Historical Identification: Per Dreyer, NGC 1500 (= GC 800 = JH 2603, Dunlop 369?, 1860 RA 03 54 34, NPD 142 43.6) is "faint, very small, round, pretty much brighter middle, 8th magnitude star to northwest".
Discovery Notes: Although Herschel and therefore Dreyer tentatively identified this object with Dunlop's #369, even the most thorough modern compilation of Dunlop's observations fails to identify Dunlop 369 with any celestial object; so whatever that observation represented, it appears it was not NGC 1500.
Physical Information: Apparent size of about 1.6 by 1.2 arcmin (from the images below).

Historical Identification: Per Dreyer, NGC 1501 (= GC 801 = WH IV 53, 1860 RA 03 54 59, NPD 29 27.9) is "a planetary, pretty bright, pretty small, very little extended, 1 arcmin diameter". For purposes of completeness, NGC 1501 is listed in LEDA as PGC 3441330 (and as a planetary nebula), but a search of the database for that designation returns no result, so it is shown in quotes.
Physical Information: Apparent size 1.0 by 0.9 arcmin?

Historical Identification: Per Dreyer, NGC 1502 (= GC 802 = WH VII 47, 1860 RA 03 55 10, NPD 28 03.9) is "a cluster, pretty rich, considerably compressed, irregular figure".
Physical Information: Apparent size 15 to 20 arcmin? Listed in LEDA as PGC 3518639 (and as a cluster), but a search of the database for that designation returns no result.

Historical Identification: Per Dreyer, NGC 1503 (= GC 803 = JH 2604, 1860 RA 03 55 25, NPD 156 25.7) is "extremely faint, pretty small, round, 10th magnitude star to northwest".
Physical Information: Apparent size 0.9 by 0.7 arcmin?

Historical Identification: Per Dreyer, NGC 1504 (Ormond Stone list I (#120), 1860 RA 03 55 35, NPD 99 43.2) is "extremely faint, small, round, gradually brighter middle".
Physical Information: The 9750 km/sec recessional velocity of NGC 1504 is nearly identical to that for NGC 1505, so the two galaxies are probably a physical pair about 440 million light years away from us (as discussed in the entry for NGC 1505), and depending upon their radial separation, should be only a few hundred thousand to a few million light years apart. Given that and its apparent size of 0.75 by 0.7 arcmin(?), NGC 1504 is about 95 thousand light years across.

Historical Identification: Per Dreyer, NGC 1505 (Ormond Stone list I (#121), 1860 RA 03 55 35, NPD 99 42.2) is "extremely faint, small, round, gradually brighter middle".
Physical Information: Based on a recessional velocity of 9765 km/sec, a straightforward calculation indicates that NGC 1505 is about 455 million light years away. However, for objects at such distances we should take into account the expansion of the Universe during the time it took their light to reach us. Doing that shows that the galaxy was about 440 million light years away at the time the light by which we see it was emitted, about 455 million years ago (the difference between the two numbers being due to the expansion of the intervening space during the light-travel time). Given that and its apparent size of 1.2 by 0.95 arcmin(?), the galaxy is about 155 thousand light years across. As noted in the entry for NGC 1504, the nearly identical recessional velocities of the two galaxies probably means that they are a physical pair, and depending upon their radial separation, shoud be only a few hundred thousand to a few million light years apart.

Historical Identification: Per Dreyer, NGC 1506 (= GC 804 = JH 2605, 1860 RA 03 56 45, NPD 142 58.1) is "very most extremely faint, small, round, between 2 stars of magnitude 12 and 13".
Physical Information: Apparent size 1.7 by 1.1 arcmin?

Historical Identification: Per Dreyer, NGC 1507 (= GC 805 = WH II 279, 1860 RA 03 57 20, NPD 92 35.0) is "very faint, pretty large, much extended, a very little brighter middle, extremely mottled but not resolved".
Physical Information: Based on a recessional velocity of 865 km/sec, NGC 1507 is about 40 million light years away, in good agreement with redshift-independent distance estimates of 33 to 43 million light years. Given that and its apparent size of 3.9 by 1.0 arcmin(?), it is about 45 thousand light years across.

Historical Identification: Per Dreyer, NGC 1508 (= GC 5333, Stephan list VIII (#14), 1860 RA 03 57 21, NPD 64 58.6) is "very faint, very small, round, brighter middle, mottled but not resolved".
Physical Information: Based on a recessional velocity of 7160 km/sec, a straightforward calculation indicates that NGC 1508 is about 330 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 325 million light years away at the time the light by which we see it was emitted, just under 330 million years ago (the difference between the two numbers being due to the expansion of the intervening space during the light-travel time). Given that and its apparent size of 1.2 by 0.8 arcmin(?)(, it is about 115 thousand light years across.

