Historical (Mis)Identification: Per Dreyer, NGC 3500 (= GC 2284 = WH III 967 = GC 2285 = WH III 968, 1860 RA 10 55 10, NPD 13 27.2) is "a {III 967 = very faint, III 968 = extremely faint} double nebula, very near (Place very questionable)". The position precesses to RA 11 05 35.7, Dec +75 47 36 (whence the position above), but there is nothing there nor near there. As it turns out (per Steinicke), William Herschel misaligned his telescope relative to the meridian by about 7 degrees on the night in question, leading to large inconsistent errors in the position of every object observed that night. The same error was made in his observations of Apr 5, 1801, which Herschel happened to realize a few days later, stating that the telescope was misaligned with the meridian on that date by at least 5 or 6 degrees; but he failed to notice that he must have made the same error in his observations of April 2, so the positions in the GC and NGC for the fifteen objects observed on that date were never corrected. Fortunately, Dreyer recognized that there was something wrong with the positions of those objects and asked the Astronomer Royal to take photographs of the regions in question, leading to a list of corrections in Dreyer's 1911 MNRAS paper about necessary changes to Herschel's positions, and his 1912 paper about the same topic. However, what Dreyer and the staff of the Royal Observatory did was look at the regions most likely to be where Herschel observed and pick the galaxies which happened to be closest to his poor positions. A similar effort mounted in the 1970's by the RNGC (Revised NGC) led to the misidentification of many NGC objects (in fact, that catalog contains far more errors than the original NGC), and although it is quite possible (if not probable) that NGC 3465 is Herschel's III 967 and supposedly possible that PGC 33277 is his III 968, it is absolutely certain that both identifications cannot be correct, as Herschel stated that the double nebula was a very close pair, and those two galaxies are not at all close to each other, being separated by 2 minutes 20 seconds in right ascension, meaning that Herschel could not possibly have called them a "double nebula". However, based on Dreyer's and the RNGC's almost certainly incorrect assignments, many references have accepted PGC 33277 as the correct identification of NGC 3500, so this entry is essentially a warning that that identification must be absolutely incorrect.
Additional Note: Corwin, pointing out the problem with Herschel's description, feels that the identification of PGC 33277 as part of NGC 3500 must be wrong or if right, that III 967 is not NGC 3465, but instead some other object, such as the faint double star just southwest of PGC 33277. However, Steve Gottlieb, while doing his excellent visual survey of the NGC objects, could not see the pair of stars to the southwest of PGC 33277, so the faint double cannot be III 967, and PGC 33277 cannot be part of NGC 3500. Gottlieb also notes that there is a star which might be Herschel's III 968, providing that Herschel made certain mistakes in his description of the region near NGC 3465, so it is discussed in the second entry below.
Conclusion: Given the problems noted above, although I have noted the frequent error of misidentifying PGC 33277 as part of NGC 3500 in the entry immediately below, I feel certain that this galaxy is not part of NGC 3500, and that NGC 3500 should be listed (as shown in the title for this entry) as lost or nonexistent. (My current suspicion is that NGC 3465 has been correctly identified as Herschel's III 967, but that is another matter entirely.)

Historical Misidentification: See the entry for NGC 3500. Note that the 15th magnitude double star to the west southwest of PGC 33277 could not be seen by Steve Gottlieb in observations of the region (so it cannot be Herschel's III 967, which was brighter than his III 968), which means that PGC 33277 cannot be part of NGC 3500, since that was listed by Dreyer as a close double nebula, not as a single object of any sort.
Physical Information: Based on a recessional velocity of 3465 km/sec (and H₀ = 70 km/sec/Mpc), PGC 33277 is about 160 million light years away, but some references list the recessional velocity as 7400 km/sec, most likely because the problem with the identification has led to measurements of different galaxies being assigned to the same object. If the larger recessional velocity is the correct one, then a straightforward calculation would put the galaxy about 345 million light years away. However, for galaxies at that distance, we should take into account the expansion of the Universe during the time it took their light to reach us. Doing that shows that the galaxy would then have been about 335 million light years away at the time the light by which we see it was emitted, about 340 million years ago (the difference between the two numbers being due to the expansion of the intervening space during the light-travel time). If the smaller distance is correct, then the galaxy's apparent size of about 1.15 by 0.5 arcmin (from the images below) would correspond to about 50 to 55 thousand light years. However, if the larger distance is correct, that apparent size would correspond to about 110 to 115 thousand light years. Also, in that case the galaxy would be a member of the NGC 3523 group of galaxies, all of which have recessional velocities in the 7000+ km/sec range. Only future measurements of PGC 33277's redshift can determine which of the two possibilities is correct.

