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Historical Identification: Per Dreyer, IC 4900 (= Frost #1170, 1860 RA 19 39 38, NPD 141 41) has a "brighter middle, magnitude 15". The position precesses to RA 19 50 19.4, Dec -51 20 19, only half an arcmin northwest of the galaxy listed above, and although there is a similarly bright galaxy (PGC 185799) about 2 arcmin to the southeast of Frost's position, no one has expressed any concern about the identification, so it appears to be certain.
Physical Information: Apparent size 0.8 by 0.2 arcmin. Distance (and therefore actual size) unknown. Possibly binuclear.

Historical Identification: Per Dreyer, IC 4901 (= DeLisle Stewart #618, 1860 RA 19 42 37, NPD 149 04) is "considerably faint, small, very little extended 135°". The position precesses to RA 19 54 23.2, Dec -58 42 40, right on the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 5.0 by 3.5 arcmin.

Historical Identification: Per Dreyer, IC 4902 (= DeLisle Stewart #619, 1860 RA 19 43 02, NPD 146 44) is "most extremely faint, extremely small, considerably extended 0°; suspected". The position precesses to RA 19 54 24.3, Dec -56 22 38, right on the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 0.7 by 0.3 arcmin.

Historical Identification: Per Dreyer, IC 4903 (= DeLisle Stewart #621, 1860 RA 19 43 10, NPD 160 49) is "extremely faint, very small, between 2 faint stars". The position precesses to RA 19 58 11.8, Dec -70 27 16, on the western rim of the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 1.15 by 0.4 arcmin.

Historical Identification: Per Dreyer, IC 4904 (= DeLisle Stewart #622, 1860 RA 19 43 36, NPD 160 33) is "very faint, small, round". The position precesses to RA 19 58 30.5, Dec -70 11 12, just off the western rim of the galaxy listed above and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 1.05 by 0.8 arcmin.

Historical Identification: Per Dreyer, IC 4905 (= DeLisle Stewart #620, 1860 RA 19 43 53, NPD 151 35) is "most extremely faint, extremely small, much extended 130°, near 2 extremely faint stars". The position precesses to RA 19 56 07.7, Dec -61 13 24, on the southeastern end 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 16000 km/sec, a straightforward calculation indicates that IC 4905 is about 745 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 700 million light years away at the time the light by which we see it was emitted, about 720 million years ago (the difference between the two numbers being due to the expansion of the intervening space during the light-travel time). Given that and its apparent size of 1.0 by 0.25 arcmin, the galaxy is about 200 thousand light years across.

Historical Identification: Per Dreyer, IC 4906 (= DeLisle Stewart #623, 1860 RA 19 44 44, NPD 150 49) is "faint, small, round, brighter middle, 4 stars around". The position precesses to RA 19 56 48.8, Dec -60 27 16, just north of the galaxy listed above and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 1.7 by 1.0 arcmin.

Historical Identification: Per Dreyer, IC 4907 (= Frost #1171, 1860 RA 19 45 24, NPD 142 49) has a "brighter middle, magnitude 16". The position precesses to RA 19 56 11.3, Dec -52 27 15, on the western rim of the galaxy listed above and there is nothing else nearby, so the identification is certain.
Physical Information: Based on a recessional velocity of 15055 km/sec, a straightforward calculation indicates that IC 4907 is about 700 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 660 million light years away at the time the light by which we see it was emitted, about 675 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 0.5 by 0.5 arcmin, the galaxy is about 85 thousand light years across.

Historical Identification: Per Dreyer, IC 4908 (= DeLisle Stewart #624, 1860 RA 19 45 41, NPD 146 09) is "extremely faint, extremely small, round, suspected". The position precesses to RA 19 56 56.3, Dec -55 47 10, on the northern rim of the galaxy listed above and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 0.7 by 0.7 arcmin.

