Historical Identification: Per Dreyer, IC 4650 (= Bigourdan #430, 1860 RA 17 13 28, NPD 32 31) is "extremely faint, stars and nebula". The position precesses to RA 17 15 51.4, Dec +57 19 49, an arcmin north of the star listed above, and 1.8 arcmin north northeast of the galaxy listed above. (Thomson suggests using the more accurate position from Bigourdan's "big list", instead of the rounded-off value in his Comptes Rendus paper. That yields a modern position of RA 17 15 51.7, Dec +57 19 14, only a third of an arcmin north of the star, and one and a quarter arcmin northeast of the galaxy.) Some references agree with Thomson's conclusion that the star is the correct IC 4650, while Corwin and others equate it with the galaxy, still others ignore the IC entry entirely, and in one case it is equated with NGC 6346, which is certainly wrong. This entry has been reserved for the historical discussion, and the probability that the star listed above is IC 4650. For a discussion of PGC 2562439, see the entry immediately below.

 Above, a 12 arcmin wide SDSS image centered on Bigourdan's position for IC 4650 (shown by a box). The star below the box is the one listed above as the probable IC 4650, while PGC 2562439 is the galaxy most often assumed to be IC 4650. Also shown are NGC 6338, which was the "comparison" object used by Bigourdan for his offsets, NGC 6345 and 6346, and IC 1252.

Historical Identification: See IC 4650 for a discussion of the possibility that this galaxy is the IC entry.
Physical Information: Based on a recessional velocity of 8005 km/sec, a straightforward calculation indicates that PGC 2562439 is about 375 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 360 million light years away at the time the light by which we see it was emitted, about 370 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 0.6 by 0.25 arcmin, the galaxy is about 65 thousand light years across.

Historical Identification: Per Dreyer, IC 4651 (= Bailey, 1860 RA 17 13 49, NPD 139 47) is a "cluster, pretty compressed". The position precesses to RA 17 24 37.6, Dc -49 55 17, about 2.7 arcmin northwest of the central condensation, but still within the overall outline of the cluster, so the identification is certain. Note: Dreyer did not credit Dunlop with this discovery (and if he had, would have done so in the original NGC given the early date of his observation) because Dunlop's observations were in many cases too poorly done for his successors to identify what he observed, and Dreyer had no idea that any of Dunlop's observations were connected to this object. However, Dunlop #402's position of 1827 RA 17 11 09, SPD 40 11 (= Dec -49 49) precesses to RA 17 24 30.6, Dec -49 59 35, about 4.5 arcmin southwest of the central condensation, but still within the cluster's boundary, and his description ("A very fine round cluster of very small stars, slightly compressed to the centre, about 8 arcmin in diameter") fits the cluster well, so it seems reasonably certain that Dunlop did observe the cluster, hence Steinicke's listing Dunlop as the actual discoverer.
Physical Information: Per Corwin, IC 4651 contains 50 to 75 stars of magnitude 10 and fainter scattered across a region 9 to 10 arcmin wide (the central condensation is only about 2 arcmin across). Studies of its Hertzsprung-Russell Diagram indicate that it is a little over a billion years old, and has a little over 600 solar masses contained in its "active" stars (that is, stars that have not yet died). About five times that mass is thought to be contained in white dwarfs and other dead stars, and nearly twice that total has probably been lost due to gravitational interactions with stars passing through it during its lifetime. Its distance is estimated at a little less than 3000 light years, in which case the entire cluster spans about 8 or 9 light years, and its central condensation a little less than 2 light years.

Historical Identification: Per Dreyer, IC 4652 (= Frost #1150, 1860 RA 17 14 10, NPD 149 35) is "faint, planetary, 15th magnitude". The position precesses to RA 17 26 35.1, Dec -59 43 03, just over an arcmin northeast of the galaxy listed above, and there is nothing else nearby, so the identification seems certain.
Physical Information: Apparent size 1.1 by 0.45 arcmin.

Historical Identification: Per Dreyer, IC 4653 (= DeLisle Stewart #442, 1860 RA 17 14 11, NPD 150 46) is "most extremely faint, extremely small, brighter middle, extremely faint star very near, suspected". The position precesses to RA 17 26 51.6, Dec -60 54 01, a little over 2 arcmin southwest of the galaxy listed above, the description fits and there is nothing else nearby, so the identification seems certain.
Physical Information: Based on a recessional velocity of 1920 km/sec (and H₀ = 70 km/sec/Mpc), IC 4653 is about 90 million light years away (the HST press release uses 80 million light years for the distance). Given that, its apparent size of about 0.9 by 0.5 arcmin for the brighter inner region spans about 20 to 25 thousand light years, and the apparent size of about 1.2 by 0.75 arcmin for the fainter halo (both sizes from the images below), corresponds to about 30 thousand light years. The galaxy has obviously been severely disturbed in relatively recent times, probably either by a galaxy that has long since passed out of the field of view, or perhaps by a smaller companion that ended up merging with the galaxy we now see (the ringlike outer structure would be a natural result of a "minor" collision with the original core of the galaxy).