Historical (Mis?)Identification: See NGC 3500 for a detailed discussion of the very problematic identification of that almost certainly lost or nonexistent NGC object. This entry is based on Steve Gottlieb's careful visual observations of the regions near the two galaxies usually identified as NGC 3465 and NGC 3500. In his detailed discussion of NGC 3500 he notes that there is a star about 40 arcseconds southeast of NGC 3465 which might be Herschel's III 968, provided that Herschel misidentified the star as nebulous and that he mistakenly stated that it was northeast of III 967, instead of southeast (a fair copy of Herschel's observation by his sister Caroline reads "Two, the 1st vF, vS. The 2nd eF and smaller than the first. It is a little more north and following, but very near to it."). Having such a double error in the fair copy seems unlikely but not necessarily impossible, so presuming that the identification of NGC 3645 is correct, the star listed here might be (though probably is not) the rest of the otherwise lost or nonexistent NGC 3500, which (based on Caroline Herschel's transcription) was a close double nebula.

Historical Identification: Per Dreyer, NGC 3501 (Stephan list XI (#10), 1860 RA 10 55 22, NPD 71 15.3) is "very faint, much extended north-south, gradually brighter middle, 3 arcmin long". The position precesses to RA 11 02 48.6, Dec +17 59 34, right on the galaxy listed above, the description fits and there is nothing comparable nearby, so the identification is certain.
Physical Information: NGC 3501 is an edge-on spiral galaxy, paired with NGC 3507. Based on a recessional velocity of 1130 km/sec (and H₀ = 70 km/sec/Mpc), the galaxy is about 50 to 55 million light years away, in fair agreement with redshift-independent distance estimates of 65 to 85 million light years. Given that and its apparent size of 4.0 by 0.5 arcmin (from the images below), it is about 60 to 65 thousand light years across.

Historical Identification: Per Dreyer, NGC 3502 (Leavenworth list I (#181), 1860 RA 10 55 30, NPD 104 12.3) is "extremely faint, pretty large, irregularly round, gradually a little brighter middle". The position precesses to RA 11 02 27.5, Dec -14 57 25, but there is nothing there. Per Corwin, the description of list I #180 (by Leavenworth) and list I #181 (by Stone) are essentially identical save for the fact that Stone's right ascension is 4 minutes to the east of Leavenworth's. Such an error in right ascensions (namely, too large) is very common in the Leander-McCormick lists of nebulae, so the fact that NGC 3502 is a duplicate entry for NGC 3479 is essentially certain. Corwin also notes that in the RNGC another galaxy, about 50 arcmin north of Leavenworth's position and a few tenths of a minute of time to the west, is identified as NGC 3502, and states that since LM errors are almost always in right ascension and almost never in declination, the RNGC identification is almost certainly wrong; but since a few references (e.g., Wikisky) still use the RNGC (mis)identification, the following entry serves as a warning about that error.
Physical Information: Given the duplicate entry, see NGC 3479 for anything else.

Historical Misidentification: See NGC 3502 for a discussion of its correct identification, and a note about this incorrect RNGC identification. This galaxy is about 50 arcmin to the north and a few tenths of a minute of time to the west of Leavenworth's observation of NGC 3479, which is certainly the most likely identification of NGC 3502.
Physical Information: Based on a recessional velocity of 4605 km/sec (and H₀ = 70 km/sec/Mpc), PGC 33306 is about 215 million light years away. Given that and its apparent size of about 1.05 by 0.9 arcmin (from the images below), it is about 65 thousand light years across.