Historical Identification: Per Dreyer, IC 4909 (= Frost #1172, 1860 RA 19 46 24, NPD 140 24) has a "brighter middle, magnitude 15". The position precesses to RA 19 56 52.9, Dec -50 02 06, about 1.7 arcmin northeast of the galaxy listed above, but there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size of the central galaxy about 1.1 by 0.55 arcmin; including its extended arms, about 2.4 by 1.0 arcmin.

Historical Identification: Per Dreyer, IC 4910 (= DeLisle Stewart #625, 1860 RA 19 46 26, NPD 147 14) is "extremely faint, extremely small, considerably extended 130°, among stars; suspected". The position precesses to RA 19 57 51.1, Dec -56 52 01, only 0.6 arcmin east southeast of the galaxy listed above, it fits the description and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 0.6 by 0.4 arcmin.

Historical Identification: Per Dreyer, IC 4911 (= Frost #1173, 1860 RA 19 47 02, NPD 142 20) has a "brighter middle, magnitude 16". The position precesses to RA 19 57 44.7, Dec -51 57 58, about 1.3 arcmin north northeast of the galaxy listed above, and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 0.55 by 0.35 arcmin.

Historical Identification: Per Dreyer, IC 4912 (= DeLisle Stewart #628, 1860 RA 19 47 14, NPD 167 44) is "extremely faint, very small, faint star 1 arcmin to northwest; suspected". The position precesses to RA 20 06 43.4, Dec -77 21 08, less than half an arcmin northwest of the galaxy listed above, there is nothing else nearby, and although the 10th magnitude star an arcmin to the northwest isn't as "faint" as might be expected, it makes the identification certain.
Physical Information: Apparent size 1.15 by 0.4 arcmin.

Historical Identification: Per Dreyer, IC 4913 (= Swift list XI (#185), Howe, 1860 RA 19 47 30, NPD 127 41.7) is "most extremely faint, pretty small, extremely difficult, three 10th magnitude stars 8 arcmin to south". Dreyer's position was taken from Howe's paper (hence the double credit for the discovery). It precesses to RA 19 56 47.1, Dec -37 19 43, right on the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 1.3 by 0.9 arcmin.

Historical Identification: Per Dreyer, IC 4914 (= Frost #1174, 1860 RA 19 47 36, NPD 140 29) is "faint, very small, round". The position precesses to RA 19 58 04.9, Dec -50 06 53, about 1.6 arcmin northeast of the galaxy listed above, but there is nothing else nearby, so the identification is considered certain.
Physical Information: Apparent size 0.4 by 0.35 arcmin.

Historical Identification: Per Dreyer, IC 4915 (= Frost #1175, 1860 RA 19 47 42, NPD 143 01) has a "brighter middle, magnitude 15". The position precesses to RA 19 58 29.7, Dec -52 38 51, on the southwestern rim of the galaxy listed above, and although there are numerous other galaxies in the region, none are bright enough for Frost to have noticed, so the identification is certain.
Physical Information: Apparent size 1.15 by 0.75 arcmin.

Historical Identification: Per Dreyer, IC 4916 (= Frost #1176, 1860 RA 19 48 00, NPD 140 38) is "faint, small, round, faint star in middle". The position precesses to RA 19 58 29.8, Dec -50 15 49, about 1.8 arcmin east northeast of the galaxy listed above, but the description fits and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 1.0 by 0.9 arcmin.

Historical Identification: Per Dreyer, IC 4917 (= Frost #1177, 1860 RA 19 48 07, NPD 142 39) has a "brighter middle, magnitude 16". The position precesses to RA 19 58 51.6, Dec -52 16 46, about halfway between the galaxy listed above and half-magnitude fainterPGC 446330, but since Frost did not mention a pair of nebulae he must have only noticed the brighter one, so the identification of the brighter eastern galaxy with IC 4917 is considered certain.
Physical Information: Apparent size 0.7 by 0.65 arcmin. Its distance appears similar to that ofPGC 446330, so they may be a physical pair; but there is no obvious interaction between them, so even if a physical pair they are probably a few million light years apart (as in the case of our galaxy and the Andromeda Galaxy).