Historical Identification: Per Dreyer, IC 4654 (= DeLisle Stewart #444, 1860 RA 17 19 08, NPD 164 16) is "extremely faint, extremely small, round, very much brighter middle". The position precesses to RA 17 37 18.5, Dec -74 22 28, on the eastern rim of the galaxy listed above, so the identification is certain.
Physical Information: Apparent size 1.85 by 1.05 arcmin.

Historical Identification: Per Dreyer, IC 4655 (= DeLisle Stewart #445, 1860 RA 17 21 54, NPD 150 37) is "extremely faint, extremely small, much extended 170°". The position precesses to RA 17 34 34.1, Dec -60 43 28, only 0.2 arcmin west of a nearly north-south line of half a dozen stars that perfectly matches the description, so the identification seems certain.
Physical Information: Apparent length of the line of stars is 0.7 arcmin.

Historical Identification: Per Dreyer, IC 4656 (= DeLisle Stewart #446, 1860 RA 17 24 16, NPD 153 38) is "most extremely faint, very small, extremely extended 90°, considerably brighter middle". The position precesses to RA 17 37 41.6, Dec -63 43 55, right on the galaxy listed above, and the description fits perfectly, so the identification is certain.
Physical Information: Apparent size 2.5 by 0.65 arcmin.

Historical Identification: Per Dreyer, IC 4657 (= Barnard, 1860 RA 17 24 34, NPD 107 25.1) is "very faint, 11th magnitude star 2 arcmin northwest". The position precesses to RA 17 32 42.6, Dec -17 31 29 (whence the position above), but there is nothing there. The field is completely stellar, and although there are numerous asterisms that might or might not be what Barnard observed, in addition to a number of stars that might be the one referred to, it does not appear that there is anything of interest located 2 arcmin to the southeast of any particular star. So at least for now, the object must be listed as lost or nonexistent.

Historical Identification: Per Dreyer, IC 4658 (= Frost #1151, 1860 RA 17 24 45, NPD 149 29) is "faint, planetary, 15th magnitude" (the 1860 RA is off by a minute, due to a transcription error by Dreyer in precessing from the correct 1900 coordinates; as a result, the 1860 RA should read 17 23 45). The (corrected) position precesses to RA 17 36 10.7, Dec -59 35 07 (whence the position above), but there is nothing there nor anywhere near there that is a suitable candidate for IC 4658. There is a very faint galaxy (PGC 60555) 2.5 arcmin north of the position that until recently was generally identified as IC 4658, though usually with some indication of doubt. The doubt was based on the fact that the description for IC 4658 is identical to that for IC 4652, found by Frost on the same plate, and that galaxy is far larger and brighter than PGC 60555. Since the fainter galaxy does not match the description, it is almost certainly not IC 4658, and what Frost actually observed is probably unknown or a plate flaw. However, Corwin has proposed that PGC 60594 is a suitable candidate, and although there are some problems with his suggestion, the possibility of its being correct is discussed in the second entry below.

Historical Identification: See IC 4658 for a discussion of why PGC 60555 cannot be that IC object.
Physical Information: Apparent size 0.5 by 0.2 arcmin; nothing else available.

Historical Identification: As noted in the discussion of IC 4658, if that object is real it must be similar in brightness to IC 4652, which has an identical description, and was found on the same plate. Per Corwin, the closest object of similar aspect is the galaxy listed above; but it is 1.5 minutes of time to the east and 20 arcmin to the south of Frost's position for IC 4658, which is a very uncharacteristic error for Frost, especially since the two other galaxies he found on the plate in question are very close to their recorded positions. However, Corwin notes that the positional errors are close to whole- or half-digit errors, which are the most common kind of transcription and reduction errors, and since the position of IC 4658 was closer to the edge of the plate than the other galaxies, field distortion might have been large enough to partially account for the error. Fortunately, almost all of the Bruce plates still exist, and if an opportunity arises to examine the plate, it might be proven that PGC 60594 is indeed IC 4658; but without such an examination, it seems more likely that it was a plate flaw, so for now Corwin's suggestion must remain only that, and not an actual identification.
Physical Information: Based on a recessional velocity of 5100 km/sec, PGC 60594 is about 235 million light years away. Given that and its apparent size of 2.4 by 1.7 arcmin, it is about 165 thousand light years across. Because of its exceptionally bright core, it is listed as a Seyfert galaxy (type Sy 2).