Historical Identification: Per Dreyer, NGC 3503 (= GC 2286 = JH 3311, 1860 RA 10 55 33, NPD 149 05.8) is "3 small (faint) stars of 10th magnitude in very faint nebula". The position precesses to RA 11 01 19.0, Dec -59 50 54, almost dead center on the nebula, the description fits and there is no comparable object nearby, so the identification is certain.
Note About PGC Designation: For purposes of completeness, LEDA assigns a PGC designation to this object, even though it isn't a galaxy. However, a search of the database for the PGC designation returns no result, so the designation is shown in quotes.
Physical Information: The nebula is thought to be about 9450 light years away, with an uncertainty of about 1300 light years. Given that and its apparent size of about 3.35 by 2.95 arcmin for its fainter outer regions and about 2.15 by 2.0 arcmin for its brighter central region (both sizes from the images below), the outer region covers about 9 light years, and the inner region about 6 light years.

Historical Identification: Per Dreyer, NGC 3504 (= GC 2287 = JH 810 = WH I 88, 1860 RA 10 55 35, NPD 61 16.5) is "bright, large, extended, much brighter middle and nucleus, partially resolved (some stars seen), preceding (western) of 2", the other being NGC 3512. The position precesses to RA 11 03 11.7, Dec +27 58 21, almost dead center on 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 1525 km/sec (and H₀ = 70 km/sec/Mpc), NGC 3504 is about 70 million light years away, in reasonable agreement with widely varying redshift-independent distance estimates of about 30 to 85 million light years. Given that and its apparent size of about 2.7 by 2.3 arcmin (from the images below), the galaxy is about 55 thousand light years across. The galaxy is classified as a starburst galaxy due to the exceptional brightness of its central regions.

Historical Identification: Per Dreyer, NGC 3505 (= GC 2288 = JH 3312, 1860 RA 10 55 50, NPD 104 44.4) is "pretty faint, small, round, gradually a little brighter middle, 14th magnitude star near".
Physical Information:

Historical Identification: Per Dreyer, NGC 3506 (= GC 2289 = JH 811 = WH III 22, 1860 RA 10 55 54, NPD 78 10.4) is "very faint, considerably small, round, very gradually very little brighter middle".
Physical Information:

Historical Identification: Per Dreyer, NGC 3507 (= GC 2290 = JH 812 = WH IV 7, 1860 RA 10 55 58, NPD 71 06.7) is "considerably faint, pretty large, round, suddenly brighter middle small star, 9th magnitude star attached 25°".
Physical Information: A face-on barred spiral, paired with NGC 3501. Based on recessional velocity of 980 km/sec, about 45 million light years away, in fair agreement with a redshift-independent distance estimate of 65 million light years. Given that and apparent size of 3.4 by 2.9 arcmins, about 45 thousand light years in diameter.

Historical Identification: Per Dreyer, NGC 3508 (= GC 2291 = JH 814 = WH II 507, 1860 RA 10 56 04, NPD 105 32.1) is "faint, {per WH small, per JH very large}, brighter middle, star to northeast involved". The second IC notes (per Howe) "is small, and the star half an arcmin northeast is not involved". (Howe's paper actually says "Of this the NGC remarks, star northeast involved. I see only a star of magnitude 12, 30 or 40 arcsec distant at 20°. (WH) noted the nebula as "(small)", with which my estimate of its size agrees; (JH) called it "very large", and probably thought that the star just mentioned lay within the outlying nebulosity." The position precesses to RA 11 03 00.4, Dec -16 17 15, well within the eastern outline of the galaxy listed above, the description perfectly fits Howe's comments and there is nothing else nearby, so the identification is certain.
Physical Information:

Historical Identification: Per Dreyer, NGC 3509 (= GC 2292 = WH III 598, 1860 RA 10 56 05, NPD 84 28.3) is "extremely faint, small, a little extended?"
Physical Information:

Historical Identification: Per Dreyer, NGC 3510 (= GC 2293 = JH 813 = WH II 365, 1860 RA 10 56 06, NPD 60 21.7) is "faint, large, considerably extended, 7th magnitude star 8 arcmin distant at position angle 310°".
Physical Information:

Historical Identification: Per Dreyer, NGC 3511 (= GC 2294 = WH V 39, 1860 RA 10 56 27, NPD 112 21.3) is "very faint, very large, much extended".
The second IC adds "NGC 3511 = V.39. Not found by Innes, while 3513 = V.40 (same description) was well seen (M.N., lix. p. 339)".
Physical Information:

Historical Identification: Per Dreyer, NGC 3512 (= GC 2295 = JH 815 = WH II 366, 1860 RA 10 56 27, NPD 61 12.7) is "faint, pretty small, round, pretty gradually brighter middle, following (eastern) of 2", the other being NGC 3504.
Physical Information:

Historical Identification: Per Dreyer, NGC 3513 (= GC 2296 = WH V 40, 1860 RA 10 56 44, NPD 112 29.3) is "very faint, very large, much extended".
The second IC adds "NGC 3511 = V.39. Not found by Innes, while 3513 = V.40 (same description) was well seen (M.N., lix. p. 339)".
Physical Information:

Historical Identification: Per Dreyer, NGC 3514 (= GC 2297 = JH 3313, 1860 RA 10 56 50, NPD 108 01.7) is "very faint, pretty large, round, very gradually very little brighter middle".
Physical Information:

Historical Identification: Per Dreyer, NGC 3515 (Stephan list XII (#41), 1860 RA 10 57 01, NPD 61 01.2) is "very faint, small, round, several extremely faint stars involved".
Physical Information:

Historical Identification: Per Dreyer, NGC 3516 (= GC 2298 = JH 816 = WH II 336, 1860 RA 10 57 02, NPD 16 41.4) is "pretty bright, very small, irregularly round, pretty suddenly much brighter starlike middle".
Physical Information:

Historical Identification: Per Dreyer, NGC 3517 (= GC 2299 = JH 817 = WH II 884, 1860 RA 10 57 13, NPD 32 43.5) is "extremely faint, small, round, very gradually brighter middle".
Identification Note: Some references list PGC 33526, the faint galaxy just north of NGC 3517, as part of the NGC object; but given the description in the NGC, the fainter galaxy must have been far too faint for either Herschel to notice. So its entry (below) only lists it as a possible companion.
Physical Information: Vr 8210 km/sec, z 0.027385

Historical Identification: This galaxy is sometimes listed as part of NGC 3517, but it is far too faint to be part of the NGC object. However, its recessional velocity is nearly identical to that of the brighter galaxy so they may indeed be a physical pair.
Physical Information: Vr 8300 km/sec, z 0.027685

Historical Identification: Per Dreyer, NGC 3518 (Leavenworth list I (#182), 1860 RA 10 57 30, NPD 95 48.3) is "extremely faint, extremely small, a little extended (110°)".
Discovery Notes: Although Dreyer refers to Leavenworth's list I, the paper was actually published by Stone, and although most of the observations in Stone's paper were done by Leavenworth, some were done by other observers, and in this case Stone was the actual observer.
Physical Information: Given the duplicate entry, see NGC 3110 for anything else.

Physical Information: Since NGC 3518 is an erroneous and duplicate observation of NGC 3110, see the corresponding entry for its probable companion following NGC 3110's entry.

Historical Identification: Per Dreyer, NGC 3519 (= GC 2300 = JH 3314, 1860 RA 10 58 19, NPD 150 36.6) is a "cluster, pretty rich, pretty compressed".
Physical Information:

Historical Identification: Per Dreyer, NGC 3520 (Leavenworth list II (#431), 1860 RA 10 58 37, NPD 107 11.4) is "extremely faint, very small, irregularly round, gradually brighter middle, several very faint stars involved" (Leavenworth's actual description was "magnitude 15.3, diameter 0.4 arcmin, irregularly round, gradually a pretty much brighter middle, several faint stars involved".). The position precesses to RA 11 05 32.5, Dec -17 56 41, but there is nothing there nor near there. Various suggestions have been made as to what Leavenworth observed, but they are sufficiently uncertain that I have decided to list NGC 3520 as lost or nonexistent, and to treat the suggested possibilities as separate entries.
Physical Information:

Listed as NGC 3520 in LEDA and NED. Steinicke states that it is a quadruple system, but only lists PGC 33648 as the NGC object. Of the four objects, two would be merely Leavenworth's "several faint stars involved". Even the "peculiar" extension to the southeast of PGC 873840 may be merely another faint star, as no currently available image is very good.

A group of 4 or 5 stars, 0.8 by 0.6 arcmin in size, just northwest of Leavenworth's position.

Historical (Mis?)Identification: Only include reasoning behind the possible identification as NGC 3520.
Physical Information Whether equal to NGC 3520 or not, see NGC 3514 for anything else.