Historical Identification: Per Dreyer, IC 4918 (= Frost #1178, 1860 RA 19 48 31, NPD 142 39) has a "brighter middle, magnitude 16". The position precesses to RA 19 59 15.4, Dec -52 16 42, only 0.4 arcmin southeast of the galaxy listed above and there is nothing else nearby, so the identification is certain.
Physical Information: Based on a recessional velocity of 25455 km/sec, a straightforward calculation indicates that IC 4918 is about 1185 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 1075 million light years away at the time the light by which we see it was emitted, about 1120 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 0.35 by 0.25 arcmin, the galaxy is about 110 thousand light years across.

Historical Identification: Per Dreyer, IC 4919 (= DeLisle Stewart #626, 1860 RA 19 48 54, NPD 145 45) is "most extremely faint, extremely small, round, faint star 1 arcmin to east; suspected". The position precesses to RA 20 00 03.8, Dec -55 22 36, about 0.8 arcmin west southwest of the galaxy listed above, and the star to its east, though not terribly faint, makes the identification certain. (Note: Wikisky misidentifies the galaxy asPGC 63958, which is merely a bright region in IC 4919.)
Physical Information: Apparent size 1.5 by 0.7 arcmin.

Misidentified by Wikisky asIC 4919 (which see for anything else), but actually only a star-forming region in that galaxy.

Historical Identification: Per Dreyer, IC 4920 (= Frost #1179, 1860 RA 19 49 16, NPD 143 45) is "very faint, very little extended, little brighter middle". The position precesses to RA 20 00 08.7, Dec -53 22 33, less than half an arcmin north of the galaxy listed above and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 0.55 by 0.35 arcmin.

Historical Identification: Per Dreyer, IC 4921 (= DeLisle Stewart #630, 1860 RA 19 49 23, NPD 158 13) is "very faint, small, round, considerably brighter middle". The position precesses to RA 20 03 18.5, Dec -67 50 15, about 0.7 arcmin south of the galaxy listed above and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 0.65 by 0.35 arcmin.

Historical Identification: Per Dreyer, IC 4922 (= DeLisle Stewart #627, 1860 RA 19 49 58, NPD 130 44) is "very faint, very small, round, suspected". The position precesses to RA 19 59 28.7, Dec -40 21 33 (whence the position above), in a nearly stellar field that gives no hint of what if anything Stewart recorded (per Corwin, most likely a plate defect, as the only galaxies in the region are 17th magnitude or fainter, and well beyond the limits of a one-hour Bruce plate). Given that, IC 4922 is almost certainly lost or nonexistent.

Historical Identification: Per Dreyer, IC 4923 (= Frost #1180, 1860 RA 19 50 12, NPD 143 00) has a "brighter middle, magnitude 14". The position precesses to RA 20 00 58.2, Dec -52 37 24, on the northern rim of the galaxy listed above, and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 1.05 by 0.95 arcmin.

Historical Identification: Per Dreyer, IC 4924 (= DeLisle Stewart #629, 1860 RA 19 50 15, NPD 131 55) is "diffuse (perhaps a defect?)". The position precesses to RA 19 59 51.6, Dec -41 32 29 (whence the position above), in an almost completely stellar field, and the only nebular object (PGC 63949) is too small and too faint for Stewart to have noticed on a one-hour Bruce plate. So it appears that Stewart's supposition that the "object" might be merely a plate defect was correct, and IC 4924 is nonexistent. However, there has been a suggestion thatPGC 63949 might be IC 4924, so it is discussed immediately below, essentially as a warning about that identification.

Apparent size 0.45 by 0.35 arcmin.