Historical Identification: Per Dreyer, IC 4659 (= Barnard, 1860 RA 17 26 02, NPD 107 49.6) is "pretty faint, small, 8th magnitude star 21 seconds of time to east, 3 arcmin to north". The position precesses to RA 17 34 12.1, Dec -17 55 41 (whence the position above), but there is nothing in the field that corresponds to the description. The nearest 8th magnitude star is 5 1/2 arcmin to the north and 13 seconds of time to the west, and the field is completely stellar, so if Barnard saw anything real it must have been some kind of asterism which would be next to impossible to identify even if the star's relative position were correct; hence the description of IC 4659 as either lost or nonexistent.

Historical Identification: Per Dreyer, IC 4660 (= Roberts, 1860 RA 17 26 40, NPD 14 01.0) is "pretty large, extended north-south, 9.2 magnitude star 30 arcsec southwest". The position precesses to RA 17 21 33.3, Dec +75 51 42, only an arcmin northwest of the galaxy listed above, which perfectly fits the description, and the star to its southwest makes the identification certain.
Physical Information: Apparent size 1.5 by 0.35 arcmin.

Historical Identification: Per Dreyer, IC 4661 (= DeLisle Stewart #447, 1860 RA 17 32 58, NPD 163 58) is "extremely faint, very small, round, considerably brighter middle". The position precesses to RA 17 50 58.7, Dec -74 01 41, right on the galaxy listed above, so the identification is certain.
Physical Information: Apparent size 1.85 by 1.6 arcmin.

Historical Identification: Per Dreyer, IC 4662 (= Innes (#14), DeLisle Stewart, 1860 RA 17 33 20, NPD 154 36.5) is "faint, pretty small, a little extended". The position precesses to RA 17 47 03.6, Dec -64 40 32, about 1.5 arcmin south southwest of the galaxy listed above, and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 3.5 by 2.1 arcmin.

Physical Information: Apparent size 1.3 by 0.9 arcmin.

Historical Identification: Per Dreyer, IC 4664 (= Fleming #97, 1860 RA 17 35 10, NPD 134 51) is a "planetary, stellar". The position precesses to RA 17 45 26.0, Dec -44 55 01, less than an arcmin southwest of the nebula listed above, and there is nothing similar nearby, so the identification is certain.
Physical Information: Apparent size 20 by 16 arcsec.

Historical Identification: Per Dreyer, IC 4664 (= DeLisle Stewart #448, 1860 RA 17 35 36, NPD 153 12) is "extremely faint, very small, considerably extended, considerably brighter middle". The position precesses to RA 17 48 56.1, Dec -63 15 37, right on the galaxy listed above, so the identification is certain.
Physical Information: Apparent size 1.55 by 1.1 arcmin.

Historical Identification: Per Dreyer, IC 4665 (= Bailey, 1860 RA 17 39 26, NPD 84 14) is a "cluster, coarse". The position precesses to RA 17 46 17.6, Dec +05 42 30, well within the scattered grouping of bright stars that makes up this cluster, so the identification is certain.
Discovery Notes: Although the discovery of IC 4665 was attributed to Solon Bailey by Dreyer, this cluster was recorded by several other observers, dating back at least to de Chéseaux, hence his listing above as the actual discoverer. As noted in his biography, de Chéseaux's short list was more or less ignored for the best part of 150 years, so none of his discoveries were attributed to him by Dreyer. The object was also recorded by Bode as one of 110 non-stellar objects scattered through his 1782 catalog of the sky, but as just a needle in the haystack of stars in Bode's list, it didn't attract any attention. It was also observed (either on July 15, 1781 and/or Jul 31, 1783, depending on the reference) by William Herschel and his sister Caroline (on July 31, 1783), but was not included in Herschel's published catalogs, so it did not make it into the GC or the NGC/IC. As a result, Bailey's publication of a list of about 300 clusters and nebulae in 1908 was the first time Dreyer became aware of its existence.
Physical Information: Apparent size 40 arcmin for central condensation? 70 arcmin for possible outliers?

Historical Identification: Per Dreyer, IC 4666 (= Bigourdan #431, 1860 RA 17 43 28, NPD 34 10) is an "extremely faint star, slightly nebulous". The position precesses to RA 17 46 03.6, Dec +55 46 54, less than 0.4 arcmin north northeast of the star listed above, and given Bigourdan's tendency to see ordinary stars as slightly nebulous objects, no one has expressed any doubts about the identification of this star as the IC object. However, Bigourdan's position was only an estimate, so though this star is the most likely candidate, what he actually observed cannot be stated with absolute certainly.