Listed as NGC 3520 in SIMBAD

Historical Identification: Per Dreyer, NGC 3521 (= GC 2301 = JH 818 = WH I 13, 1860 RA 10 58 38, NPD 89 16.9) is "considerably bright, considerably large, much extended 140°±, very suddenly much brighter middle and nucleus".
Physical Information:

Historical Identification: Per Dreyer, NGC 3522 (Swift list III (#59), 1860 RA 10 58 55, NPD 69 09.7) is "pretty faint, very small, a little extended".
Physical Information:

Historical Identification: Per Dreyer, NGC 3523 (= GC 2302 = WH II 904, 1860 RA 10 59 05, NPD 13 33.3) is "faint, pretty large, a little brighter middle (place doubtful)".
Discovery Notes: One of a multitude of objects observed by Herschel with his telescope misaligned with the meridian, leading to large errors in the position. A short discussion here and a lengthy one elsewhere (link?) explain the situation in detail.
Physical Information: The brightest of three galaxies in the NGC 3523 group (consisting of NGC 3523, 3500, and 3465). Based on recessional velocity of 7165 km/sec, about 320 million light years away. Given that and apparent size of 1.5 by 1.5 arcmin, about 140 thousand light years in diameter.

Historical Identification: Per Dreyer, NGC 3524 (= GC 2303 = JH 819 = WH III 23, 1860 RA 10 59 14, NPD 77 51.4) is "faint, small, a little extended, pretty suddenly brighter middle, 2 stars to northwest in line".
Physical Information:

Historical Identification: Per Dreyer, NGC 3525 (Ormond Stone list I (#183), 1860 RA 10 59 30, NPD 108 42.3) is "faint, pretty small, gradually brighter middle and nucleus".
Physical Information: Given the duplicate entries, see NGC 3497 for anything else.

Historical Identification: Per Dreyer, NGC 3526 (= GC 5546, Marth 215, 1860 RA 10 59 40, NPD 82 05) is "extremely faint, very much extended, position angle 50°±". The first IC notes "3531 to be struck out, is = 3526 (per Spitaler)"; so the identity of the two listings has been known for more than a century.
Discovery Notes: In a discussion of his Nova 16 (observed Mar 7, 1891), which became IC 670, Spitaler states that it is not NGC 3531, and that Holden actually observed NGC 3526, but used the wrong reference star (namely, he mistook BD+7°.2412 for BD+7°.2413), thereby obtaining a position too far to the east of the correct one. In order to realize that, Spitaler must have observed both his Nova 16 and NGC 3526, whence the date listed for his observation.
Physical Information:

Historical Identification: Per Dreyer, NGC 3527 (= GC 2304 = JH 820 = WH III 350, 1860 RA 10 59 41, NPD 60 43.6) is "extremely faint, small, 10th magnitude star 60 arcsec to west". The position precesses to RA 11 07 16.5, Dec +28 31 03, only 0.7 arcmin southwest of the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain.
Physical Information:

Historical Identification: Per Dreyer, NGC 3528 (= GC 2305 = JH 3316, 1860 RA 11 00 17, NPD 108 43.1) is "faint, small, round, pretty suddenly a little brighter middle, preceding (western) of 2", the other being NGC 3529.
Physical Information: Physical Information: Given the duplicate entries, see NGC 3497 for anything else.

Historical Identification: Per Dreyer, NGC 3529 (= GC 2306 = JH 3317, 1860 RA 11 00 20, NPD 108 47.3) is "extremely faint, small, round, very little brighter middle, following (eastern) of 2", the other being NGC 3528.
Physical Information:

Historical Identification: Per Dreyer, NGC 3530 (= GC 2307 = JH 821 = WH III 915, 1860 RA 11 00 21, NPD 32 01.5) is "very faint, small, round, pretty gradually brighter middle".
Physical Information:

Historical Identification: Per Dreyer, NGC 3531 (Holden (#3), 1860 RA 11 00 22, NPD 82 32.5) is "extended 50°, 11th magnitude star at southwestern end (equal to (GC) 5546?)" 5546 being NGC 3526, so Dreyer suspected right from the start that NGC 3531 was a duplicate of Marth's observation. This was confirmed in the first IC, which adds "to be struck out, is = 3526 (per Spitaler)", so the identity of the two listings has been known for more than a century.
Discovery Notes: In a discussion of his Nova 16 (observed Mar 7, 1891), which became IC 670, Spitaler states that it is not NGC 3531, and that Holden actually observed NGC 3526, but used the wrong reference star (namely, he mistook BD+7°.2412 for BD+7°.2413), thereby obtaining a position too far to the east of the correct one. In order to realize that, Spitaler must have observed both his Nova 16 and NGC 3526, whence the date listed for his observation.
Physical Information: Given the duplicate entry, see NGC 3526 for anything else.