Historical Identification: Per Dreyer, IC 4925 (= Frost #1181, 1860 RA 19 50 24, NPD 143 14) is "faint, small, very much extended 170°". The position precesses to RA 20 01 11.9, Dec -52 51 21, only 0.7 arcmin northeast of the galaxy listed above and the description fits perfectly, so although there is a considerably brighter galaxy another arcmin to the south, the identification of PGC 63991 as IC 4925 is certain.
Physical Information: Apparent size 0.8 by 0.2 arcmin.

Historical Identification: Per Dreyer, IC 4926 (= Swift XI (#186), Howe, 1860 RA 19 50 51, NPD 128 57.2) is "most extremely faint, small, a little extended, very difficult, western of 2" (the other beingIC 4931). Dreyer knew that Swift's positions were, particularly this late in his career, relatively crude so although he credits Swift with the discovery he used Howe's position (1900 RA 19 53 32, Dec -38 50.9) for the object; hence the credit for both observers. Howe's position precesses to J2000 RA 20 00 12.9, Dec -38 34 35, right on the galaxy listed above, so the identification is certain.
Physical Information: Apparent size 1.3 by 1.0 arcmin.

Historical Identification: Per Dreyer, IC 4927 (= Frost #1182, 1860 RA 19 50 52, NPD 144 18) is "faint, small, extended 170°". The position precesses to RA 20 01 48.3, Dec -53 55 16, barely off the western rim of the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 1.1 by 0.3 arcmin.

Historical Identification: Per Dreyer, IC 4928 (= DeLisle Stewart #635, 1860 RA 19 50 53, NPD 167 41) is "extremely faint, very small, extremely extended 25°, extremely faint star 1 arcmin to north; suspected". The position precesses to RA 20 10 12.5, Dec -77 17 30, just an arcmin north of the galaxy listed above, the description fits perfectly and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 0.75 by 0.2 arcmin.

Historical Identification: Per Dreyer, IC 4929 (= DeLisle Stewart #633, 1860 RA 19 51 08, NPD 162 04) is "faint, small, considerably extended 15°". The position precesses to RA 20 06 34.7, Dec -71 40 49, only half an arcmin west of the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 1.3 by 0.3 arcmin.

Historical Identification: Per Dreyer, IC 4930 (= DeLisle Stewart #631, 1860 RA 19 51 27, NPD 144 41) is "considerably bright, small, much extended 45°, suspected". The position precesses to RA 20 02 26.1, Dec -54 18 09, (whence the position above), but there is nothing there nor anywhere near there. Per Corwin, this was on a one-hour Bruce plate, and if real would be very obvious; the fact that it is not means it was almost certainly a plate defect, and therefore a nonexistent object.

Historical Identification: Per Dreyer, IC 4931 (= Swift list XI (#187), Howe, 1860 RA 19 51 29, NPD 128 57.1) is "most extremely faint, pretty small, round, 8th magnitude star 20 seconds to east, eastern of 2" (the other beingIC 4926). As usual for objects discovered by Swift and reobserved by Howe, Dreyer used Howe's position (1900 RA 19 54 10, Dec -38 50.8), which precesses to RA 20 00 50.8, Dec -38 34 25, which falls right on the galaxy listed above. The description is perfect, and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 2.7 by 2.2 arcmin.

Historical Identification: Per Dreyer, IC 4932 (= Frost #1183, 1860 RA 19 51 30, NPD 143 13) has a "brighter middle, magnitude 15". The position precesses to RA 20 02 17.2, Dec -52 50 10, only 0.6 arcmin north northeast of the galaxy listed above and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 0.8 by 0.6 arcmin.

Historical Identification: Per Dreyer, IC 4933 (= DeLisle Stewart #632, 1860 RA 19 52 19, NPD 145 21) is "extremely faint, extremely small, 2 branch spiral". The position precesses to RA 20 03 23.3, Dec -54 58 00, just off the northeastern rim of the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 1.45 by 1.3 arcmin.