Historical Identification: Per Dreyer, IC 4667 (= Bigourdan #432, 1860 RA 17 43 45, NPD 34 04) is "2 suspected stellar nebulae". The position precesses to RA 17 46 19.5, Dec +55 52 57 (whence the position above), but there is nothing obvious there. However, as in the case of IC 4666, Bigourdan's discussion expresses considerable uncertainty about what he was referring to, and his positions are at best only estimates. As a result there is no lack of faint objects that might be what he observed; for instance, the star and faint galaxy 80 arcsec south of his position fit the description, and is the closest pair to the published position. But proving that this or any other pair of objects is what Bigourdan was referring to is probably impossible, so although his "2 suspected stellar nebulae" probably exist, they are almost certainly lost.

Historical Identification: Per Dreyer, IC 4668 (= Bigourdan #433, 1860 RA 17 44 39, NPD 32 33) is "extremely faint, star 3 arcmin north". The position precesses to RA 17 46 57.0, Dec +57 24 06, only a third of an arcmin west of the star listed above, and the 9th magnitude star 4 arcmin north northwest appears to make the identification certain. Unfortunately, things are not that simple, as the position Bigourdan gives for his comparison star is wrong. He states that it is at B1900 RA 17 45 48, Dec +57 19, and is a 10th magnitude star 36 seconds of time to the east and 10 arcmin to the south of BD+57 1803 (which is HD 162279). Using the modern position of the BD star (and correcting for its proper motion since Bigourdan's observation), precessing to Bigourdan's equinox and applying the offsets for his comparison star places it near J2000 RA 17 47 29, Dec +57 18. The 10th magnitude star nearest that position lies 3 arcmin south, at RA 17 47 27.6, Dec +57 15 09, or B1900 RA 17 45 47.7, Dec +57 17 06, which is two arcmin south of the position used by Bigourdan. As a result, his #433 should fall in an empty region about 2 arcmin south of the star listed above, which would make IC 4668 "lost or nonexistent". Corwin attempts to save the situation by supposing that the coordinates used by Bigourdan for his comparison star refer not to the 10th magnitude star, but to a 13th magnitude star two arcmin to its north that has almost exactly the position given by Bigourdan. Converting that star's current position of J2000 RA 17 47 30.2, Dec +57 16 50 to Bigourdan's equinox and applying his offsets of 29.18 seconds of time west and 7 arcmin 6.3 arcsec north of the comparison star to find his #433, we obtain a position of B1900 RA 17 43 39.3, Dec +57 28 17 (= J2000 RA 17 45 17.8, Dec +57 26 01), which lies only 10 arcsec south of the star listed above. This seems like a lot of work to get right back to where we started off, and normally I would not discuss things in this sort of detail, but it is a good illustration of the effort required to confirm that what is obvious is correct, and the problems faced by those making that effort to solve difficult cases. But going through all of this raises the question, would Bigourdan have used a 13th magnitude star for his comparison star when there was a 10th magnitude star not far from it? It seems more likely that he would have used the brighter star (as he claimed he did), in which case IC 4668 would be lost or nonexistent; but if he did use the brighter star, wouldn't he have measured its offset from the BD star at 12 to 14 arcmin, instead of 10? So it does seem possible that he used the fainter star for a comparison star, in which case the star listed above would be IC 4668 after all. No one can answer such questions without any doubt, but on the whole it feels more likely to me that Corwin is correct than not, hence my description of the object as "probably a star", instead of "perhaps a star".

Historical Identification: Per Dreyer, IC 4669 (= Bigourdan #328, 1860 RA 17 45 46, NPD 28 30) is "extremely faint, small, perhaps extremely faint star involved". The position precesses to RA 17 47 12.7, Dec +61 27 15, about 1.2 arcmin north of the galaxy listed above, which fits the description, and there is nothing else nearby, so the identification seems certain.
Physical Information: Apparent size of central galaxy about 0.65 by 0.35 arcmin; of the galaxy and its extended arms, about 1.0 by 0.9 arcmin.

Historical Identification: Per Dreyer, IC 4670 (= Lunt (#7), 1860 RA 17 46 43, NPD 111 46.3) is "stellar, 12.5 magnitude". The position precesses to RA 17 55 08.0, Dec -21 48 09, exactly 3.5 arcmin due south of the position of the nebula listed above, in a completely stellar field that gives no hint of what Lunt might have observed. Fortunately, the original paper adds that the object was found with a 24 inch objective prism (meaning that even though it isn't mentioned in the description, the object was known to be a planetary nebula due to its unusual spectrum), and notes that it was southeast of CPD-21 6502, and 2.5 seconds of time due west of a star of similar brightness. CPD-21 6502 is an 11th magnitude star at RA 17 55 00.5, Dec -21 43 26, and just under 2 arcmin southeast of that star there is a planetary nebula (namely, the one listed above) that lies 2.5 seconds of time due west of a suitable star, so despite the poor position, the identification is certain.
Physical Information: Apparent size (from closeup image) about 8 arcsec; generally listed about 7 arcsec, but images below are undoubtedly overexposed.