Historical Identification: Per Dreyer, NGC 3532 (= GC 2308 = JH 3315, Lacaille II.10, Dunlop 323, 1860 RA 11 00 34, NPD 147 55.0) is "A very remarkable object, a cluster, extremely large, round, a little compressed, stars from 8th to 12th magnitude". (Herschel's position appears to have been based on that of the brightest star, at RA 11 06 29, Dec -58 40.4.)
PGC Designation Note: As usual for NGC objects, HyperLEDA assigned a PGC designation to this object, even though it isn't a galaxy; but also as usual in such cases, a search of the database for that designation returns no result, so it is shown in quotes.
Physical Information: TBA ASAP

Historical Identification: Per Dreyer, NGC 3533 (= GC 2309 = JH 3318, 1860 RA 11 00 45, NPD 126 25.0) is "most extremely faint, very small (faint) star attached".
Non-Standard Designation Warning: The use of "letter" additions to NGC/IC numbers should always be avoided, as there is no system for assigning such letters, and the same letters are often assigned to different objects, causing disastrous confusion in later observations. In this case, in particular, there is a perfectly good NGC designation already available, so the designation "NGC 3557A" is especially noxious.
Physical Information:

Historical Identification: Per Dreyer, NGC 3534 (= GC 5547, Otto Struve, 1860 RA 11 01 08, NPD 62 37) is "very faint, 9th magnitude star 3 arcmin to northwest".
Physical Information:

Non-Standard Designation Warning: The use of "letter" additions to NGC/IC numbers should always be avoided, as there is no system for assigning such letters, and the same letters are often assigned to different objects, causing disastrous confusion in later observations.
Physical Information: Despite appearing to be a possible companion of NGC 3534, it is nearly twice as far away, so they are merely an optical double.

Historical Identification: Per Dreyer, NGC 3535 (= GC 2310 = JH 823 = WH III 111, 1860 RA 11 01 17, NPD 84 24.8) is "considerably faint, very small, round, brighter middle, mottled but not resolved".
Physical Information:

Historical Identification: Per Dreyer, NGC 3536 (= GC 2311 = JH 822, 1860 RA 11 01 19, NPD 60 47.2) is "faint, small, round, brighter middle".
Physical Information:

Historical Identification: Per Dreyer, NGC 3537 (Tempel list I (#30) & list V (#8/9), Common, 1860 RA 11 01 25, NPD 99 30.1) is "very faint, small, very faint star involved". The position precesses to RA 11 08 27.5, Dec -10 15 32, right on the pair of galaxies listed above, the description fits and there is nothing else nearby, so the identification is certain.
Designation Note: Although LEDA lists the individual PGC designations without any problem, a search of the database for the PGC designation for the pair returns no result, so it is listed in quotes. Also, Donald Pelletier points out that SIMBAD lists this as PGC 33759; but that is a blunder, as PGC 33759 is NGC 3541.
Physical Information:

Historical Identification: Per Dreyer, NGC 3538 (= GC 5548, d'Arrest, 1860 RA 11 01 28, NPD 13 40.6) is "very faint, pretty large, 17th magnitude star near".
Physical Information:

Historical Identification: Per Dreyer, NGC 3539 (= GC 2312 = JH 825, 1860 RA 11 01 31, NPD 60 34.5) is "extremely faint". The position precesses to RA 11 09 05.8, Dec +28 40 03, only 0.7 arcmin west southwest of the galaxy listed above and there is nothing else nearby, so the identification is certain.
Physical Information: Based on a recessional velocity of 9705 km/sec, a straightforward calculation indicates that NGC 3539 is about 450 million light years away. However, for objects at such distances we should take into account the expansion of the Universe during the time it took their light to reach us. Doing that shows that the galaxy was about 435 million light years away at the time the light by which we see it was emitted, about 440 million years ago (the difference between the two numbers being due to the expansion of the intervening space during the light-travel time). Given that and its apparent size of 1.1 by 0.25 arcmin, the galaxy is about 140 thousand light years across.