Historical Identification: Per Dreyer, IC 4934 (= DeLisle Stewart #636, 1860 RA 19 52 44, NPD 159 51) is "very faint, very small, considerably extended 15°, a little brighter middle; suspected". The position precesses to RA 20 07 11.3, Dec -69 27 37, about 1.2 arcmin north northwest of the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 1.5 by 0.25 arcmin.

Historical Identification: Per Dreyer, IC 4935 (= DeLisle Stewart #634, 1860 RA 19 53 07, NPD 147 58) is "very faint, very small, much extended 5°, star 1 arcmin to southwest; suspected". The position precesses to RA 20 04 35.1, Dec -57 34 49, about an arcmin north of the nucleus of the galaxy listed above, the description fits reasonably well and the star on its southwestern end makes the identification certain. (Keep in mind that precession not only changes the position of objects, but also changes the direction to the Poles, so that angles and directions from a century or more in the past are slightly altered at all declinations, and more so at far northern or southern declinations.)
Physical Information: Apparent size 1.6 by 0.5 arcmin.

Historical Identification: Per Dreyer, IC 4936 (= DeLisle Stewart #637, 1860 RA 19 53 42, NPD 151 49) is "extremely faint, very small, extremely extended 20°, 2 faint stars to northwest". The position precesses to RA 20 05 52.4, Dec -61 25 39, dead center on the galaxy listed above and the description fits perfectly, so the identification is certain.
Physical Information: Apparent size 1.75 by 0.7 arcmin.

Historical Identification: Per Dreyer, IC 4937 (= DeLisle Stewart #638, 1860 RA 19 54 04, NPD 146 38) is "extremely faint, very small, extremely extended 0°, nuclear; suspected". The position precesses to RA 20 05 18.7, Dec -56 14 40, just east of the northern arm of the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 2.35 by 0.4 arcmin.

Historical Identification: Per Dreyer, IC 4938 (= DeLisle Stewart #639, 1860 RA 19 54 16, NPD 150 35) is "a remarkable object, very faint, pretty small, annular, stellar nucleus, very faint star to southeast". The position precesses to RA 20 06 11.2, Dec -60 11 34, just off the northern rim of the galaxy listed above, the description fits perfectly and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 2.1 by 1.8 arcmin.

Historical Identification: Per Dreyer, IC 4939 (= DeLisle Stewart #640, 1860 RA 19 55 09, NPD 151 08) is "most extremely faint, extremely small, considerably extended 150°, faint star 2 arcmin to south". The position precesses to RA 20 07 10.0, Dec -60 44 24, within the western outline of the galaxy listed above, the description fits and the star to the south makes the identification certain.
Physical Information: Apparent size 1.2 by 0.65 arcmin.

Historical Identification: Per Dreyer, IC 4940 (= DeLisle Stewart #641, 1860 RA 19 55 52, NPD 135 06) is "faint, small, extended 100°". The position precesses to RA 20 05 43.5, Dec -44 42 28 (whence the position above), but there is nothing there nor anywhere near there that resembles the description. Per Corwin, this was identified on the same Bruce plate as the nonexistent IC 4922, and is almost certainly a plate defect; hence my decision to list it as nonexistent.

Historical Identification: Per Dreyer, IC 4941 (= Frost #1185, 1860 RA 19 55 59, NPD 144 03) is "faint, small, round, a little brighter middle, very diffuse". The position precesses to RA 20 06 50.3, Dec -53 39 22, about 1.2 arcmin west of the galaxy listed above, which fits the description, and there is nothing else nearby so the identification is certain.
Physical Information: Apparent size 0.95 by 0.75 arcmin.

Historical Identification: Per Dreyer, IC 4942 (= Frost #1184, 1860 RA 19 56 01, NPD 143 01) is "faint, very small, round". The position precesses to RA 20 06 44.2, Dec -52 37 22, about 1.1 arcmin southwest of the galaxy listed above and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 0.6 by 0.3 arcmin.