Historical Identification: Per Dreyer, IC 4671 (= DeLisle Stewart #449, 1860 RA 17 47 24, NPD 100 15) is "Spiral? (edge of plate)". The position precesses to RA 17 55 08.2, Dec -10 16 47 (whence the position above), but there is nothing there, save for an almost completely stellar field. Corwin suspects this is a plate defect, but notes that the plate should be checked to be sure. In any event, the object is either lost or nonexistent.

Historical Identification: Per Dreyer, IC 4672 (= DeLisle Stewart #450, 1860 RA 17 49 07, NPD 152 49) is "most extremely faint, extremely small, very extended 45°, considerably brighter middle". The position precesses to RA 18 02 21.7, Dec -62 49 52, only 0.8 arcmin east of the galaxy listed above, it fits the description, and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 0.85 by 0.45 arcmin.

Historical Identification: Per Dreyer, IC 4673 (= Barnard ((A. N.) 3315), 1860 RA 17 54 34, NPD 117 06.9) is "planetary, 13th magnitude, 13th magnitude star 33 arcsec northeast". The position precesses to RA 18 03 20.1, Dec -27 07 07, only 0.8 arcmin southeast of the planetary nebula listed above, and the star to the northeast of the nebula makes the identification certain.
Physical Information: Apparent size 25 by 17 arcsec.

Historical Identification: Per Dreyer, IC 4674 (= DeLisle Stewart #451, 1860 RA 17 55 03, NPD 152 25) is "extremely faint, very small, extremely extended 80°, considerably brighter middle, stellar nucleus". The position precesses to RA 18 08 11.4, Dec -62 24 40, just under an arcmin south of the galaxy listed above, the description fits perfectly, and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 1.6 by 0.65 arcmin.

Historical Identification: Per Dreyer, IC 4675 (= Bigourdan #329, 1860 RA 17 55 31, NPD 99 15) is "doubtful, not seen a second time". The position precesses to RA 18 03 11.8, Dec -09 15 08 (whence the position above), but there is nothing there. However, given the description, that is hardly surprising. In fact, per Corwin, Bigourdan only thought he might have seen something on the night he recorded the object, shortly before it became too cloudy to continue; and when he checked the region on another night, he found nothing at all at his position. So the object is obviously nonexistent, and the only question is why Bigourdan even bothered to list it as a "nova".

Historical Identification: Per Dreyer, IC 4676 (= Barnard, 1860 RA 17 56 17, NPD 78 10.9) is "extremely faint, very small". The position precesses to RA 18 02 48.2, Dec +11 49 00, about 1.2 arcmin west of the galaxy listed above, but the description is appropriate and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 0.6 by 0.35 arcmin.

Historical Identification: Per Dreyer, IC 4677 (= Barnard, 1860 RA 17 58 19, NPD 23 21.6) is "very faint, small, IV.37 is 16.5 seconds of time to east" (WH IV.37 being NGC 6543, the Cat's Eye Nebula). The position precesses to RA 17 58 16.2, Dec +66 38 03, right on the object listed above, and the description fits perfectly, so the identification is certain. However, IC 4677 is not a separate entity, but merely a bright knot in the outermost part of NGC 6543. Since the outer portion of the planetary nebula is much fainter than the bright central regions, there was a long period when it wasn't realized how large NGC 6543 is, and IC 4677 was thought to be a separate object; as ironically noted by Corwin, the IC object was even misidentified as an interacting galaxy by Vorontsov-Velyaminov, one of the early experts on planetary nebulae.
Physical Information: Apparent size 1.1 by 0.6 arcmin. Part of planetary nebula NGC 6543, which see for anything else.

Historical Identification: Per Dreyer, IC 4678 (= Barnard ((A. N.) 4239), 1860 RA 17 59 25, NPD 113 53) is "bright, small, extended" (As in the case of IC 4681 and 4684, Barnard's positions were rough, and included ± signs to indicate that, but Dreyer chose to leave them out, creating an impression of accuracy that didn't necessarily exist). The position precesses to RA 18 07 58.1, Dec -23 52 15, but there is nothing obvious anywhere near his position. However, per Corwin, there is a nebulous region 1.5 minutes of time to the west (and 5 arcmin to the south) that would stand out on the blue-sensitive plate used by Barnard, and is almost certainly what he observed. The error in position seems large, but as noted above the position was stated as rough by Barnard, and other nebulae that he observed in this region have similar or even larger errors.
Physical Information: Apparent size 7.5 by 2.5 arcmin.

