of NGC 4638 were compared to one of the Messier Catalog galaxies, and that there was considerable confusion in historical times as to which Messier object they were using (as in the case of NGC 4610); as a result, several observers may have thought they were observing was the nebula that later became NGC 4637, but were actually observing a completely different object (NGC 4647), in which case that galaxy could be equated with NGC 4637. However, after mentioning that idea Corwin assigns it to the rubbish bin, so though mentioning it here for purposes of completeness, I also recommend dismissing it. However, it does explain why Schultz is mentioned in the list of observers, as Corwin feels that only he and Mitchell actually observed the faint companion to the east of NGC 4638.
Physical Information: Apparent size 1.2 by 0.5 arcmin? Listed as a member (VCC 1945) of the Virgo Cluster.

NGC 4638 (=
NGC 4667 = PGC 42728)
Discovered (Mar 15, 1784) by William Herschel (and later listed as NGC 4638)
Also observed (Apr 11, 1825) by John Herschel (and later listed as NGC 4638)
Also observed (Sep 8, 1900) by Arnold Schwassmann (while listed as NGC 4638)
Discovered (Mar 23, 1830) by John Herschel (and later listed as NGC 4667)
A magnitude 11.2 lenticular galaxy (type E/S0?) in Virgo (RA 12 42 47.4, Dec +11 26 33)
Historical Identification: Per Dreyer, NGC 4638 (= GC 3171 = JH 1402 = WH II 70 = WH II 176, 1860 RA 12 35 44, NPD 77 47.4) is "faint, round, gradually brighter middle".
Discovery Note: As noted above, Arnold Schwassmann observed this object on Sep 8, 1900 (date of observation provided by Steinicke), but he misidentified it as NGC 4637 (admittedly tentatively, by putting the identification in parentheses), so Dreyer posted his observation ("considerably bright, small, like a 10th-magnitude star; place agrees") as if it belonged to NGC 4637 in his notes for the second IC. But Schwassmann's position (1900 RA 12 37 44.54, Dec +11 59 26.5) precesses to RA 12 42 47.1, Dec +11 26 33, dead center on NGC 4638, and his description is a far better fit for NGC 4638 than 4637, so there is no doubt that what he observed was not NGC 4637, but NGC 4638, hence my moving his observation from the fainter galaxy to the brighter one.
Physical Information: Apparent size 2.2 by 1.4 arcmin? Listed as a member (VCC 1938) of the Virgo Cluster.

NGC 4639 (= PGC 42741)
Discovered (Apr 12, 1784) by
William Herschel
Also observed (Mar 29, 1830) by John Herschel
A magnitude 11.5 spiral galaxy (type SBbc?) in Virgo (RA 12 42 52.4, Dec +13 15 27)
Historical Identification: Per Dreyer, NGC 4639 (= GC 3173 = JH 1403 = WH II 125, 1860 RA 12 35 49, NPD 75 58.7) is "pretty bright, small, extended, mottled but not resolved, 12th magnitude star 1 arcmin to southeast".
Physical Information: Apparent size 2.9 by 2.0 arcmin? Listed as a member (VCC 1943) of the Virgo Cluster.
Corwin lists an apparent companion (PGC 42710) at RA 12 42 40.8, Dec +13 16 01

NGC 4640 (= PGC 42753)
Discovered (Apr 17, 1887) by
Lewis Swift
A magnitude 13.5 spiral galaxy (type SB??) in Virgo (RA 12 42 57.8, Dec +12 17 13)
Historical Identification: Per Dreyer, NGC 4640 (Swift list VI (#47), 1860 RA 12 35 54, NPD 76 58.1) is "extremely faint, pretty large, a little extended, star near to west".
Physical Information: Apparent size 1.4 by 0.8 arcmin? Listed as a member (VCC 1949) of the Virgo Cluster.

PGC 214021 (= "NGC 4640B")
Not an NGC object but listed here because sometimes called NGC 4640B
A magnitude 16.2 lenticular galaxy (type S0?) in
Virgo (RA 12 43 01.5, Dec +12 17 06)
Physical Information: Apparent size 0.2 by 0.1 arcmin? Approximately ten times further away than NGC 4640, so merely an optical companion.