Historical Identification: Per Dreyer, IC 4943 (= Swift list XI (#188), 1860 RA 19 56 04, NPD 138 48.9) is "most extremely faint, pretty small, round, faint star to north, very difficult" (Swift's paper listed this as the western of two, the other beingIC 4949 =NGC 6861). The position precesses to RA 20 06 17.7, Dec -48 25 18, over 3 arcmin southwest of the galaxy listed above, but there is nothing else nearby, the star to its north makes the identification seem reasonable, and (per Corwin) the error in its position is similar to that for IC 4949, the "eastern of two" observed by Swift on the same night, making the identification reasonably certain.
Physical Information: Apparent size 1.0 by 1.0 arcmin.

Historical Identification: Per Dreyer, IC 4944 (= Frost #1186, 1860 RA 19 56 09, NPD 144 51) has a "brighter middle, magnitude 14". The position precesses to RA 20 07 06.8, Dec -54 27 19, just off the southwestern end of the galaxy listed above and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 1.5 by 0.6 arcmin.

Historical Identification: Per Dreyer, IC 4945 (= DeLisle Stewart #643, 1860 RA 19 56 10, NPD 161 25) is "faint, small, extended 5°, considerably brighter middle". The position precesses to RA 20 11 12.3, Dec -71 00 58, only 0.4 arcmin west of the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain. (IC 4945 is sometimes called NGC 6876A due to its general proximity toNGC 6876; but all that does is confuse the situation, since that designation is often assigned to the namesake galaxy, so it is far preferable to use its IC designation.)
Physical Information: About 1.1 by 0.4 arcmin.

Historical Identification: Per Dreyer, IC 4946 (= Swift list XII (#15), 1860 RA 19 56 12, NPD 134 25.9) is "extremely faint, small, round". The position precesses to RA 20 05 59.6, Dec -44 02 19, but there is nothing there or anywhere near there. However, (per Corwin) it appears that Swift simply made an error of 18 minutes of time in his right ascension (see theDiscovery Notes for more about that). Changing his position from (1900) RA 19 59 00, Dec -44 19.3 to (1900) RA 20 17 00, Dec -44 19.3 yields a precessed position of J2000 RA 20 23 53.6, Dec -44 00 05, which falls on the western end of the galaxy listed above, and the description in Swift's paper ("extremely faint, small, round, 3 or 4 stars to the east forming with the nebula a circle; southwestern of two") perfectly fits PGC 64614 providing that the "northeastern of two" (IC 4948) isNGC 6902 (as discussed in the entry for that object). So although the positional error is very large the identification seems reasonably certain and has apparently been generally accepted.
Discovery Notes: For the discussion above to be correct Swift must have made an error of 18 minutes of time in the right ascension for IC 4946and IC 4948. If the pair had been observed on the same night we could ascribe that to a careless error in setting the right ascension circle on his telescope; but according to Swift's paper they were observed six nights apart, so the error in right ascension is harder to explain. Per Corwin, one possibility is that the two were not observed six nights apart but on the same night, and Swift made an error in recording one of the dates. Another possibility is that on the second night Swift used the erroneous position of the first galaxy to set the right ascension circle, leading to an identical error in the position of the second galaxy. Whatever the cause of the mistake, the detailed description of the field near IC 4946 makes it almost certain that the two objects have been correctly identified, and although it would be nice to know why their positions were so far off, it is not necessary to actually know the reason.
Physical Information: Apparent size 2.5 by 1.1 arcmin.

Historical Identification: Per Dreyer, IC 4947 (= Frost #1187, 1860 RA 19 56 36, NPD 143 33) has a "brighter middle, magnitude 15". The position precesses to RA 20 07 23.0, Dec -53 09 16, about 1.5 southwest of the galaxy listed above, but there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 0.9 by 0.85 arcmin.