Historical Identification: Per Dreyer, IC 4679 (= DeLisle Stewart #452, 1860 RA 17 59 31, NPD 146 17) is "considerably faint, small, round, very much brighter middle; suspected". The position precesses to RA 18 11 21.5, Dec -56 15 53, less than an arcmin southwest of the galaxy listed above, and there is nothing else nearby, so the identification seems certain.
Physical Information: Apparent size 2.2 by 1.1 arcmin.

Historical Identification: Per Dreyer, IC 4680 (= DeLisle Stewart #453, 1860 RA 17 59 41, NPD 154 30) is "extremely faint, very small, extremely extended 85°, considerably brighter middle". The position precesses to RA 18 13 23.2, Dec -64 28 40, within the western outline of the galaxy listed above, and the description fits, so the identification is certain.
Physical Information: Apparent size 2.0 by 0.8 arcmin.

Historical Identification: Per Dreyer, IC 4681 (= Barnard ((A. N.) 4239), 1860 RA 17 59 46, NPD 113 25) is a "small nebula or nebulous star" (As in the case of IC 4678 and 4684, Barnard's positions were rough, and included ± signs to indicate that, but Dreyer chose to leave them out, creating an impression of accuracy that didn't necessarily exist). The position precesses to RA 18 08 17.3, Dec -23 24 11 (whence the position above), in a region so obscured by absorption nebulae that although the position falls almost exactly on a faint star, it can't possibly fit the description. Corwin suggests that HD 165705, the 10th magnitude star 1.8 arcmin southwest of Barnard's position, might have given the impression of being nebulous due to the stellar background surrounding it, and as a result it is often listed as IC 4681, but although if something must be assigned to the entry that star will do as well as anything else (and certainly better than other similar suggestions), it seems just as likely that IC 4681 is lost or nonexistent.

Historical Identification: Per Dreyer, IC 4682 (= DeLisle Stewart #454, 1860 RA 17 59 52, NPD 161 37) is "very faint, considerably small, considerably extended 140°, stellar nucleus". The position precesses to RA 18 16 24.5, Dec -71 35 20, on the southern half of the galaxy listed above, and the description fits, so the identity is certain.
Physical Information: Apparent size 2.7 by 1.8 arcmin.

Historical Identification: Per Dreyer, IC 4683 (= Wolf ((A. N.) 3848), 1860 RA 18 00, NPD 116 15) is "very faint, most extremely large". The position precesses to RA 18 08 42.5, Dec -26 14 07, which because of the rough nature of Barnard's observation is rounded off to the nearest minute of time and arc in describing IC 4683. Per Corwin, Barnard only indicated that the "nebula" was a region covering about 8 square degrees (that is, nearly 3 degrees on a side) to the southeast of M8, the Lagoon Nebula. Given the nature of the field, this is only a portion of the star clouds (regions with innumerable stars) that fill the sky in this portion of the Milky Way, and not any specific object.
Physical Information: Apparent size (per Barnard) nearly 3 degrees.

Historical Identification: Per Dreyer, IC 4684 (= Barnard ((A. N.) 4239), 1860 RA 18 00 35, NPD 113 26) is a "small nebula or nebulous star" (As in the case of IC 4678 and 4681, Barnard's positions were rough, and included ± signs to indicate that, but Dreyer chose to leave them out, creating an impression of accuracy that didn't necessarily exist; but in this case the position isn't that bad). The position precesses to RA 18 09 06.3, Dec -23 25 01, about 1.2 northwest of the brighter star in the nebula listed above, and given the description, the identification seems certain.
Physical Information: Apparent size 2.8 by 1.7 arcmin.

Historical Identification: Per Dreyer, IC 4685 (= Barnard ((A. N.) 4239), 1860 RA 18 00 44, NPD 114 00.3) is a "7.5 magnitude star in a large, diffuse nebula". The position precesses to RA 18 09 17.6, Dec -23 59 17, right on HD 165921, a magnitude 7.3 star that must be what Barnard observed, so the identification is certain (the position of the cluster listed above is the position of the star). The star is surrounded by a large diffuse nebula, but it is also considered to be at the center of a loose cluster of stars, hence the description of the IC object as an open cluster.
Physical Information: Apparent size 15 by 10 arcmin?