NGC 4641 (= PGC 42769)
Discovered (Apr 17, 1887) by
Lewis Swift
A magnitude 13.2 lenticular galaxy (type S0?) in Virgo (RA 12 43 07.7, Dec +12 03 03)
Historical Identification: Per Dreyer, NGC 4641 (Swift list VI (#48), 1860 RA 12 35 58, NPD 77 11.1) is "extremely faint, pretty large, round, faint star near to east".
Physical Information: Apparent size 1.2 by 1.0 arcmin? Listed as a member (VCC 1955) of the Virgo Cluster.

NGC 4642 (= PGC 42791)
Discovered (Jan 1, 1786) by
William Herschel
A magnitude 12.9 spiral galaxy (type Sbc?) in Virgo (RA 12 43 17.8, Dec -00 38 40)
Historical Identification: Per Dreyer, NGC 4642 (= GC 3175 = WH III 494, 1860 RA 12 36 07, NPD 89 53.5) is "very faint, considerably small, extended".
Physical Information: Apparent size 1.9 by 0.5 arcmin?

NGC 4643 (= PGC 42797)
Discovered (Jan 24, 1784) by
William Herschel
Also observed (Apr 10, 1828) by John Herschel
A magnitude 10.8 lenticular galaxy (type SB0/a?) in Virgo (RA 12 43 20.1, Dec +01 58 42)
Historical Identification: Per Dreyer, NGC 4643 (= GC 3176 = JH 1404 = WH I 10, 1860 RA 12 36 11, NPD 87 15.3) is "considerably bright, pretty small, a little extended, much brighter middle".
Physical Information: Apparent size 3.1 by 2.5 arcmin?

NGC 4644 (= PGC 42708)
Discovered (Apr 14, 1789) by
William Herschel
Also observed (May 4, 1831) by John Herschel
A magnitude 13.9 spiral galaxy (type SBb? pec) in Ursa Major (RA 12 42 42.7, Dec +55 08 44)
Historical Identification: Per Dreyer, NGC 4644 (= GC 3177 = JH 1406 = WH II 794, 1, 1860 RA 12 36 18, NPD 34 04.4) is "very faint, small, round, gradually brighter middle" (see Discovery Note).
Discovery Note: William Herschel made two observations of what he called II 794, but his son John correctly decided that the two observations were of different objects, and renumbered them as II 794, 1 (later = NGC 4644) and II 794, 2 (later = NGC 4646). When Dreyer worked on the third catalog of galaxies and clusters in The Scientific Papers of Sir William Herschel he revised these designations by assigning II 794 to NGC 4644 and renumbering II 794, 2 (= NGC 4646) as II 910. As a result, in the entry for NGC 4646 you will see Dreyer's comment in his 1912 summary of corrections to the NGC that he had renumbered William Herschel's observation.
Physical Information: Apparent size 1.6 by 0.5 arcmin?

PGC 42725 (= "NGC 4644B")
Not an NGC object but listed here because sometimes called NGC 4644B
A magnitude 15.1 spiral galaxy (type Sc?) in
Ursa Major (RA 12 42 52.6, Dec +55 08 45)
Physical Information: Apparent size 0.9 by 0.2 arcmin? At about the same distance as NGC 4644, so probably a physical companion.

NGC 4645 (= PGC 42879 = ESO 322-066)
Discovered (Jun 8, 1834) by
John Herschel
A magnitude 11.8 elliptical galaxy (type E4?) in Centaurus (RA 12 44 10.0, Dec -41 45 00)
Historical Identification: Per Dreyer, NGC 4645 (= GC 3178 = JH 3412, 1860 RA 12 36 22, NPD 130 58.8) is "pretty bright, small, pretty suddenly brighter middle".
Physical Information: Apparent size 2.2 by 1.4 arcmin?

PGC 42764 (= ESO 322-059 = "NGC 4645A")
Not an NGC object but listed here because sometimes called NGC 4645A
A magnitude 11.1 lenticular galaxy (type SB0?) in
Centaurus (RA 12 43 05.6, Dec -41 21 32)
Physical Information: Apparent size 2.8 by 0.8 arcmin?
Corwin lists an apparent companion (2MASX J12430662-4120179 = PGC 3794695) at RA 12 43 06.6, Dec -41 20 18

PGC 42813 (= ESO 322-060= "NGC 4645B")
Not an NGC object but listed here because sometimes called NGC 4645B
A magnitude 12.1 lenticular galaxy (type SB0?) in
Centaurus (RA 12 43 31.2, Dec -41 21 44)
Physical Information: Apparent size 1.9 by 0.7 arcmin?