Historical Identification: Per Dreyer, NGC 1509 (Swift list V (#59), Ormond Stone list I (#122), 1860 RA 03 57 29, NPD 101 33.8) is "very faint, very small, a little extended, faint star near to west". The position precesses to RA 04 04 06.6, Dec -11 10 33, which is about 2.8 arcmin nearly due east of the galaxy listed above. This error was large enough that when Bigourdan looked for NGC 1509 he found nothing at its supposed location, and thought that the galaxy listed above was a 'nova', hence its duplicate entry as IC 2026; but the description fits and there is nothing else in the region that could possibly be the object observed by Swift and Stone, so there is no doubt that what they observed was the same galaxy.
Discovery Notes: PGC 14389 is shown in the images below because it is sometimes misidentified as IC 2026 (which is actually a duplicate entry for NGC 1509), and given that is mentioned in the discussion of the IC entry. It is also possible that PGC 14389 is a companion of NGC 1509, though whether they are reasonably close companions is even more uncertain.
Discovery Information: Stone's paper was sent to the Astronomical Journal on October 12, 1886, so all the observations listed there must have been completed before that date; but since the paper wasn't actually in print at the time of Swift's observation, he did make an independent discovery of the object.
Physical Information: Based on a recessional velocity relative to the Cosmic Background Radiation of 8495 km/sec (and H₀ = 70 km/sec/Mpc), a straightforward calculation indicates that NGC 1509 is about 395 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 380 to 385 million light years away at the time the light by which we see it was emitted, about 385 to 390 million years ago (the difference between the two numbers being due to the expansion of the intervening space during the light-travel time). Given that and its apparent size of 0.75 by 0.55 arcmin (from the images below), it is about 80 to 85 thousand light years across.

Historical Identification: Per Dreyer, NGC 1510 (= GC 806 = JH 2606, 1860 RA 03 59 00, NPD 133 47.6) is "faint, pretty large, round, very gradually much brighter middle." The position precesses to RA 04 03 35.5, Dec -43 24 26, just over 0.6 arcmin southeast of the galaxy listed above, the description fits and (per Gottlieb) Herschel's original notes specifically state that it is a companion to Dunlop 466 (= NGC 1512), which is the only other object in the region, so the identification is certain.
Physical Information: Given the images below and their nearly identical recessional velocities, NGC 1510 and 1512 must be a physically interacting pair, which means they must be at the same distance from us. The entry for NGC 1512 contains a detailed discussion of how that distance can be estimated, yielding a distance of about 40 million light-years for the pair. Given that and its apparent size of about 1.8 by 1.7 arcmin (from the images below), NGC 1510 is about 20 thousand light-years across.
Use By The deVaucouleurs Atlas: NGC 1510 is used by The deVaucouleurs Atlas of Galaxies as an example of type SA(s)0/a pec. However, the image in that atlas is not nearly as good as the ones shown below, which show a partial ring on the southwestern side of the galaxy, and a probable combination of both ring and spiral features in its nucleus, so the type shown in the description line has been slightly altered to reflect that (albeit with the addition of a question mark, since even the images below would benefit from more detail).

Historical Identification: Per Dreyer, NGC 1511 (= GC 807 = JH 2608, 1860 RA 03 59 03, NPD 158 01.4) is "pretty bright, pretty small, much extended 121.5°, gradually brighter middle".
Physical Information: Based on a recessional velocity of 1340 km/sec, NGC 1511 is about 60 million light years away, in good agreement with redshift-independent distance estimates of 50 to 60 million light years. A second recessional velocity measurement of only 1000 km/sec corresponds to a little over 45 million light years, and in the absence of any certainty about a particular measurement's accuracy, all that can be said is that the galaxy is more likely to be between 50 and 60 million light years away than not. Given that and its apparent size of 3.9 by 1.3 arcmin(?), it is about 60 thousand light years across. NGC 1511 shares a similar recessional velocity with two nearby galaxies, PGC 14255 and PGC 14279, and it is thought that the three represent a physical group. Used by the de Vaucouleurs Atlas of Galaxies as an example of galaxy type SB(s)dm: pec sp.

Physical Information: Based on a recessional velocity of 1340 km/sec, PGC 14255 is about 60 million light years away, in good agreement with redshift-independent distance estimates of 50 to 75 million light years. As for NGC 1511 (which see), there is also a second recessional velocity (of only 985 km/sec) that implies a distance of only 45 million light years, and as for that galaxy the general consensus is that it is in the range of 50 to 60 million light years away, rather than at any smaller distance. Given that and its apparent size of 1.6 by 0.35 arcmin(?), it is about 25 thousand light years across. Because of its nearly edge-on orientation and the low quality of available images, the type is uncertain, being listed as SB0, SBa and SBab in various references. PGC 14255 is thought to be part of a physical group with NGC 1511 as the main component, and PGC 14255 as another minor component.