Historical Identification: Per Dreyer, IC 4948 (= Swift list XII (#16), DeLisle Stewart, 1860 RA 19 56 42, NPD 134 01) is "very faint, pretty small, round, 2 stars to east, star to northwest". The position precesses to RA 20 06 27.4, Dec -43 36 55, but there is nothing there or anywhere near there, due to errors made by both Swift and Stewart (whose position is the one Dreyer actually used, since he knew that Swift's later observations had relatively poor positions). Per Corwin, as in the case of his XII-#15 (=IC 4946), Swift made an 18 minute error in the right ascension of his XII-#16 (see theDiscovery Notes for IC 4946 for a discussion of possible reasons for the error). Correcting for the error by adding 18 minutes to Swift's position of (1900) RA 19 59 30, Dec -43 59.3 changes it to (1900) RA 20 17 30, Dec -43 59.3, which precesses to J2000 RA 20 24 22.2, Dec -43 40 01. That lies on the southwestern rim of the galaxy listed above, and as a result it is generally (though not universally) accepted as the correct identification for IC 4948. However, the galaxy was already listed as NGC 6902, so that designation is preferred, and even if IC 4948 is the same object it is merely a duplicate listing. (Given the large error in the right ascension, there was no way that Dreyer could have realized that IC 4948 might be the same as NGC 6902, so if they are the same, the duplicate listing was inevitable.)
Discovery Notes: Now what should we make of Stewart's position for Swift XII-#16? His position lies 5.3 arcmin south of Swift's original position, but at exactly the same (wrong) right ascension. Even if he simply copied Swift's right ascension without thinking, that would make his observation an even poorer one than Swift's; so it seems most likely that he actually "observed" something at his recorded position on the Bruce plate. But since there isn't anything there in the sky, if there was something on his plate it must have been a plate defect. As a result, his supposed reobservation of Swift's object was probably a "false positive". However, that hasn't prevented efforts to find something in the vicinity of Stewart's position that might correspond to IC 4948; in fact, thanks to an error in the ESO-Uppsala Survey, LEDA assigns that entry toPGC 64134, for which reason that galaxy, though certainlynot an IC object, is discussed in the next entry.
Physical Information: Given the duplicate entry, seeNGC 6902 for anything else.

Historical Misidentification: As discussed in the entry for IC 4948, the position for that object was well off the mark, and whatStewart "observed" at his position is unknown (most likely a plate defect, but an examination of the plate would be required to be sure). However, PGC 64134 was misidentified as IC 4948 in the ESO-Uppsala Survey, and is still misidentified in LEDA and as a result, Wikisky; so the main purpose of this entry is to serve as a warning about the misidentification. (We can be quite certain that it is a misidentification, as the object is far too small and too faint to have been seen by Stewart as anything but a faint star. It is also over 9 arcmin east of Stewart's position, but we could forgive that if it fit the description of the IC object.)
Physical Information: Apparent size 0.3 by 0.25 arcmin; nothing else known.

Historical Identification: Per Dreyer, IC 4949 (= Swift list XI (#189), 1860 RA 19 57 04, NPD 138 42.4) is "bright, very small, considerably extended" (Swift's paper added "eastern of two", the other beingIC 4943). The position precesses to RA 20 07 16.5, Dec -48 18 38, about 3.5 arcmin north of the galaxy listed above, but the description fits and there is nothing else nearby, so the identification would be considered reasonably certain even if there was nothing else to go on. However, Swift's remark about this being the "eastern of two" makes the identification absolutely certain, as the relative position of the two galaxies involved closely matches the relative positions in Swift's paper (though per Corwin, the correct identification appears to have been first pointed out by de Vaucouleurs, so quite some time passed between the publication of the IC2 and any modern confirmation of its identity). The double listing is due to the substantial error in Swift's declination, which led Dreyer to believe that Swift had found something separate from Dunlop's object, for whichJohn Herschel listed an accurate position.
Physical Information: Given the duplicate entry, seeNGC 6861 for anything else.