Historical Identification: Per Dreyer, NGC 3540 (= GC 2313 = JH 824, 1860 RA 11 01 32, NPD 53 12.7) is "very faint, round, pretty suddenly brighter middle, 7th magnitude star 7 arcmin to west".
Physical Information:

Historical Identification: Per Dreyer, NGC 3541 (Common, (Tempel list I #31), 1860 RA 11 01 41, NPD 100 00) is a "nebulous star".
Discovery Notes: Dreyer apparently did not know about Tempel's prior observation, so it is included in the NGC entry in parentheses.
Designation Note: SIMBAD incorrectly lists this as PGC 33772.
Physical Information:

Physical Information: Note to self: Contact Corwin about GAIA2 data.

Historical Identification: Per Dreyer, NGC 3542 (Stephan list XIII (#60), 1860 RA 11 02 13, NPD 52 17.7) is "very faint, small, irregularly round, a little brighter middle, mottled but not resolved".
Physical Information:

Historical Identification: Per Dreyer, NGC 3543 (= GC 2314 = JH 826 = WH III 920, 1860 RA 11 02 29, NPD 27 54.0) is "extremely faint, very small, extended 0°±, mottled but not resolved".
Physical Information:

Historical Identification: Per Dreyer, NGC 3544 (Ormond Stone list I (#184), 1860 RA 11 02 30, NPD 107 31.3) is "very faint, large, much extended 95°, brighter middle, equal to (WH) II 819?", II 819 being NGC 3571, so Stone's suspicion about the duplicate entry (stated in his notes as "G.C. 2330?") proved correct.
Discovery Notes: Despite Stone's (and Dreyer's) suspicion that his "nova" was a duplicate of Herschel's prior discovery, the fact that current usage generally assigns the lower NGC number to objects means that this object is almost always referred to as NGC 3544.
Physical Information:

Historical Identification: Per Dreyer, NGC 3545 (Stephan list XIII (#61), 1860 RA 11 02 30, NPD 52 16.1) is "very faint, very small, irregularly round, a little brighter middle, mottled but not resolved".
Warning About Non-Standard Designations: The designations "NGC 3545A" and "NGC 3545B" for this galaxy are shown only because those terms are also used (in various references) for another galaxy (discussed in the following entry), and shows how using non-standard letter designations for NGC/IC objects can lead to confusion, and sometimes result in data obtained for one galaxy being incorrectly assigned to another. As a result, such non-standard designations should never be used.
Physical Information:

Warning About Non-Standard Designations: Attaching non-standard "letter" designations to NGC/IC designations is an abomination. This example is a particularly egregious one, as can be seen in the entry for NGC 3545, which is also sometimes designated as NGC 3545A (and at other times as NGC 3545B!). Such a situation can only lead to confusion, so such non-standard usage should never be allowed. The purpose of this entry is to serve as a warning, in case someone is misled into believing that PGC 33893 deserves any kind of NGC appellation.
Physical Information:

Historical Identification: Per Dreyer, NGC 3546 (Muller list II (#432), 1860 RA 11 02 30, NPD 102 38.3) is a "nebulous 12th magnitude star, with another 12th magnitude star 2 arcmin to the northeast". The second IC lists a corrected RA (per Ormond Stone and Herbert Howe) of 11 02 47. (Howe's paper states that the position was 1900 RA 11 04 47, Dec -12 50.1, which corresponds to 1860 RA 11 02 47.1, NPD 102 37 08.)
Physical Information:

Historical Identification: Per Dreyer, NGC 3547 (= GC 2315 = JH 828 = WH II 42, 1860 RA 11 02 39, NPD 78 31.0) is "faint, small, a little extended, very little brighter middle".
Physical Information:

Historical Identification: Per Dreyer, NGC 3548 (= GC 2316 = JH 827, 1860 RA 11 02 41, NPD 53 12.6) is "extremely faint, small, 8th magnitude star to west".
Physical Information: Given the duplicate entry, see NGC 3540 for anything else.

Historical Identification: Per Dreyer, NGC 3549 (= GC 2317 = WH I 220, 1860 RA 11 02 45, NPD 35 51.8) is "considerably bright, considerably large, considerably extended 160°".
Physical Information: