Celestial Atlas
(NGC 3900 - 3949) ←NGC Objects: NGC 3950 - 3999 Link for sharing this page on Facebook→ (NGC 4000 - 4049)
Click here for Introductory Material
QuickLinks:
3950, 3951, 3952, 3953, 3954, 3955, 3956, 3957, 3958, 3959, 3960, 3961, 3962, 3963, 3964, 3965, 3966,
3967, 3968, 3969, 3970, 3971, 3972, 3973, 3974, 3975, 3976, 3977, 3978, 3979, 3980, 3981, 3982, 3983,
3984, 3985, 3986, 3987, 3988, 3989, 3990, 3991, 3992, 3993, 3994, 3995, 3996, 3997, 3998, 3999

Page last updated Sep 12, 2018
Added basic info (per Steinicke), Dreyer NGC entries
POSTED NEW IMAGES OF NGC 3981
WORKING: Checking discovery dates for supplementary observers noted by Dreyer

NGC 3950 (= PGC 37294)
Discovered (Apr 27, 1875) by
Lawrence Parsons, 4th Lord Rosse
A magnitude 15.7 elliptical galaxy (type E1?) in Ursa Major (RA 11 53 41.1, Dec +47 53 06)
Historical Identification: Per Dreyer, NGC 3950 (= GC 5591, 4th Lord Rosse, 1860 RA 11 46 22, NPD 41 19.4) is "extremely faint, 2.6 arcmin north of h 1009", "(JH) 1009" being NGC 3949. The position precesses to RA 11 53 41.4, Dec +47 53 53, only 0.8 arcmin north of the galaxy listed above, the description fits (the galaxy is only 1.6 arcmin north of NGC 3949, Lord Rosse's position and distance estimate being roughly an arcmin larger than the correct values) and there is nothing nearby that could possibly fit the description, so the identification is certain.
Physical Information: Based on a recessional velocity of 22365 km/sec, a straightforward calculation suggests that NGC 3950 is about 1.04 billion light years away. However, for objects at such a distance, we need to take the Universal expansion into account. Doing that shows that the galaxy was about 955 million light years away when the light by which we see it left the galaxy, about 990 million years ago (the difference between the two numbers being due to the expansion of the intervening space in that interval). Given that and its apparent size of 0.40 by 0.35 arcmin, the galaxy is about 110 thousand light years across.
SDSS image of NGC 3950
Above, a 2.4 arcmin wide closeup of NGC 3950 and the northern part of NGC 3949
Below, a 12 arcmin wide view centered on NGC 3949
SDSS image of region near NGC 3949 and 3950

NGC 3951
Discovered (Apr 10, 1785) by
William Herschel
Also observed (Mar 28, 1832) by John Herschel
A magnitude 13.6 spiral galaxy (type S?) in Leo (RA 11 53 41.3, Dec +23 22 56)
Historical Identification: Per Dreyer, NGC 3951 (= GC 2605 = JH 1010 = WH III 342, 1860 RA 11 46 22, NPD 65 49.5) is "very faint, considerably small, very little extended".
Physical Information:

NGC 3952 (=
IC 2972)
Discovered (Mar 11, 1787) by William Herschel (and later listed as NGC 3952)
Also observed (Mar 12, 1826) by John Herschel (and later listed as NGC 3952)
Discovered (Mar 23, 1895) by Lewis Swift (and later listed as IC 2972)
A magnitude 13.1 spiral galaxy (type Sm?) in Virgo (RA 11 53 40.1, Dec -03 59 50)
Historical Identification: Per Dreyer, NGC 3952 (= GC 2607 = JH 1012 = WH III 612, 1860 RA 11 46 28, NPD 93 13.4) is "considerably faint, considerably small, a little extended 90°±, brighter middle, mottled but not resolved".
Physical Information:

NGC 3953 (= PGC 37306)
Discovered (Mar 12, 1781) by
Pierre Méchain
Discovered (Apr 12, 1789) by William Herschel
Also observed (Feb 17, 1831) by John Herschel
A magnitude 10.1 spiral galaxy (type SB(r)bc?) in Ursa Major (RA 11 53 48.4, Dec +52 19 30)
Historical Identification: Per Dreyer, NGC 3953 (= GC 2606 = JH 1011 = WH V 45, 1860 RA 11 46 29, NPD 36 53.1) is "considerably bright, large, extended 0°±, very suddenly brighter middle and large mottled but not resolved nucleus". The position precesses to RA 11 53 49.8, Dec +52 20 11, on the northern rim of the nucleus of the galaxy listed above and well within its outline, the description fits and there is nothing else nearby, so the identification is certain.
Discovery Notes: Until 2006 it was thought that Méchain's observation was of what became NGC 3992 (which see for more information about Méchain's discovery), and neither the Herschels nor Dreyer were aware of the prior observation under any identification, causing the lack of any mention of the French astronomer in either NGC entry.
Physical Information: Based on a recessional velocity of 1050 km/sec, NGC 3953 is about 50 million light years away, in good agreement with redshift-independent distance estimates of 40 to 75 million light years. Given that and its apparent size of 6.6 by 3.1 arcmin, the galaxy is about 95 thousand light years across.
SDSS image of region near spiral galaxy NGC 3953
Above, a 12 arcmin wide SDSS image centered on NGC 3953

NGC 3954
Discovered (Apr 26, 1785) by
William Herschel
Also observed (Feb 24, 1827) by John Herschel
A magnitude 13.7 compact galaxy (type ?) in Leo (RA 11 53 41.7, Dec +20 52 57)
Historical Identification: Per Dreyer, NGC 3954 (= GC 2608 = JH 1013 = WH III 381, 1860 RA 11 46 30, NPD 68 20.7) is "extremely faint, round".
Physical Information:

NGC 3955
Discovered (Dec 21, 1786) by
William Herschel
A magnitude 12.0 lenticular galaxy (type S0/a?) in Crater (RA 11 53 57.2, Dec -23 09 52)
Historical Identification: Per Dreyer, NGC 3955 (= GC 2609 = WH II 623, 1860 RA 11 46 54, NPD 112 24.0) is "considerably faint, small, extended 170°±, a little brighter on the south".
Physical Information:

NGC 3956
Discovered (Mar 10, 1785) by
William Herschel
Also observed (Mar 23, 1835) by John Herschel
A magnitude 12.0 spiral galaxy (type SBc?) in Crater (RA 11 54 00.9, Dec -20 34 00)
Historical Identification: Per Dreyer, NGC 3956 (= GC 2610 = JH 3368 = WH III 290, 1860 RA 11 46 57, NPD 109 47.5) is "considerably faint, pretty large, pretty much extended 57°".
Physical Information:

NGC 3957 (=
IC 2965)
Discovered (Feb 7, 1785) by William Herschel (and later listed as NGC 3957)
Discovered (Feb 20, 1898) by Lewis Swift (and later listed as IC 2965)
A magnitude 11.8 lenticular galaxy (type S0/a?) in Crater (RA 11 54 01.5, Dec -19 34 08)
Historical Identification: Per Dreyer, NGC 3957 (= GC 2611 = WH II 294, 1860 RA 11 46 58, NPD 108 47.0) is "faint, small, extended, mottled but not resolved".
Physical Information:

NGC 3958
Discovered (Mar 18, 1790) by
William Herschel
Also observed (Feb 9, 1831) by John Herschel
A magnitude 13.0 spiral galaxy (type SBa?) in Ursa Major (RA 11 54 33.5, Dec +58 22 00)
Historical Identification: Per Dreyer, NGC 3958 (= GC 2612 = JH 1014 = WH II 833, 1860 RA 11 47 10, NPD 30 51.7) is "pretty faint, pretty small, pretty much extended, very gradually brighter middle".
Physical Information:

NGC 3959
Discovered (May 19, 1881) by
Wilhelm Tempel
A magnitude 13.7 spiral galaxy (type SBa?) in Crater (RA 11 54 37.6, Dec -07 45 23)
Historical Identification: Per Dreyer, NGC 3959 (Tempel list V (#11/12), 1860 RA 11 47 27, NPD 96 58.6) is "very faint, small, between 2 very faint stars".
Physical Information:

NGC 3960
Discovered (Apr 30, 1826) by
James Dunlop
Also observed (Apr 5, 1837) by John Herschel
A magnitude 8.3 open cluster (type I2m) in Centaurus (RA 11 50 33.1, Dec -55 40 35)
Historical Identification: Per Dreyer, NGC 3960 (= GC 2614 = JH 3369, Dunlop 349, 1860 RA 11 47 29, NPD 144 56.4) is "a cluster, pretty large, pretty rich, gradually pretty much brighter middle, stars 13th magnitude".
Physical Information:

NGC 3961
Discovered (Apr 7, 1793) by
William Herschel
A magnitude 13.5 spiral galaxy (type SBa?) in Draco (RA 11 54 57.5, Dec +69 19 47)
Historical Identification: Per Dreyer, NGC 3961 (= GC 2615 = WH III 905, 1860 RA 11 47 31, NPD 19 54.0) is "extremely faint, very small".
Physical Information:

NGC 3962
Discovered (Feb 8, 1785) by
William Herschel
Also observed (Mar 16, 1836) by John Herschel
A magnitude 10.7 elliptical galaxy (type E1?) in Crater (RA 11 54 39.8, Dec -13 58 29)
Historical Identification: Per Dreyer, NGC 3962 (= GC 2616 = JH 3370 = WH I 67, 1860 RA 11 47 33, NPD 103 11.8) is "considerably bright, pretty large, irregularly round, gradually much brighter middle, in a triangle with 2 stars".
Physical Information:

NGC 3963
Discovered (Mar 18, 1790) by
William Herschel
Also observed (Nov 19, 1829) by John Herschel
A magnitude 11.9 spiral galaxy (type SBbc?) in Ursa Major (RA 11 54 58.8, Dec +58 29 36)
Historical Identification: Per Dreyer, NGC 3963 (= GC 2613 = JH 1015 = WH IV 67, 1860 RA 11 47 37, NPD 30 43.9) is "pretty faint, considerably large, round, very gradually then suddenly brighter middle".
Physical Information:

NGC 3964
Discovered (Mar 30, 1827) by
John Herschel
A magnitude 14.0 lenticular galaxy (type S0?) in Leo (RA 11 54 53.4, Dec +28 15 46)
Historical Identification: Per Dreyer, NGC 3964 (= GC 2617 = JH 1016, 1860 RA 11 47 39, NPD 60 57.1) is "very faint, small, extended, 10th magnitude star attached on northeast".
Physical Information:

NGC 3965
Discovered (1886) by
Francis Leavenworth
A magnitude 15.7 spiral galaxy (type S?) in Crater (RA 11 54 23.1, Dec -10 51 59)
Historical Identification: Per Dreyer, NGC 3965 (Leavenworth list II (#452), 1860 RA 11 47 58, NPD 100 06.0) is "extremely faint, extremely small, round, brighter middle and nucleus, 9.5 magnitude star 4 arcmin to northwest".
Physical Information:

NGC 3966 (=
NGC 3986)
Discovered (Apr 29, 1827) by John Herschel (and later listed as NGC 3986)
Also observed (Mar 27, 1906) by Max Wolf (while listed as NGC 3986)
Discovered (May 8, 1864) by Heinrich d'Arrest (and later listed as NGC 3966)
A magnitude 12.7 lenticular galaxy (type S0/a?) in Ursa Major (RA 11 56 44.2, Dec +32 01 17)
Historical Identification: Per Dreyer, NGC 3966 (= GC 5592, d'Arrest, 1860 RA 11 47 59, NPD 57 01.5) is "faint, pretty large, a little extended, brighter middle, 12th magnitude star to west". The second IC lists a corrected RA (per Wolf list VIII) of 11 48 29, and notes that d'Arrest made only one observation. (Note: Wolf's paper states that NGC 4113 does not exist, but I do not see a reference to NGC 3966; either I missed it, or he communicated the fact to Dreyer directly.)
Physical Information:

NGC 3967
Discovered (May 19, 1881) by
Wilhelm Tempel
A magnitude 13.4 lenticular galaxy (type E/S0?) in Crater (RA 11 55 10.3, Dec -07 50 35)
Historical Identification: Per Dreyer, NGC 3967 (Temple list V (#13/14), 1860 RA 11 48 01, NPD 97 03.9) is "very faint, small, faint star close to west".
Physical Information:

NGC 3968
Discovered (Apr 17, 1784) by
William Herschel
Also observed (Mar 23, 1830) by John Herschel
A magnitude 11.8 spiral galaxy (type SBbc?) in Leo (RA 11 55 28.7, Dec +11 58 07)
Historical Identification: Per Dreyer, NGC 3968 (= GC 2621 = JH 1018 = WH II 162, 1860 RA 11 48 15, NPD 77 15.1) is "pretty bright, large, irregularly round, brighter middle, 10th magnitude star 3 arcmin distant at position angle 65°".
Physical Information:

NGC 3969
Discovered (1886) by
Ormond Stone
Also observed (date?) by Herbert Howe
A magnitude 12.9 lenticular galaxy (type SB0/a?) in Crater (RA 11 55 09.1, Dec -18 55 38)
Historical Identification: Per Dreyer, NGC 3969 (Ormond Stone list II (#453), 1860 RA 11 48 17, NPD 107 58.0) is "extremely faint, very small, gradually brighter middle and nucleus, 10th magnitude star 4 arcmin to northwest". The second IC adds (per Howe) "RA 11 48 01, NPD 108 08.9, the star is 8.5 magnitude, and is nearly north".
Physical Information:

NGC 3970
Discovered (Mar 9, 1828) by
John Herschel
A magnitude 13.4 lenticular galaxy (type S0?) in Crater (RA 11 55 28.1, Dec -12 03 41)
Historical Identification: Per Dreyer, NGC 3970 (= GC 2623 = JH 1020, 1860 RA 11 48 19, NPD 101 15.9) is "faint, small, round, pretty suddenly brighter middle, western of 2", the other being NGC 3974.
Physical Information:

NGC 3971 (=
NGC 3984)
Discovered (Feb 3, 1788) by William Herschel (and later listed as NGC 3971)
Also observed (Apr 2, 1827) by John Herschel (and later listed as NGC 3971)
Discovered (Apr 10, 1831) by John Herschel (and later listed as NGC 3984)
A magnitude 12.7 lenticular galaxy (type S0?) in Ursa Major (RA 11 55 36.3, Dec +29 59 45)
Historical Identification: Per Dreyer, NGC 3971 (= GC 2624 = JH 1019 = WH II 724, 1860 RA 11 48 20, NPD 59 13.7) is "pretty faint, very small, round, brighter middle".
Physical Information:

NGC 3972
Discovered (Apr 14, 1789) by
William Herschel
Also observed (date?) by Heinrich d'Arrest
A magnitude 12.3 spiral galaxy (type SBbc?) in Ursa Major (RA 11 55 45.3, Dec +55 19 12)
Historical Identification: Per Dreyer, NGC 3972 (= GC 2618 = WH II 789, d'Arrest, 1860 RA 11 48 24, NPD 33 54.7) is "pretty bright, extended".
Physical Information:

NGC 3973
Discovered (Mar 15, 1855) by
R. J. Mitchell
A magnitude 15.0 spiral galaxy (type S?) in Leo (RA 11 55 37.0, Dec +11 59 50)
Historical Identification: Per Dreyer, NGC 3973 (= GC 2622, 3rd Lord Rosse, 1860 RA 11 48 24, NPD 77 13) is "extremely faint, extremely small, 10th magnitude star 1 arcmin to southeast (requires verification)".
Discovery Notes: (standard paragraph about 3rd Lord Rosse's assistants)
Physical Information:

NGC 3974
Discovered (Mar 9, 1828) by
John Herschel
A magnitude 13.4 lenticular galaxy (type SB0/a?) in Crater (RA 11 55 40.1, Dec -12 01 38)
Historical Identification: Per Dreyer, NGC 3974 (= GC 2625 = JH 1021, 1860 RA 11 48 32, NPD 101 12.7) is "very faint, small, round, brighter middle, eastern of 2", the other being NGC 3970.
Physical Information:

NGC 3975
Discovered (Feb 21, 1874) by
Lawrence Parsons, 4th Lord Rosse
A magnitude 15.3 spiral galaxy (type Sb?) in Ursa Major (RA 11 55 53.7, Dec +60 31 47)
Historical Identification: Per Dreyer, NGC 3975 (= GC 5593, 4th Lord Rosse, 1860 RA 11 48 33, NPD 28 41.5) is "very faint, very small, II 840 seventeen seconds of time to the east", "(WH) II 840" being NGC 3978.
Physical Information:

NGC 3976
Discovered (Apr 13, 1784) by
William Herschel
Also observed (Dec 27, 1827) by John Herschel
Also observed (Mar 26, 1886) by Johann Palisa
A magnitude 11.5 spiral galaxy (type SBb?) in Virgo (RA 11 55 57.2, Dec +06 44 54)
Historical Identification: Per Dreyer, NGC 3976 (= GC 2626 = JH 1022 = WH II 132, 1860 RA 11 48 47, NPD 82 28.3) is "bright, pretty large, considerably extended 30°, very suddenly much brighter middle and nucleus".
Discovery Notes: Palisa's observation is on page 349 of Steinicke's S360, and not only gives the (1886) position but also states that the object is GC 2626.
Physical Information:

NGC 3977 (=
NGC 3980)
Discovered (Apr 14, 1789) by William Herschel (and later listed as NGC 3977)
Also observed (date?) by John Dreyer (and later listed as NGC 3977)
Discovered (Apr 16, 1885) by Lewis Swift (and later listed as NGC 3980)
A magnitude 13.4 spiral galaxy (type Sab?) in Ursa Major (RA 11 56 07.3, Dec +55 23 27)
Historical Identification: Per Dreyer, NGC 3977 (= GC 2619 = WH II 790, Dreyer, 1860 RA 11 48 48, NPD 33 50.4) is "faint, small".
Discovery Notes: Check 4th Lord Rosse's paper for Dreyer's observation
Physical Information:

NGC 3978
Discovered (Mar 19, 1790) by
William Herschel
Also observed (Apr 14, 1831) by John Herschel
A magnitude 12.7 spiral galaxy (type SBbc?) in Ursa Major (RA 11 56 10.6, Dec +60 31 22)
Historical Identification: Per Dreyer, NGC 3978 (= GC 2627 = JH 1023 = WH II 840, 1860 RA 11 48 50, NPD 28 42.0) is "considerably faint, small, a little extended, brighter middle, 8th magnitude star 6 arcmin distant at position angle 90°".
Physical Information:

NGC 3979 (=
IC 2976)
Discovered (Apr 23, 1881) by Edward Holden (and later listed as NGC 3979)
Also observed (Apr 27, 1886) by Lewis Swift (and later listed as NGC 3979)
Discovered (May 23, 1897) by Lewis Swift (and later listed as IC 2976)
A magnitude 12.9 lenticular galaxy (type S0?) in Virgo (RA 11 56 01.1, Dec -02 43 14)
Historical Identification: Per Dreyer, NGC 3979 (Holden (#6), Swift list III (#??), 1860 RA 11 48 55, NPD 91 55.0) is "pretty faint, 11th or 12th magnitude star to northeast".
Physical Information:

NGC 3980 (=
NGC 3977)
Discovered (Apr 14, 1789) by William Herschel (and later listed as NGC 3977)
Discovered (Apr 16, 1885) by Lewis Swift (and later listed as NGC 3980)
A magnitude 13.4 spiral galaxy (type Sab?) in Ursa Major (RA 11 56 07.3, Dec +55 23 27)
Historical Identification: Per Dreyer, NGC 3980 (Swift list I (#18), 1860 RA 11 48 56, NPD 33 50.0) is "extremely faint, pretty large, extended, double star near".
Physical Information:

NGC 3981 (= PGC 37496)
Discovered (Feb 7, 1785) by
William Herschel
A magnitude 11.0 spiral galaxy (type SAB(rs)bc? pec) in Crater (RA 11 56 07.0, Dec -19 53 50)
Historical Identification: Per Dreyer, NGC 3981 (= GC 2628 = WH III 274, 1860 RA 11 49 04, NPD 109 07.0) is "very faint, pretty large, irregular figure". The position precesses to RA 11 56 12.2, Dec -19 53 45, less than 1.2 arcmin east 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 1725 km/sec (and H0 = 70 km/sec/Mpc), NGC 3981 is about 80 million light years away, in good agreement with redshift-independent distance estimates of 50 to 95 million light years (the ESO image discussion lists a distance of 65 million light years). Given that and its apparent size of 2.9 by 0.6 arcmin (from the images below), the bright central part of the galaxy is about 65 to 70 thousand light years across, while its extended arms, which have an apparent size of roughly 7 by 5.5 arcmin, span about 160 to 165 thousand light years. The extensions suggest some kind of interaction with another galaxy, long enough ago that there is now nothing close enough to be an obvious candidate for such an interaction. However, NGC 3981 is part of the NGC 4038 group, named after one of the pair of galaxies called The Antennae, so some member of the group is almost certainly the cause of the unusual structure seen here.
DSS image of region near spiral galaxy NGC 3981
Above, a 12 arcmin wide DSS image centered on NGC 3981
Below, a 4 by 4.4 arcmin wide image of the galaxy (Image Credit Carnegie-Irvine Galaxy Survey; used by permission)
Carnegie-Irvine Galaxy Survey image of spiral galaxy NGC 3981
Below, a 6 by 7.2 arcmin wide image of the galaxy (Image Credit ESO)
ESO image of spiral galaxy NGC 3981
Below, a 3.5 by 5 arcmin wide image of the galaxy (Image credit as above)
ESO image of central part of spiral galaxy NGC 3981