Physical Information: Based on a recessional velocity of 1305 km/sec, PGC 14279 is about 60 million light years away. Given that and its apparent size of 2.0 by 0.2 arcmin(?), it is about 35 thousand light years across. Because of its nearly edge-on orientation and the low quality of available images, the type is uncertain. As stated in the entries immediately above, PGC 14279 is thought to be part of a physical group with NGC 1511 as the main component, and PGC 14255 as another minor component, in which case it is probably a little closer than implied by its recessional velocity.

Historical Identification: Per Dreyer, NGC 1512 (= GC 808, JH 2607, Dunlop 466, 1860 RA 03 59 20, NPD 133 44.4) is "a globular cluster, bright, considerably large, round, brighter middle, partially resolved, some stars seen." The second IC adds (per DeLisle Stewart) "Not a globular cluster, but an extremely faint ring nebula." The position precesses to RA 04 03 55.6, Dec -43 21 18, which is within the bright central ring of the galaxy, and Stewart's description makes the identity certain.
Additional Note: Per Gottlieb, Dunlop described this as a nebula, and Turner made a sketch of the galaxy using the 48-inch Great Melbourne Telescope, noting that "it has all the appearance of an ordinary nebula, round and much brighter in the centre." Like almost all observations made with the GMT, neither the sketch nor the notes were ever published; but it does show that Herschel's incorrect description of it as a globular cluster could have been corrected in the original NGC, instead of two decades later, if European astronomers had not distrusted observations made at Melbourne after Dunlop made some critical errors involving other objects, thereby discouraging later Melbourne observers from publishing their observations.
Physical Information: Given the images below and their nearly identical recessional velocities, NGC 1510 and 1512 must be a physically interacting pair, which means they must be at the same distance from us. For NGC 1510, the recessional velocity relative to the Cosmic Microwave Background radiation is 865 km/sec, while for NGC 1512, the recessional velocity is 850 km/sec. Using their average recessional velocity of 855 to 860 km/sec (and H₀ = 70 km/sec/Mpc), the pair should be about 40 million light-years away, in good agreement with redshift-independent distance estimates of about 30 to 40 million light-years for NGC 1510, and about 30 to 50 million light-years for NGC 1512. Given that and its apparent size of about 8.0 by 5.3 arcmin for the bright central galaxy and its reasonably bright outer regions and about 15 by 15 arcmin for the much fainter outer regions (from the images below), the central portion of NGC 1512 is about 90 to 95 thousand light-years across, and its outer regions span about 175 thousand light-years.
Use By The deVaucouleurs Atlas: NGC 1512 is used by The deVaucouleurs Atlas of Galaxies as an example of type (R')SB(r)ab pec. The "type" is a reasonable description of those parts of the galaxy that are more or less normal, and "pec" takes care of the numerous complexities presumably caused by its interaction with NGC 1510.

Historical Identification: Per Dreyer, NGC 1513 (= GC 809 = WH VII 60, 1860 RA 03 59 36, NPD 40 51.8) is "a cluster, large, very rich, pretty compressed, stars very large", 'stars very large' meaning very bright.
Physical Information: Apparent size about 10 arcmin? Listed in LEDA as PGC 3517888 (and as a cluster), but a search of the database for that designation returns no result.

Historical Identification: Per Dreyer, NGC 1514 (= GC 810 = JH 311 = WH IV 69, 1860 RA 04 00 30, NPD 59 35.9) is a "9th magnitude star in a 3 arcmin diameter nebula". For purposes of completeness, NGC 1514 is listed in LEDA as PGC 2882948 (and as a planetary nebula), but a search of the database for that designation returns no result, so the designation is shown in quotes.
Physical Information: Apparent size 3.3 by 3.1 arcmin for the outermost region, 2.4 by 2.1 arcmin for the brighter inner region.

Historical Identification: Per Dreyer, NGC 1515 (= GC 811 = JH 2609, Dunlop 348, 1860 RA 04 00 39, NPD 144 29.4) is "bright, large, very much extended 10°, brighter middle".
Physical Information: Based on a recessional velocity of 1175 km/sec, NGC 1515 is about 55 million light years away, in good agreement with redshift-independent distance estimates of 45 to 65 million light years. Given that and its apparent size of 6.0 by 1.35 arcmin, it is about 95 thousand light years across. NGC 1515 appears to be paired with PGC 14388, but that galaxy is more than ten times farther away, so they are merely an optical double.

Physical Information: Based on a recessional velocity of 13125 km/sec, a straightforward calculation indicates that PGC 14388 is about 610 million light years away. However, for objects at such distances we should take into account the Universal expansion during the time it took their light to reach us. Doing that shows that the galaxy was about 580 million light years away at the time the light by which we see it was emitted, about 595 million years ago (the difference between the two numbers being due to the expansion of the intervening space during the light-travel time). (NED lists a redshift-independent distance estimate of 55 million light years, but that must be a misplaced value for NGC 1515.) Given that and its apparent size of 1.2 by 0.9 arcmin, PGC 14388 is about 200 thousand light years across. Although an apparent pair with NGC 1515, PGC 14388 is more than ten times farther away, so they are merely an optical double.