NGC 4646 (= PGC 42740)
Discovered (Apr 2, 1791) by
William Herschel
Also observed (May 4, 1831) by John Herschel
A magnitude 13.4 lenticular galaxy (type S0?) in Ursa Major (RA 12 42 52.1, Dec +54 51 22)
Historical Identification: Per Dreyer, NGC 4646 (= GC 3179 = JH 1407 = WH III 794, 2, 1860 RA 12 36 26, NPD 34 22.4) is "faint, small, 4 very small (faint) stars to southwest" (see Discovery Note).
Discovery Note: William Herschel made two observations of what he called II 794, but his son John correctly decided that the two observations were of different objects, and renumbered them as II 794, 1 (later = NGC 4644) and II 794, 2 (later = NGC 4646). When Dreyer worked on the third catalog of galaxies and clusters in The Scientific Papers of Sir William Herschel he revised these designations by assigning II 794 to NGC 4644 and renumbering II 794, 2 (= NGC 4646) as II 910. As a result, in his 1912 summary of corrections to the NGC Dreyer states "4646 has been numbered II 910."
Physical Information: Apparent size 1.0 by 0.8 arcmin?

NGC 4647 (= PGC 42816, and with
NGC 4649 = Arp 116)
Discovered (Mar 15, 1784) by William Herschel
Also observed (Mar 10, 1826) by John Herschel
A magnitude 11.3 spiral galaxy (type SBc?) in Virgo (RA 12 43 32.5, Dec +11 34 56)
Historical Identification: Per Dreyer, NGC 4647 (= GC 3180 = JH 1405 = WH III 44, 1860 RA 12 36 29, NPD 77 39.0) is "pretty faint, pretty large, a little extended 115°±, northwestern member of double nebula", the other being M60. (SEE NOTE ABOUT ID OF NGC 4637)
Physical Information: Apparent size 2.9 by 2.3 arcmin? Listed as a member (VCC 1972) of the Virgo Cluster. Used by the Arp Atlas as an example of an elliptical galaxy (NGC 4649, which see for images) close to and perturbing a spiral galaxy.
Corwin suggests that this is (although very unlikely) = NGC 4637 at RA 12 43 32.5, Dec +11 34 56

NGC 4648 (= PGC 42595)
Discovered (Nov 22, 1797) by
William Herschel
Also observed (Aug 21, 1828) by John Herschel
A magnitude 12.0 elliptical galaxy (type E3?) in Draco (RA 12 41 44.4, Dec +74 25 16)
Historical Identification: Per Dreyer, NGC 4648 (= GC 3181 = JH 1410 = WH I 274, 1860 RA 12 36 33, NPD 14 48.6) is "pretty bright, considerably small, round, gradually brighter middle, double star to west".
Physical Information: Apparent size 1.8 by 1.2 arcmin?

NGC 4649 (=
M60 = PGC 42831, and with NGC 4647 = Arp 116)
Discovered (Apr 11, 1779) by Johann Koehler
Discovered (Apr 12, 1779) by Barnaba Oriani
Observed/recorded (Apr 15, 1779) by Charles Messier as M60
Also observed (Apr 11, 1825) by John Herschel
A magnitude 8.8 elliptical galaxy (type E2?) in Virgo (RA 12 43 40.0, Dec +11 33 10)
Historical Identification: Per Dreyer, NGC 4649 (= GC 3182 = JH 1408, M 60, 1860 RA 12 36 37, NPD 77 40.8) is "very bright, pretty large, round, eastern of double nebula", the other member of the double nebula being NGC 4647.
Physical Information: M60 is a 120 thousand light year wide elliptical galaxy listed as a member (VCC 1978) of the Virgo Cluster, 60 million light years away. It is a massive galaxy, with thousands of globular clusters in addition to the trillions of stars in the galaxy itself. (Apparent size 7.6 by 6.2 arcmin.) Used by the de Vaucouleurs Atlas of Galaxy Types as an example of galaxy type E+2/SA0-. Used by the Arp Atlas as an example of an elliptical galaxy close to and perturbing a spiral galaxy (NGC 4647).
SDSS image of region near elliptical galaxy NGC 4649, also known as M60; also shown is NGC 4647
Above, a 12 arcmin wide region centered on NGC 4649; also shown is the more distant NGC 4647
Celestial Atlas
(NGC 4550 - 4599) ←NGC Objects: NGC 4600 - 4649→ (NGC 4650 - 4699)