NGC 3982
Discovered (Apr 14, 1789) by
William Herschel
Also observed (Feb 10, 1831) by John Herschel
Also observed (date?) by Heinrich d'Arrest
Also observed (date?) by Herman Schultz
A magnitude 11.0 spiral galaxy (type SBb?) in Ursa Major (RA 11 56 28.0, Dec +55 07 30)
Historical Identification: Per Dreyer, NGC 3982 (= GC 2620 = JH 1017 = WH IV 62, d'Arrest, Schultz, 1860 RA 11 49 09, NPD 34 05.8) is "bright, pretty large, round, gradually then suddenly brighter middle and disc".
Physical Information:

NGC 3983
Discovered (Apr 10, 1785) by
William Herschel
Also observed (Mar 28, 1832) by John Herschel
A magnitude 14.0 lenticular galaxy (type S0/a?) in Leo (RA 11 56 23.6, Dec +23 52 05)
Historical Identification: Per Dreyer, NGC 3983 (= GC 2629 = JH 1024 = WH III 343, 1860 RA 11 49 10, NPD 65 20.9) is "considerably faint, considerably small, round, pretty suddenly brighter middle".
Physical Information:

NGC 3984 (=
NGC 3971)
Discovered (Feb 3, 1788) by William Herschel (and later listed as NGC 3971)
Discovered (Apr 10, 1831) by John Herschel (and later listed as NGC 3984)
Looked for but not observed (date?) by Max Wolf (while listed as NGC 3984)
A magnitude 12.7 lenticular galaxy (type S0?) in Ursa Major (RA 11 55 36.3, Dec +29 59 45)
Historical Identification: Per Dreyer, NGC 3984 (= GC 2630 = JH 1026, 1860 RA 11 49 23, NPD 60 13.4) is "extremely faint, small, round, brighter middle". The second IC says "3984: Nothing in this place, Wolf list VIII (h. one observation, about which he seemed rather doubtful)".
Physical Information:

NGC 3985
Discovered (Feb 5, 1788) by
William Herschel
Also observed (Mar 7, 1831) by John Herschel
A magnitude 12.5 spiral galaxy (type SBm?) in Ursa Major (RA 11 56 41.5, Dec +48 20 08)
Historical Identification: Per Dreyer, NGC 3985 (= GC 2631 = JH 1025 = WH III 707, 1860 RA 11 49 24, NPD 40 53.0) is "very faint, considerably small, another suspected".
Physical Information:

NGC 3986 (=
NGC 3966)
Discovered (Apr 29, 1827) by John Herschel (and later listed as NGC 3986)
Discovered (May 8, 1864) by Heinrich d'Arrest (and later listed as NGC 3966)
A magnitude 12.7 lenticular galaxy (type S0/a?) in Ursa Major (RA 11 56 44.2, Dec +32 01 17)
Historical Identification: Per Dreyer, NGC 3986 (= GC 2632 = JH 1027, 1860 RA 11 49 30, NPD 57 12.0) is "pretty faint, small, pretty much extended 90°±, 11th magnitude star near".
Physical Information:

NGC 3987
Discovered (Apr 6, 1785) by
William Herschel
Also observed (Apr 25, 1854) by R. J. Mitchell
A magnitude 12.9 spiral galaxy (type Sb?) in Leo (RA 11 57 20.9, Dec +25 11 43)
Historical Identification: Per Dreyer, NGC 3987 (= GC 2638, 3rd Lord Rosse, 1860 RA 11 50 07, NPD 64 01.5) is "faint, much extended".
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:

NGC 3988
Discovered (Apr 13, 1831) by
John Herschel
A magnitude 13.3 elliptical galaxy (type E1?) in Leo (RA 11 57 24.2, Dec +27 52 41)
Historical Identification: Per Dreyer, NGC 3988 (= GC 2633 = JH 1028, 1860 RA 11 50 10, NPD 61 20.7) is "very faint, small, round, brighter middle like a star, western of 2", the other almost certainly being NGC 4004, but not specified as such in the NGC.
Physical Information:

NGC 3989
Discovered (Apr 27, 1854) by
R. J. Mitchell
A magnitude 14.9 spiral galaxy (type Sb?) in Leo (RA 11 57 26.6, Dec +25 13 58)
Historical Identification: Per Dreyer, NGC 3989 (= GC 2639, 3rd Lord Rosse, 1860 RA 11 50 12, NPD 63 58±) is "extremely faint, very small, round".
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:

NGC 3990
Discovered (Apr 14, 1789) by
William Herschel
Also observed (May 2, 1831) by John Herschel
A magnitude 12.6 lenticular galaxy (type E/S0?) in Ursa Major (RA 11 57 35.5, Dec +55 27 31)
Historical Identification: Per Dreyer, NGC 3990 (= GC 2634 = JH 1029 = WH II 791, 1860 RA 11 50 17, NPD 33 45.7) is "pretty faint, small, a little extended, pretty suddenly a little brighter middle".
Physical Information:

NGC 3991
Discovered (Feb 5, 1864) by
Heinrich d'Arrest
A magnitude 13.1 (type Im? pec) in Ursa Major (RA 11 57 30.7, Dec +32 20 08)
Historical Identification: Per Dreyer, NGC 3991 (= GC 5594, d'Arrest, 1860 RA 11 50 18, NPD 56 52.4) is "faint, small, a little extended, 1st of 3", the others being NGC 3394 and 3395.
Physical Information:

NGC 3992 (=
M109 = PGC 37617)
Supposedly but undoubtedly not discovered (Mar 12, 1781) by Pierre Méchain
Discovered (between late March and early May 1781) by Charles Messier but not added to his Catalog
Independently discovered (Apr 12, 1789) by William Herschel
Also observed (Feb 17, 1831) by John Herschel
Appended (1953) to Messier's Catalog by Owen Gingerich as M109
A magnitude 9.8 spiral galaxy (type SB(rs)bc?) in Ursa Major (RA 11 57 35.4, Dec +53 22 25)
Historical Identification: Per Dreyer, NGC 3992 (= GC 2635 = JH 1030 = WH IV 61, 1860 RA 11 50 19, NPD 35 51.3) is "considerably bright, very large, pretty much extended, suddenly brighter middle and bright mottled but not resolved nucleus". The position precesses to RA 11 57 36.0, Dec +53 21 57, barely south of the nucleus of the galaxy and well within its outline, there is nothing else nearby and the description fits, so the identification is certain.
Discovery Notes: Méchain's observation of Mar 12, 1781 was long thought to be the first observation of this object, but as of his letter of May 6, 1783 to Bernoulli he had still not determined its position, and in 2006 Henrik Bril found that based on the "Fortin Chart" Méchain used, he almost certainly observed NGC 3953, instead. Sometime soon after (in late March, April or early May of 1781) Messier observed both NGC 3953 and 3992, and recorded a handwritten position in his personal copy of his Catalog that has the right ascension of NGC 3953, but the declination of NGC 3992. That position is obviously not terribly good, but since its declination agrees with that of NGC 3992, it is reasonably certain that Messier did observe that galaxy, and on that basis Owen Gingerich added it to the Messier Catalog as M109 (at the time thinking that Méchain was the original discoverer, but since it was recorded by Messier, Gingerich would undoubtedly have added it to the Messier Catalog regardless of which of the French astronomers had first right of discovery). Since Messier did not add it to his published Catalog, neither the Herschels nor Dreyer were aware of its prior observation when compiling their various catalogs, causing the lack of any mention of Méchain or Messier in the NGC.
Physical Information: Based on a recessional velocity of 1050 km/sec, NGC 3992 is about 50 million light years away, in reasonable agreement with widely varying redshift-independent distance estimates of 35 to 115 million light years. Given that and its apparent size of 7.3 by 4.2 arcmin, it is about 100 thousand light years across.
SDSS image of region near spiral galaxy NGC 3992, also known as M109
Above, a 12 arcmin wide SDSS image centered on NGC 3992
Below, another image of of the galaxy (Image Credit AURA, NSF, NOAO)
NOAO image of spiral galaxy NGC 3992, also known as M109