Historical Identification: Per Dreyer, NGC 1516 (= GC 812 = JH 2610 = WH III 499, 1860 RA 04 01 24, NPD 99 12.4) is "most extremely faint, small, extended, pretty suddenly much brighter middle, extremely mottled but not resolved".
Discovery Notes: Herschel saw this as a single object, which Dreyer recorded as NGC 1516. Almost exactly a century later Stone saw that it was a pair of nebulae, but made an error in their position, so Dreyer recorded them as NGC 1524 and 1525. If the error had been recognized earlier the individual galaxies would probably always be called NGC 1524 and 1525; but since it took some time to realize the equivalency of the listings, PGC 14515 is often called NGC 1516A (instead of the more proper NGC 1524), and PGC 14516 is often called NGC 1516B (instead of the more proper NGC 1525). NGC 1516 is listed in LEDA as PGC 5067395 (and as a galaxy), but a search of the database for that designation returns no result; however, the individual galaxies are listed with valid PGC designations, as shown above and at their individual entries.
Physical Information: Based on an average recessional velocity of 9905 km/sec (9945 km/sec for PGC 15415 and 9865 km/sec for PGC 15416), a straightforward calculation indicates that NGC 1516 is about 460 million light years away. However, for objects at such distances we should take into account the Universal expansion during the time it took their light to reach us. Doing that shows that the galaxy was about 445 million light years away at the time the light by which we see it was emitted, about 450 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 PGC 14515's apparent size of 0.65 by 0.5 arcmin, it is about 85 thousand light years across, and PGC 14516's apparent size of 0.65 by 0.65 arcmin corresponds to the same 85 thousand light years. (The quoted sizes include fainter outlying areas shown in the images below; NED only lists the apparent size of the bright cores, while LEDA lists larger sizes than can be justified by the images.) Given the poor quality of the images below (which are still the best available), the galaxy types listed above seem more specific than reasonably credible, so a better type for each member of the pair might be simply S? pec.

Historical Identification: Per Dreyer, NGC 1517 (Stephan list XIII (#25), 1860 RA 04 01 37, NPD 81 43.6) is "very faint, very small, round, mottled but not resolved, 9th or 10th magnitude star to southeast".
Physical Information: Based on a recessional velocity of 3485 km/sec, NGC 1517 is about 160 million light years away. Given that and its apparent size of 0.85 by 0.75 arcmin, it is about 40 thousand light years across.

Historical Identification: Per Dreyer, NGC 1518 (= GC 813 = JH 2611, 1860 RA 04 01 44, NPD 111 33.0) is "bright, large, pretty much extended, gradually brighter middle, 8th magnitude star to southwest". The second IC adds (per Howe) "Minute of RA is 00, not 01".
Physical Information: Based on a recessional velocity of 920 km/sec, NGC 1518 is about 40 million light years away, in reasonable agreement with redshift-independent distance estimates of 25 to 40 million light years. Given that and its apparent size of 3.8 by 1.35 arcmin, it is about 45 thousand light years across.

Historical Identification: Per Dreyer, NGC 1519 (Tempel lists I (#14) and V (#2), 1860 RA 04 01 50, NPD 107 34.1) is "very faint, small, a little extended, very small star involved", 'very small star' meaning very faint star.
Physical Information: Based on a recessional velocity of 1835 km/sec, NGC 1517 is about 90 million light years away, in reasonable agreement with redshift-independent distance estimates of 65 to 85 million light years. Given that and its apparent size of 2.2 by 0.5 arcmin, it is about 55 thousand light years across.

Historical Identification: Per Dreyer, NGC 1520 (= GC 814 = JH 2615, 1860 RA 04 02 08, NPD 167 13.0) is "a cluster, pretty large, a little rich, stars of 9th to 10th magnitude".
Physical Information: Apparent size about 4.5 arcmin? Listed in LEDA as PGC 3070076 (and as the star HD 25864), but a search of the database for that designation returns no result.

Historical Identification: Per Dreyer, NGC 1521 (= GC 815 = JH 2612, 1860 RA 04 02 10, NPD 111 25.6) is "pretty bright, round, brighter middle".
Physical Information: Based on a recessional velocity of 4245 km/sec, NGC 1521 is about 200 million light years away, in good agreement with redshift-independent distance estimates of 135 to 220 million light years. Given that and its apparent size of 2.7 by 2.0 arcmin, it is about 155 thousand light years across.