Historical Identification: Per Dreyer, IC 4686 (= Frost #1152, 1860 RA 18 01 32, NPD 147 46) is has a "brighter middle, magnitude 14". The position precesses to RA 18 13 38.7, Dec -57 44 27, between the middle and southern galaxies in a trio of galaxies (IC 4686, 4687 and 4689) discovered by Frost on the same plate. All are described in exactly the same way, so to tell which galaxy corresponds to which IC object all we have to do is compare Frost's relative positions. His #1152 lies in between his #1153 and #1154, so IC 4686 is the (middle) galaxy listed above, and its identification is certain.
Physical Information: The recessional velocity of IC 4686 is 4950 km/sec, but since it is obviously interacting with its neighbors, it seems best to use the average recessional velocity of the three galaxies to estimate their distance. That value is 5035 km/sec, which indicates a distance of about 235 million light years. Given that and the 0.55 by 0.55 arcmin apparent size of the galaxy's brighter central region (including the area estimated to be obscured by IC 4687), IC 4686 is about 35 thousand light years across. The fainter outer regions, filled with stars and gas torn from the galaxy, spans 0.8 by 0.8 arcmin, and is about 55 thousand light years across.

Historical Identification: Per Dreyer, IC 4687 (= Frost #1153, 1860 RA 18 01 32, NPD 147 45) has a "brighter middle, magnitude 14". The position precesses to RA 18 13 38.5, Dec -57 43 27, on the western rim of the galaxy listed above, which is the northernmost in a trio of galaxies (IC 4686, 4687 and 4689) discovered by Frost on the same plate. All are described in exactly the same way, so to be certain which galaxy corresponds to which IC object all we have to do is compare Frost's relative positions. His #1153 lies north of his #1152 and #1154, so IC 4687 is the (northernmost) galaxy listed above, and its identification is certain.
Physical Information: The recessional velocity of IC 4687 is 5200 km/sec, but since it is obviously interacting with its neighbors, it seems best to use the average recessional velocity of the three galaxies to estimate their distance. That value is 5035 km/sec, which indicates a distance of about 235 million light years. Given that and the apparent size of 1.0 by 0.6 arcmin for the main galaxy, IC 4687 is about 70 thousand light years across; including the extended northern streamers, the galaxy spans an area of 1.45 by 1.35 arcmin, which corresponds to about 100 thousand light years.

Historical Identification: Per Dreyer, IC 4688 (= Barnard, 1860 RA 18 01 34, NPD 78 18.8) is "very faint, pretty small, diffuse, 12th magnitude star close to east". The position precesses to RA 18 08 05.6, Dec +11 42 11, about 1.5 arcmin west of the galaxy listed above, but there is nothing else nearby, and the star southeast of the galaxy makes the identification certain.
Physical Information: Apparent size 1.4 by 1.15 arcmin.

Historical Identification: Per Dreyer, IC 4689 (= Frost #1154, 1860 RA 18 01 38, NPD 147 47) has a "brighter middle, magnitude 14". The position precesses to RA 18 13 44.9, Dec -57 45 26, slightly southeast of the galaxy listed above, which is the southernmost in a trio of galaxies (IC 4686, 4687 and 4689) discovered by Frost on the same plate. All are described in exactly the same way, so to be certain which galaxy corresponds to which IC object all we have to do is compare Frost's relative positions. His #1154 lies south of his #1152 and #1153, so IC 4689 is the (southernmost) galaxy listed above, and its identification is certain.
Physical Information: The recessional velocity of IC 4689 is 4950 km/sec, but since it is probably interacting with its neighbors, it seems best to use the average recessional velocity of the three galaxies to estimate their distance. That value is 5035 km/sec, which indicates a distance of about 235 million light years. Given that and its apparent size of 1.0 by 0.45 arcmin, IC 4687 is about 70 thousand light years across.

Historical Identification: Per Dreyer, IC 4690 (= Barnard ((A. N.) 4239), 1860 RA 18 02 10, NPD 109 50.5) is a "9.5 magnitude star in a nebula, extended southwest-northeast". The position precesses to RA 18 10 27.8, Dec -19 49 13, but there is nothing there save for some faint stars, including most notably (considering the following discussion) BD -19° 4881. Per Corwin, the problem is a misidentification by Barnard of the star he listed as BD -19° 4881. In A. N. 4239 Barnard states "The two stars BD -19° 4881 and -19° 4946 are closely and densely nebulous. The nebulosity about -19° 4881 is somewhat extended northeast and southwest. They seem to be connected with the larger nebulosity surrounding -19° 4953." The problem with this description is that BD -19° 4881 is over 6 minutes of time to the west of BD -19° 4946 and BD -19° 4953, which means it can't be "closely" connected with either, and must indeed have been misidentified. A look at the region near BD -19° 4946 and -19° 4953 (as shown in the illustration below) indicates that he must have observed BD -19° 4940, with a current position of RA 18 16 52.0, Dec -19 46 42 (whence the position above), and the identification given above is certain. (Rather ironically, Barnard is responsible for the correct identification of NGC 6589, as discussed at that entry; and if he hadn't misidentified BD -19° 4940, there wouldn't have been a duplicate entry for this object.)
Physical Information: Given the duplicate entry, see NGC 6589 for anything else.