NGC 3993
Discovered (Apr 6, 1785) by
William Herschel
Also observed (Apr 25, 1854) by R. J. Mitchell
A magnitude 13.7 spiral galaxy (type Sb?) in Leo (RA 11 57 37.6, Dec +25 14 25)
Historical Identification: Per Dreyer, NGC 3993 (= GC 2640, 3rd Lord Rosse, 1860 RA 11 50 25, NPD 63 58.8) is "very faint, pretty small, extended, 3 stars near".
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:

NGC 3994
Discovered (Apr 6, 1864) by
Heinrich d'Arrest
A magnitude 12.7 spiral galaxy (type Sc? pec) in Ursa Major (RA 11 57 36.8, Dec +32 16 39)
Historical Identification: Per Dreyer, NGC 3994 (= GC 5595, d'Arrest, 1860 RA 11 50 25, NPD 56 56.1) is "pretty bright, very small, 2nd of 3", the others being NGC 3391 and 3395.
Physical Information:

NGC 3995
Discovered (Feb 5, 1864) by
Heinrich d'Arrest
A magnitude 12.4 spiral galaxy (type SBm?) in Ursa Major (RA 11 57 44.0, Dec +32 17 35)
Historical Identification: Per Dreyer, NGC 3995 (= GC 5596, d'Arrest, 1860 RA 11 50 32, NPD 56 55.0) is "faint, pretty large, irregularly round, brighter middle, 3rd of 3", the others being NGC 3391 and 3394.
Physical Information:

NGC 3996
Discovered (Apr 23, 1832) by
John Herschel
A magnitude 13.5 spiral galaxy (type Sc?) in Leo (RA 11 57 46.1, Dec +14 17 51)
Historical Identification: Per Dreyer, NGC 3996 (= GC 2636 = JH 1032, 1860 RA 11 50 34, NPD 74 55.5) is "very faint, pretty large, round, 2 stars to east".
Physical Information:

NGC 3997
Discovered (Feb 19, 1827) by
John Herschel
A magnitude 13.5 spiral galaxy (type SBb? pec) in Leo (RA 11 57 48.5, Dec +25 16 15)
Historical Identification: Per Dreyer, NGC 3997 (= GC 2641 = JH 1033, 1860 RA 11 50 36, NPD 63 57.0) is "pretty faint, very small, extended 25°, between 2 stars".
Physical Information:

NGC 3998 (= PGC 37642)
Discovered (Apr 14, 1789) by
William Herschel
Also observed (May 2, 1831) by John Herschel
A magnitude 10.7 lenticular galaxy (type SA(r)0) in Ursa Major (RA 11 57 55.9, Dec +55 27 14)
Historical Identification: Per Dreyer, NGC 3998 (= GC 2637 = JH 1031 = WH I 229, 1860 RA 11 50 38, NPD 33 46.0) is "considerably bright, pretty small, round, very gradually then suddenly much brighter middle".
Physical Information: Apparent size 2.7 by 2.3 arcmin. Used by the de Vaucouleurs Atlas of Galaxy Types as an example of galaxy type SA(r)0°.
SDSS image of lenticular galaxy NGC 3998
Above, a 3 arcmin wide closeup of NGC 3998
Below, a 12 arcmin wide region centered on the galaxy, also showing NGC 3990
SDSS image of region near lenticular galaxy NGC 3998, also showing NGC 3990

NGC 3999 (= PGC 37647)
Discovered (Apr 25, 1878) by
Lawrence Parsons, 4th Lord Rosse
A magnitude 14.7 lenticular galaxy (type S0?) in Leo (RA 11 57 56.4, Dec +25 04 06)
Historical Identification: Per Dreyer, NGC 3999 (4th Lord Rosse, 1860 RA 11 50 44, NPD 64 09.4) is "very faint, small".
Physical Information: Apparent size 0.5 by 0.3 arcmin.
SDSS image of region near lenticular galaxy NGC 3999, also showing NGC 4000 and 4005 (glare from 8th-magnitude HD 103913 to be reduced later)
Above, a 12 arcmin wide region centered on NGC 3999, also showing NGC 4000 and 4005
Below, a 2.4 arcmin wide SDSS image of the galaxy
SDSS image of lenticular galaxy NGC 3999
Celestial Atlas
(NGC 3900 - 3949) ←NGC Objects: NGC 3950 - 3999→ (NGC 4000 - 4049)