Historical Identification: Per Dreyer, NGC 1522 (= GC 816 = JH 2613, 1860 RA 04 02 35, NPC 143 02.7) is "extremely faint, very small, round, very little brighter middle".
Physical Information: Based on a recessional velocity of 900 km/sec, NGC 1522 is about 40 million light years away (a second velocity measurement of 700 km/sec would imply a distance of less than 35 million light years). Given that and its apparent size of 1.3 by 0.9 arcmin, the galaxy is about 15 thousand light years across (or a little less, if the lower velocity and distance are correct).

Historical Identification: Per Dreyer, NGC 1523 (= GC 817 = JH 2614, 1860 RA 04 02 48, NPD 144 28.6) is "very faint, round". The second IC adds (per DeLisle Stewart) "Only 3 very faint stars, not a nebula". Listed in LEDA as PGC 5067591 (and as a group of stars), but a search of the database for that designation returns no result.

Historical Identification: Per Dreyer, NGC 1524 (Ormond Stone list I (#123), 1860 RA 04 03 35, NPD 99 09.9) is "extremely faint, pretty small, round, gradually brighter middle, part of a double nebula with NGC 1525, separated by 0.5 arcmin at a position angle of 340°".
Physical Information: Given the more or less duplicate entry, see NGC 1516 for anything else.

Historical Identification: Per Dreyer, NGC 1525 (Ormond Stone list I (#124), 1860 RA 04 03 35, NPD 99 09.9) is "extremely faint, pretty small, round, gradually brighter middle, part of a double nebula with NGC 1524, separated by 0.5 arcmin at a position angle of 340°".
Physical Information: Given the more or less duplicate entry, see NGC 1516 for anything else.

Historical Identification: Per Dreyer, NGC 1526 (= GC 818 = JH 2617, 1860 RA 04 04 09, NPD 156 12.6) is "extremely faint, very small, round, gradually a little brighter middle".
Physical Information: Based on a recessional velocity of 5335 km/sec, NGC 1526 is about 250 million light years away. Given that and its apparent size of 0.85 by 0.5 arcmin, it is about 60 thousand light years across.

Historical Identification: Per Dreyer, NGC 1527 (= GC 819 = JH 2616, 1860 RA 04 04 18, NPD 138 15.9) is "pretty bright, pretty small, extended 77°, very suddenly much bright middle and round nucleus".
Physical Information: Based on a recessional velocity of 1210 km/sec, NGC 1527 is about 55 million light years away, in good agreement with redshift-independent distance estimates of 35 to 60 million light years. Given that and its apparent size of 5.1 by 1.8 arcmin, it is about 85 thousand light years across. Used by the de Vaucouleurs Atlas of Galaxies as an example of galaxy type SAB0^-.

Historical Identification: Per Dreyer, NGC 1528 (= GC 820 = WH VII 61, 1860 RA 04 04 37, NPD 39 07.2) is "a cluster, bright, very rich, considerably compressed".
Physical Information: Apparent size about 18 arcmin? Listed in LEDA as PGC 3517889 (and as an unknown type of object), but a search of the database for that designation returns no result.

Historical Identification: Per Dreyer, NGC 1529 (= GC 821 = JH 2619, 1860 RA 04 05 33, NPD 153 16.1) is "very faint, small, round, gradually brighter middle".
Physical Information: Apparent size 1.15 by 0.25 arcmin.

Historical Identification: Per Dreyer, NGC 1530 (= GC 5334, Tempel list I (#15), 1860 RA 04 05 42, NPD 15 03.2) is "pretty bright, large".
Physical Information: Based on a recessional velocity of 2460 km/sec, NGC 1527 is about 115 million light years away, in good agreement with redshift-independent distance estimates of 60 to 120 million light years. Given that and its apparent size of 4.6 by 2.5 arcmin, it is about 155 thousand light years across. Used by the de Vaucouleurs Atlas of Galaxies as an example of galaxy type SB(rs)b.

Non-Standard Designation: PGC 15917 is IC 381, but it is sometimes incorrectly called NGC 1530A, hence its inclusion here. It is an example of an extreme mis-use of non-standard NGC designations, in that it has a perfectly good IC designation that should always be used.
Physical Information: Given the galaxy's IC designation, see IC 381 for anything else.

Historical Identification: Per Dreyer, NGC 1531 (= GC 822 = JH 2620, 1860 RA 04 06 35, NPD 123 12.6) is "pretty bright, pretty large, round, brighter middle, northwestern of 2", the other being NGC 1532.
Physical Information: Based on a recessional velocity of 1170 km/sec, NGC 1531 is about 55 million light years away, in fair agreement with a single redshift-independent distance estimate of 42 million light years. It is part of a double system with NGC 1532, suggesting a common distance of around 50 million light years. Given that and its apparent size of 1.5 by 0.8 arcmin, it is about 20 thousand light years across. Over time the gravitational interaction of the two galaxies will probably tear the smaller galaxy apart and merge its remains with the larger one. Their interaction has already torn huge plumes of material from each galaxy (particularly the larger), and generated bursts of star-formation in and near each of them. Used by the de Vaucouleurs Atlas of Galaxies as an example of galaxy type SB0 pec / I0 pec.