 Above, a 24 arcmin wide DSS image showing the region near BD -19° 4940 (= IC 4690 = NGC 6589), BD -19° 4946 (= NGC 6590) and BD -19° 4953 (= IC 1284), "=" indicating that those stars are used to define the positions of the emission and reflection nebulae surrounding them.

Historical Identification: Per Dreyer, IC 4691 (= Barnard, 1860 RA 18 02 14, NPD 78 12) is "faint, small, irregular figure, 1 or 2 faint stars involved". The position precesses to RA 18 08 45.2, Dec +11 49 07, only 0.6 arcmin south 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 0.65 arcmin.

Historical Identification: Per Dreyer, IC 4692 (= DeLisle Stewart #455, 1860 RA 18 02 29, NPD 148 43) is "faint, small, irregular figure, suspected". The position precesses to RA 18 14 46.8, Dec -58 41 14, on the northwestern rim of the galaxy listed above, and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 1.9 by 0.9 arcmin.

Historical Identification: Per Dreyer, IC 4693 (= Bigourdan #330, 1860 RA 18 02 59, NPD 72 41) is "extremely faint, small, brighter middle, several extremely faint stars involved". The position precesses to RA 18 09 11.0, Dec +17 20 15, only half an arcmin south of the three stars listed above. Per Corwin, Bigourdan notes two neighboring stars whose position relative to the triplet make the identification certain; Bigourdan also states that the object was actually found by "M. Callandreau".

Historical Identification: Per Dreyer, IC 4694 (= DeLisle Stewart #456, 1860 RA 18 03 13, NPD 148 14) is "faint, small, extremely extended 20°, a little brighter middle". The position precesses to RA 18 15 25.0, Dec -58 12 06, on the northwestern border of the galaxy listed above, the description fits, and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 2.4 by 0.9 arcmin.

Historical Identification: Per Dreyer, IC 4695 (= DeLisle Stewart #457, 1860 RA 18 05 04, NPD 148 57) is "extremely faint, very small, round, brighter middle, several stars near; suspected". The position precesses to RA 18 17 24.5, Dec -58 54 42, about 0.8 arcmin north of the close double listed above. Per Corwin, this pair is consistent with Stewart's description, including the several stars surrounding it. (He adds that "suspected" means that Stewart observed the object on only one plate, and had no separate confirmation of its existence.) Given the fact that many "extremely faint" IC objects turn out to be stellar, the identification is considered reasonably certain. (There has also been a suggestion that IC 4695 should include some of the fainter stars closest to the double, in which case the double would presumably be the "brighter middle".)

Historical Identification: Per Dreyer, IC 4696 (= DeLisle Stewart #458, 1860 RA 18 06 28, NPD 154 48) is a "nebula, suspected". The position precesses to RA 18 20 14.8, Dec -64 45 17, about 1.3 arcmin south southwest of the galaxy listed above, and since there is nothing else nearby the identification is certain.
Physical Information: Apparent size 2.6 by 0.85 arcmin.

Historical Identification: Per Dreyer, IC 4697 (= Javelle #1402, 1860 RA 18 06 46, NPD 64 36.5) is "faint, small, irregular figure, mottled but not resolved". The position precesses to RA 18 12 27.5, Dec +25 25 28, on the eastern edge of the bright core of the galaxy listed above, and although there is another galaxy just to the northeast, it is so much fainter that if Javelle had seen it, he would have seen both galaxies. Since he saw only one and its position is dead on, the identification with the brighter galaxy is certain.
Physical Information: Apparent size of central galaxy about 0.95 by 0.3 arcmin; of distorted outer regions, about 1.3 by 1.0 arcmin.

Historical Identification: Per Dreyer, IC 4698 (= DeLisle Stewart #459, 1860 RA 18 07 40, NPD 153 25) is "extremely faint, very small, extremely extended 45°, stellar nucleus". The position precesses to RA 18 21 03.1, Dec -63 22 04, about 1.2 arcmin south southeast 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 4699 (= Fleming #98, 1860 RA 18 08 08, NPD 136 03) is a "planetary, stellar". The position precesses to RA 18 18 31.9, Dec -46 00 17, about 1.2 arcmin due south of the planetary nebula listed above, and there are no similar objects nearby, so the identification is certain.
Physical Information: Apparent size 16 by 13 arsec.