Historical Identification: Per Dreyer, NGC 1532 (= GC 823 = JH 2621, Dunlop 600, 1860 RA 04 06 40, NPD 123 14.1) is "bright, very large, very much extended 32°, pretty suddenly much brighter middle".
Physical Information: Based on a recessional velocity of 1040 km/sec, NGC 1532 is about 50 million light years away, in good agreement with redshift-independent distance estimates of 45 to 62 million light years. NGC 1532 is part of a double system with NGC 1531, suggesting a common distance of around 50 million light years. Given that and its apparent size of 12.6 by 3.3 arcmin, it is about 180 thousand light years across. Over time the gravitational interaction of the two galaxies will tear the smaller galaxy apart and merge its remains with the larger one. As it is, their interaction has thrown huge plumes of material away from each galaxy (particularly the larger), and generated bursts of star-formation (the red-purplish regions glowing with the heat of the new stars) in each galaxy. Used by the de Vaucouleurs Atlas of Galaxies as an example of galaxy type SB(s)b pec sp.

Historical Identification: Per Dreyer, NGC 1533 (= GC 824 = JH 2622, 1860 RA 04 06 51, NPD 146 29.3) is "very bright, very large, round, suddenly much brighter middle, 2 stars of magnitude 10 to northeast".
Physical Information: Based on a recessional velocity of 790 km/sec, NGC 1533 is about 37 million light years away, in fair agreement with redshift-independent distance estimates of 44 to 70 million light years. This may mean that the redshift-independent estimates are too large and the galaxy is closer to 40 million light years away, or that it just happens to have a motion toward us relative to the galaxies in its vicinity of 150 or more km/sec (which would not be that unusual), and is somewhat further away than its reduced radial velocity would imply. All we can say is that it is more likely to be between 40 and 50 million light years away than not. Given that and its apparent size of about 3.05 by 2.75 arcmin (from the images below), it is about 35(?) thousand light years across. Used by the de Vaucouleurs Atlas of Galaxies as an example of galaxy type (RL)SB0°.

Historical Identification: Per Dreyer, NGC 1534 (= GC 825 = JH 2623, 1860 RA 04 07 00, NPD 153 09.4) is "faint, small, round, very small star 3/4 of a degree to southeast".
Physical Information: Apparent size of about 1.7 by 0.75 arcmin (from the images below).

Historical Identification: Per Dreyer, NGC 1535 (= GC 826 = JH 2618 = WH IV 26, 1860 RA 04 07 44, NPD 103 05.8) is "a planetary nebula, very bright, small, round, pretty suddenly or very suddenly brighter middle, mottled but not resolved". For purposes of completeness, LEDA lists NGC 1535 as PGC 3517751 (and as a planetary nebula), but a search of the database for that designation returns no result, so the designation is shown in quotes.
Physical Information: Apparent size of about 1.2 by 1.1 arcmin for the very faint outer ring, and of about 0.85 by 0.75 arcmin for the brighter inner ring (from the images below).

Historical Identification: Per Dreyer, NGC 1536 (= GC 827 = JH 2625, 1860 RA 04 08 04, NPD 146 50.4) is "very faint, round, pretty large, very little brighter middle".
Physical Information: Based on a recessional velocity of 1215 km/sec, NGC 1536 is about 55 million light years away, in reasonable agreement with a single redshift-independent distance estimate of 45 million light years. Given that and its apparent size of 2.1 by 1.5 arcmin(?), it is about 30 thousand light years across.

Historical Identification: Per Dreyer, NGC 1537 (= GC 828 = JH 2624, 1860 RA 04 08 18, NPD 121 54.7) is "very bright, pretty small, a little extended, pretty suddenly very much brighter middle".
Physical Information: Based on a recessional velocity of 1430 km/sec, NGC 1536 is about 65 million light years away, in good agreement with redshift-independent distance estimates of 45 to 75 million light years. Given that and its apparent size of about 4.8 by 3.3 arcmin, it is about 90 thousand light years across. Used by the de Vaucouleurs Atlas of Galaxies as an example of galaxy type SAB0^- or E5 (twist).

Historical Identification: Per Dreyer, NGC 1538 (= Ormond Stone list I (#125), 1860 RA 04 08 35, NPD 103 35.6) is "extremely faint, very small, round, gradually brighter middle". The position precesses to RA 04 15 05.5, Dec -13 14 20, which is near the outline of the brighter of two faint galaxies (PGC 940994 and PGC 3093623). Under normal circumstances this would be considered reasonably accurate, and the identification of NGC 1538 as PGC 3093623 relatively certain. And in fact when Howe observed the area in 1900 he presumed that what is now called PGC 3093623 was Stone's NGC 1538 and according to Corwin, Reinmuth agreed with that assessment in 1928; so this identification of NGC 1538 was considered correct for a long time. But in recent years the identification has been called into question, and NGC 1538 is now more commonly identified as one of two other galaxies observed by Howe, as noted above. The reason for this is that Stone's right ascensions were often off by as much as a couple of minutes, so it is possible that his observation was of one of the other galaxies in the area, and if so the most logical assumption is that it was the brightest one (which is IC 2045). However, Stone's sketch of the area suggests that what he actually observed was the next brightest (which is IC 2047). It seems that none of the three galaxies can be definitely deemed correct or ruled out, so it might be best to say that NGC 1538 refers to an unknown galaxy and discuss each suggestion at the appropriate place. For IC 2045 and IC 2047 that is at those entries, since their identification as those objects is not in question; but since PGC 3093623 was considered to be NGC 1538 for many years, its discussion immediately follows this entry. (Note: Perhaps not unsurprisingly given such confusion, Wikisky searches for NGC 1538, IC 2045 and IC 2047 all show IC 2045, labeled as NGC 1538.)
Designation Note: LEDA lists this as PGC 941480, which is IC 2047, but does not list it as an IC object.

Historical Identification: Although listed as NGC 1538 for many decades, that identification is no longer considered certain (refer to NGC 1538).
Physical Information: Based on a recessional velocity of 9080 km/sec, PGC 3093623 is about 420 million light years away (*note to self: in next iteration, use relativistic correction*). Given that and its apparent size of 0.7 by 0.4 arcmin(?), it is about 85 thousand light years across. It appears to be part of a physical pair with the galaxy to its northeast (PGC 940994), as each has a slightly distorted shape presumably caused by their interaction. (Listed in NED as HOLM 073A.)

Physical Information: Based on a recessional velocity of 9205 km/sec, PGC 940994 is about 430 million light years away (*note to self: in next iteration, use relativistic correction*). Given that and its apparent size of 0.45 by 0.4 arcmin(?), it is about 55 thousand light years across. The distorted appearance of each galaxy suggests that it is probably part of a physical pair with PGC 3093623 (which see for images), so despite the different distance estimates caused by their slightly different recessional velocities, they are probably at essentially the same distance from us.

Historical Identification: Per Dreyer, NGC 1539 (= GC 5335, Marth #94, 1860 RA 04 09 25, NPD 63 35) is "very faint, very small, gradually brighter middle". The position precesses to that shown above as 'lost or nonexistent', since there is nothing there. However, Corwin suggests that what Marth saw might be PGC 14852, the only reasonably bright object in the half-degree field of view surrounding Marth's position, as the 1 minute error in right ascension and 4.7 arcmin error in declination are not unusual for Marth's observations, and the description fits. It seems doubtful that anyone can be certain that this is correct, but as long as the object is in question it doesn't hurt to discuss it, so it is covered immediately after this entry.

Historical Identification: See the entry for NGC 1539.
Physical Information: Based on a recessional velocity of 5555 km/sec, PGC 14852 is about 255 to 260 million light years away. Given that and its apparent size of about 1.05 by 0.75 arcmin (from the images below), it is about 80 thousand light years across. Note: Corwin lists a magnitude 16.6 apparent companion of PGC 14852 at RA 04 19 02.7, Dec +26 49 47, which is the position of the star just northeast of PGC 14852's nucleus; so that identification is incorrect (undoubtedly due to the poor quality of earlier images of the galaxy).

Historical Identification: Per Dreyer, NGC 1540 (= GC 829 = JH 2626, 1860 RA 04 09 33, NPD 118 50.3) is "very faint, very small, extended, gradually a very little brighter middle, mottled but not resolved".
Physical Information: Despite the poor quality of the available images, there can be no doubt that NGC 1540 represents the results of a spectacular collision between two galaxies. Unfortunately, NED reverses the order of the PGC listings, so observations that are supposed to refer to one component may have been made for the other. For that reason, their apparent sizes were directly measured from the images below, and type assignments were made partly on the basis of the NED/LEDA listings, and partly from the appearance of those images. Recessional velocities might also be misattributed, but they are all between 5400 and 5500 km/sec, so an average of 5450 km/sec can't be very far off. Based on that, the pair is about 250 million light years away. Given that, PGC 14733's apparent size of 0.75 by 0.45 arcmin corresponds to about 55 thousand light years, and PGC 14734's apparent size of 0.65 by 0.35 arcmin to about 50 thousand light years.

Historical Identification: Per Dreyer, NGC 1541 (= GC 5336, Marth #95, 1860 RA 04 09 48, NPD 89 32) is "very faint, small".
Physical Information: Apparent size of about 1.4 by 0.5 arcmin (from the images below).

Historical Identification: Per Dreyer, NGC 1542 (= GC 5337, Marth #96, 1860 RA 04 09 51, NPD 85 34) is "very faint, small, extended".
Physical Information: Based on a recessional velocity of 3715 km/sec, NGC 1542 is about 170 to 175 million light years away. Given that and its apparent size of about 1.45 by 0.55 arcmin (from the images below), it is about 70 to 75 thousand light years across.

Historical Identification: Per Dreyer, NGC 1543 (= GC 830 = JH 2627, (Dunlop 306), 1860 RA 04 09 59, NPD 148 05.6) is "bright, pretty large, extended, suddenly much brighter middle and nucleus equal to an 11th magnitude star".
Discovery Notes: At the time Dreyer did the NGC it was not realized that Dunlop's #306 was this object, so he did not credit Dunlop with the discovery.
Physical Information: Based on a recessional velocity of 1175 km/sec, NGC 1543 is about 55 million light years away, in good agreement with redshift-independent distance estimates of 44 to 66 million light years. Given that and its apparent size of about 7.3 by 6.6 arcmin (from the images below), its outer ring is about 115 thousand light years across. Used by the de Vaucouleurs Atlas of Galaxies as an example of galaxy type (R)SB(l)0/a.

Historical Identification: Per Dreyer, NGC 1544 (= GC 5338, Tempel list I (#16), 1860 RA 04 10 10, NPD 04 03.3) is "very faint, very small".
Physical Information: Based on a recessional velocity of 3935 km/sec, NGC 1544 is about 180 to 185 million light years away; however, a second velocity measurement of 4515 km/sec implies a distance of 210 million light years. Given that and its apparent size of about 1.15 by 0.65 arcmin (from the images below), it is about 60 thousand light years across if at the smaller distance, and 70 thousand light years across if at the larger distance.

Historical Identification: Per Dreyer, NGC 1545 (= GC 831 = WH VIII 85, 1860 RA 04 10 25, NPD 40 05.7) is "a cluster, pretty rich, a little compressed, stars large" (meaning bright).
Physical Information: Apparent size 12 arcmin? LEDA lists this as PGC 3518640 (and as an unknown type of object), but a search of the database for the designation does not return a result.

Historical Identification: Per Dreyer, NGC 1546 (= GC 832 = JH 2628, 1860 RA 04 11 38, NPD 146 25.0) is "pretty bright, a little extended, gradually brighter middle and extended nucleus, double star to west".
Physical Information: Apparent size of about 3.8 by 2.8 arcmin (from the images below).

Historical Identification: Per Dreyer, NGC 1547 (Leavenworth list I (#126), 1860 RA 04 11 40, NPD 108 13.6) is "pretty faint, pretty small, irregularly round (a cluster or nebula with stars involved?)". The second IC lists a corrected RA (per Howe) of 04 10 57, and (incorrectly) adds "a cluster".
Physical Information: Based on a recessional velocity of 9570 km/sec, NGC 1547 is about 445 million light years away (*Note to self: Need to use relativistic correction*). Given that and its apparent size of about 1.3 by 0.5 arcmin (from the images below), it is about 170(?) thousand light years across.

Historical Identification: Per Dreyer, NGC 1548 (= GC 833 = JH 312, 1860 RA 04 11 46, NPD 53 25.8) is "a cluster, very large, a little rich, a little compressed, stars from 10th to 12th magnitude". Corwin lists RA 04 20 14, Dec +36 26 48 as the best estimate of the position; but also gives RA 04 20 58.9, Dec +36 34 28 for the position of the star used by JH as the position of the group, and RA 04 21 00, RA 36 54 42 as the incorrect position measured by JH for that star.
Physical Information: Apparent size 30 arcmin? LEDA lists this as PGC 5067415 (and as an open cluster), but a search of the database for that designation returns no result.

Historical Identification: Per Dreyer, NGC 1549 (= GC 834 = JH 2629, (Dunlop 331), 1860 RA 04 12 09, NPD 145 55.8) is "bright, pretty small, round". The second IC lists a corrected RA (per Innes and DeLisle Stewart) of 04 12 44 and adds "13 arcmin northwest of h2630 (h's RA only rough)".
Discovery Notes: At the time Dreyer did the NGC it was not known that Dunlop's #331 was this object.
Physical Information: Based on a recessional velocity of 1255 km/sec, NGC 1549 is about 55 to 60 million light years away, in good agreement with redshift-independent distance estimates of 45 to 65 million light years. Given that and its apparent size of about 5.1 by 4.6 arcmin (from the images below), it is about 85 to 90 thousand light years across. The galaxy is a member of the NGC 1566 group. It is part of a possibly gravitationally bound pair with NGC 1553, which is a little over 11 arcminutes away in the sky, and if at a common distance of about 55 million light years may be separated by as little as 175 thousand light years.