Celestial Atlas
(IC 4500 - 4549) ←     IC Objects: IC 4550 - 4599     → (IC 4600 - 4649)
Click here for Introductory Material
QuickLinks:
4550, 4551, 4552, 4553, 4554, 4555, 4556, 4557, 4558, 4559, 4560, 4561, 4562, 4563, 4564, 4565, 4566,
4567, 4568, 4569, 4570, 4571, 4572, 4573, 4574, 4575, 4576, 4577, 4578, 4579, 4580, 4581, 4582, 4583,
4584, 4585, 4586, 4587, 4588, 4589, 4590, 4591, 4592, 4593, 4594, 4595, 4596, 4597, 4598, 4599

Page last updated Feb 21, 2014
WORKING 4560: Waiting for clarification from Corwin
WORKING: Add physical data

IC 4550 (=
NGC 5946 = GCL 36)
Discovered (May 8, 1826) by James Dunlop (and later listed as NGC 5946)
Discovered (May 24, 1898) by Lewis Swift (and later listed as IC 4550)
A magnitude 8.4 globular cluster (type IX) in Norma (RA 15 35 28.5, Dec -50 39 32)
Historical Identification: Per Dreyer, IC 4550 (= Swift list XI (#180), 1860 RA 15 24 37, NPD 140 10.6) is "bright, pretty small, a little extended". The position precesses to RA 15 34 46.6, Dec -50 39 08, but there is nothing there save for NGC 5946, which lies just over 10 arcmin due east. Per Corwin, there is no doubt that the globular cluster is what Swift observed, as there is nothing else that matches Swift's description in the area, and in some ways it is surprising that he observed it at all, as it is one of the fainter Milky Way globular clusters, and would have been no more than 5 or 6 degrees above the southern horizon at Swift's location. Given the error in Swift's position, Dreyer's duplicate entry was inevitable.
Physical Information: Given the duplicate entry, see NGC 5946 for anything else.
DSS image of region near the IC2 position for IC 4550, also showing NGC 5946
Above, a 15 arcmin wide DSS image centered on the IC2 position for IC 4550, also showing NGC 5946

IC 4551 (probably =
NGC 5964 = PGC 55637)
Discovered (Apr 24, 1830) by John Herschel (and later listed as NGC 5964)
Discovered (Aug 19, 1897) by Lewis Swift (and later listed as IC 4551)
A magnitude 11.9 spiral galaxy (type SB(rs)d?) in Serpens (RA 15 37 36.2, Dec +05 58 25)
Historical Identification: Per Dreyer, IC 4551 (= Swift list XII (#12), 1860 RA 15 27, NPD 83 30.8) is "most extremely faint, large, round, very diffuse". The position precesses to RA 15 33 54.0, Dec +06 00 48, but there is nothing there. Per Corwin, Swift listed the right ascension with a question mark, suggesting that what he observed should be close to an east-west line near the IC2 position. There is a suitable object (NGC 5964) about 3.5 minutes of time almost due east, and nothing else that matches the description within several degrees of Swift's position, so a suggestion by Reinmuth that IC 4551 is a reobservation of NGC 5964 is generally (though not universally) accepted. (If not a duplicate entry, this must represent a nonexistent object, so those references that do not accept the identification list the object as nonexistent.)
Physical Information: Given the duplicate entry, see NGC 5964 for anything else.
SDSS image of region near the IC2 position for IC 4551, also showing NGC 5964
Above, a 2 degree wide SDSS image centered on the IC2 position for IC 4551, also showing NGC 5964

IC 4552 (probably = PGC 55687)
Recorded (Jun 21, 1897) by
Lewis Swift
A lost or nonexistent object in Serpens (RA 15 34 58.4, Dec +04 41 58)
or PGC 55687 = A magnitude 13.5? spiral galaxy (type S(rs)c?) in Serpens (RA 15 38 54.9, Dec +04 34 59)
Historical Identification: Per Dreyer, IC 4552 (= Swift list XI (#181), 1860 RA 15 28 01, NPD 84 49.8) is "extremely faint, pretty small, round". The position precesses to RA 15 34 58.4, Dec +04 41 58 (whence the position above), but there is nothing there, and almost all modern catalogs list the object as nonexistent. However, per Corwin, Swift's original note includes "near one of 6 or 8 stars in a curve", and on that basis he suggests that what Swift observed was U9945 (= PGC 55687). There are several fainter nebulae closer to Swift's position than PGC 55687, but none of them fits Swift's description of the field, so the object is almost certainly the galaxy listed above or (as noted first) lost or nonexistent. Note: The only other object recorded by Swift on that night is the lost or nonexistent IC 4540, so there may have been something wrong with Swift's use of his setting circles, and despite the large error in position required to attach PGC 55687 to IC 4552, it is not as unlikely as might be supposed.
Physical Information: Presuming IC 4552 = PGC 55687, its apparent size is 1.15 by 1.15 arcmin.
SDSS image of region near the IC2 position for the apparently nonexistent IC 4552
Above, a 12 arcmin wide SDSS image centered on the IC2 position for IC 4552
Below, a 12 arcmin wide SDSS image centered on PGC 55687
SDSS image of region near spiral galaxy PGC 55687, which may be the otherwise lost IC 4552
Below, a 1.5 arcmin wide SDSS image of PGC 55687
SDSS image of spiral galaxy PGC 55687, which may be the otherwise lost IC 4552
Below, a 24 arcmin wide SDSS image centered on PGC 55687; note the curved line of stars to its east
SDSS image of region near spiral galaxy PGC 55687, which may be the otherwise lost IC 4552, showing the curved line of stars that suggests that might be the case
Below, a 1.1 degree wide SDSS image showing PGC 55687 and Swift's position for IC 4552
SDSS image of region between the IC2 position for IC 4552 and spiral galaxy PGC 55687, which may be the otherwise nonexistent IC object

IC 4553 (=
IC 1127 = PGC 55497 = Arp 220)
Discovered (May 4, 1866) by Truman Safford (and later listed as IC 1127)
Discovered (Jul 25, 1903) by Stephane Javelle (and later listed as IC 4553)
A magnitude 13.2 spiral galaxy (type Scd? pec) in Serpens (RA 15 34 57.2, Dec +23 30 09)
Historical Identification: Per Dreyer, IC 4553 (= Javelle #1368, 1860 RA 15 28 52, NPD 66 02.3) is "faint, small, round, gradually brighter middle". The position precesses to RA 15 34 56.6, Dec +23 29 32, just below the southern outline of the galaxy listed above, and there is nothing of comparable brightness nearby, so the identification is certain. The duplicate entry was caused by Safford's position being only approximate, and off by a minute of time. Note: The galaxy is sometimes mis-listed as both IC 4553 and 4554, but the latter designation actually applies to the fainter galaxy to its southeast.
Physical Information: Given the duplicate entry, see IC 1127 for anything else.

IC 4554 (= PGC 214390)
Discovered (Jul 25, 1903) by
Stephane Javelle
A magnitude 15.9 spiral galaxy (type (SB0(r)a?) in Serpens (RA 15 35 04.9, Dec +23 28 45)
Historical Identification: Per Dreyer, IC 4554 (= Javelle #1369, 1860 RA 15 29 00, NPD 66 03.8) is "very faint, very small, nuclear, stellar". The position precesses to RA 15 35 04.7, Dec +23 28 04, only 0.7 arcmin south of the galaxy listed above, the description is appropriate, and the positional error is consistent with the one Javelle made for IC 4553, so the identification is certain. Despite that, IC 4554 is sometimes mis-listed as part of or equivalent to IC 4553 (which is actually the same as IC 1127).
Physical Information: Apparent size 0.5 by 0.5 arcmin.
SDSS image of region near lenticular galaxy IC 4554, also showing IC 1127, which is also known as Arp 220
Above, a 12 arcmin wide SDSS image centered on IC 4554, also showing IC 1127
Below, a 0.8 arcmin wide SDSS image of the galaxy
SDSS image of lenticular galaxy IC 4554

IC 4555 (probably = PGC 56077)
Discovered (Jul 20, 1900) by
DeLisle Stewart
A magnitude 12.8 spiral galaxy (type SB(s)cd?) in Apus (RA 15 48 14.6, Dec -78 10 44)
Historical Identification: Per Dreyer, IC 4555 (= DeLisle Stewart #423, 1860 RA 15 29 24, NPD 167 13) is "very faint, very small, extremely extended 55░, brighter middle". The position precesses to RA 15 47 59.6, Dec -77 40 04, but there is nothing there, nor anywhere near there in what is essentially a completely stellar field. However, there is what appears to be a suitable candidate (based on the description) 30 arcmin to the south; and although it is hard to see how such an error could have been made in measuring positions on a photographic plate, if the NPD were 167 43 the position would precess to 15 48 29.5, Dec -78 10 01, which lies on the northwestern edge of the galaxy listed above. So if we presume the positional error can be explained, then the identification becomes reasonably certain; as a result, this identification is generally (though not universally) accepted.
Physical Information: Apparent size 2.0 by 0.45 arcmin.
DSS image of region near Stewart's position for IC 4555
Above, a 12 arcmin wide region centered on Stewart's position for IC 4555
Below, a 12 arcmin wide DSS image centered on PGC 56077
DSS image of region near spiral galaxy PGC 56077, which is generally presumed to be IC 4555
Below, a 2.0 arcmin wide DSS image of the galaxy
DSS image of spiral galaxy PGC 56077, which is generally presumed to be IC 4555
Below, a 36 arcmin wide DSS image showing PGC 56077 and Stewart's position for IC 4555
(Rotated to match Stewart's 1900 Equinox)
DSS image of region between PGC 56077 and Stewart's position for IC 4555, rotated to match the 1900 Equinox

IC 4556 (= PGC 55523)
Discovered (Jul 24, 1903) by
Stephane Javelle
A magnitude 13.9 elliptical galaxy (type E2?) in Serpens (RA 15 35 22.5, Dec +25 17 50)
Historical Identification: Per Dreyer, IC 4556 (= Javelle #1370, 1860 RA 15 29 25, NPD 64 13.5) is "faint, small, round, nuclear". The position precesses to RA 15 35 23.8, Dec +25 18 25, barely beyond the northeastern outline of the galaxy listed above, and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 1.1 by 0.9 arcmin.
SDSS image of region near elliptical galaxy IC 4556, also showing IC 4558
Above, a 12 arcmin wide SDSS image centered on IC 4556, also showing IC 4558
Below, a 1.5 arcmin wide SDSS image of the galaxy
SDSS image of elliptical galaxy IC 4556

IC 4557 (= PGC 55483)
Discovered (Jul 24, 1903) by
Stephane Javelle
A magnitude 14.9 spiral galaxy (type S(r)a?) in Bo÷tes (RA 15 34 36.9, Dec +39 43 44)
Historical Identification: Per Dreyer, IC 4557 (= Javelle #1371, 1860 RA 15 29 31, NPD 49 48.6) is "faint, very small, nuclear". The position precesses to RA 15 34 36.1, Dec +39 43 16, less than half an arcmin southwest 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.
SDSS image of region near spiral galaxy IC 4557
Above, a 12 arcmin wide SDSS image centered on IC 4557
Below, a 0.6 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy IC 4557

IC 4558 (= PGC 55537)
Discovered (Jul 24, 1903) by
Stephane Javelle
A magnitude 14.6 spiral galaxy (type S(rs)a?) in Serpens (RA 15 35 46.2, Dec +25 20 45)
Historical Identification: Per Dreyer, IC 4558 (= Javelle #1372, 1860 RA 15 29 49, NPD 64 10.6) is "very faint, very small". The position precesses to RA 15 35 47.6, Dec +25 21 23, only 0.7 arcmin northeast of the galaxy listed above, and the relative positions and descriptions of IC 4558 and 4559 match their listed galaxies, so the identification is certain.
Physical Information: Apparent size 0.5 by 0.25 arcmin.
SDSS image of region near spiral galaxy IC 4558, also showing IC 4556 and IC 4559
Above, a 12 arcmin wide SDSS image centered on IC 4558, also showing IC 4556 and 4559
Below, a 0.6 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy IC 4558

IC 4559 (= PGC 55553)
Discovered (Jul 24, 1903) by
Stephane Javelle
A magnitude 14.3 lenticular galaxy (type S0/a?) in Serpens (RA 15 35 53.5, Dec +25 20 28)
Historical Identification: Per Dreyer, IC 4559 (= Javelle #1373, 1860 RA 15 29 57, NPD 64 10.9) is "faint, very small, round, nuclear". The position precesses to RA 15 35 55.5, Dec +25 21 06, only 0.8 arcmin northeast of the galaxy listed above, and the relative positions and descriptions of IC 4558 and 4559 match their listed galaxies, so the identification is certain.
Physical Information: Apparent size 0.7 by 0.6 arcmin.
SDSS image of region near lenticular galaxy IC 4559, also showing IC 4558
Above, a 12 arcmin wide SDSS image centered on IC 4559, also showing IC 4558
Below, a 1.0 arcmin wide SDSS image of the galaxy
SDSS image of lenticular galaxy IC 4559

WORKING HERE: tentative, pending receipt of clarification from Corwin

IC 4560 (probably = PGC 214393)
Discovered (Jul 24, 1903) by
Stephane Javelle
A magnitude 15.7 lenticular galaxy (type (R)S0/a?) in Bo÷tes (RA 15 35 54.1, Dec +39 48 51)
Historical Identification: Per Dreyer, IC 4560 (= Javelle #1374, 1860 RA 15 30 45, NPD 49 41.5) is "very faint, very small; (NGC) 5966 to southeast". The position precesses to RA 15 35 49.1, Dec +39 50 34, slightly northwest of a relatively tight grouping of two bright stars (BD+40 2903 and BD+40 2905), the fairly bright galaxy NGC 5966, and three substantially fainter galaxies, but it is not particularly close to any of them, and has no obvious association with any of them. Given the presence of NGC 5966, this is obviously the right "region", but none of the galaxies fits Javelle's description of his #1374 save for IC 4563, which is already accounted for by Javelle's separate observation of that object. And if NGC 5966 really were to the southeast of IC 4560, then the IC object would be to the northwest of NGC 5966, but there is nothing there but stars. So at first glance it appears that the object is lost or nonexistent, as stated in a previous version of this entry. However, per Corwin, Javelle became confused during his observations of IC 4560 and 4563, and used the southeastern of the two bright stars (BD+40 2905) for his offsets, but incorrectly stated that he used the northwestern (BD+40 2903) for his measurement of IC 4560. That means that his position should be off by approximately the difference in the positions of the two stars (only approximately because they both happen to be relatively high-proper-motion stars, and are not in exactly the same position relative to each other and the neighboring field as they were in 1903). The arrows drawn in the first image below show the current offset in the stars' positions, and the corresponding change in the position of IC 4560, which places it right on top of PGC 214393, making that by far the best candidate for the IC object. There remains the problem that it is far fainter than might be expected based on its description, and is in the wrong position relative to NGC 5966, hence my decision to state that it is "probably" = IC 4560; but no one has come up with a better suggestion, so for better or worse that is almost certainly the way things will remain.
Physical Information: PGC 214393's apparent size is 0.45 by 0.25 arcmin.
SDSS image of region near Javelle's position for IC4560, showing NGC 5966, IC 4563, and PGC 214393, which is the most likely candidate for IC 4560
Above, a 12 arcmin wide SDSS image centered on the IC2 position for IC 4560
Also shown are NGC 5966, IC 4563 and PGC 214393, and the "correction" in position
Below, a 12 arcmin wide SDSS image centered on PGC 214393, based on the presumption it is IC 4560
Also shown are NGC 5966 and IC 4563
SDSS image of region near lenticular galaxy PGC 214393, which is the most likely candidate for IC 4560, also showing NGC 5966 and IC 4563
Below, a 0.6 arcmin wide SDSS image of PGC 214393, which is the most likely candidate for IC 4560
(The image is heavily contaminated by glare from the star to its northeast)
SDSS image of lenticular galaxy PGC 214393, which is the most likely candidate for IC 4560

IC 4561 (= PGC 55610)
Discovered (Jul 24, 1903) by
Stephane Javelle
A magnitude 14.4 lenticular galaxy (type S0/a?) in Serpens (RA 15 36 47.1, Dec +25 25 00)
Historical Identification: Per Dreyer, IC 4561 (= Javelle #1375, 1860 RA 15 30 50, NPD 64 07.5) is "faint, very small, round, nuclear". The position precesses to RA 15 36 48.1, Dec +25 24 39, barely off the southern end of the galaxy listed above, and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 0.7 by 0.45 arcmin.
SDSS image of region near lenticular galaxy IC 4561
Above, a 12 arcmin wide SDSS image centered on IC 4561
Below, a 0.8 arcmin wide SDSS image of the galaxy
SDSS image of lenticular galaxy IC 4561

IC 4562 (= PGC 55559)
Discovered (Aug 20, 1890) by
Edward Barnard
A magnitude 12.6 elliptical galaxy (type E0?) in Bo÷tes (RA 15 35 57.1, Dec +43 29 35)
Historical Identification: Per Dreyer, IC 4562 (= Barnard (A.N.) 4136, 1860 RA 15 30 52, NPD 46 06) is "pretty bright, small, round, much brighter middle, faint star or nebula 1 arcmin to northeast". The position precesses to RA 15 35 39.1, Dec +43 26 04, but the nearest galaxy of any consequence is nearly 5 arcmin to the northeast. The problem is that Barnard did not give positions for the five objects he found in this region, merely posting some notes about the objects and a sketch of the area, and Dreyer had to estimate their positions from that sketch. However, the relative positions of the objects in the sketch correspond reasonably well to the relative positions of the brighter galaxies in the region, so the identity of all five objects is absolutely certain, despite any errors Dreyer made in estimating their positions. (In the case of IC 4562, "the nearest galaxy of any consequence" mentioned above happens to be the galaxy corresponding to the IC object, so Dreyer's 5 arcmin error wasn't that bad, after all.)
Physical Information: Apparent size 1.5 by 1.5 arcmin.
Barnard's sketch of the region near IC 4562, IC 4564, IC 4565, IC 4566 and IC 4567
Above, Barnard's sketch of the region containing IC 4562, 4564, 4565, 4566 and 4567
Below, a 20 arcmin wide SDSS image centered on IC 4565, showing Barnard's discoveries
SDSS image of the region near IC 4562, IC 4564, IC 4565, IC 4566 and IC 4567
Below, a 12 arcmin wide SDSS image centered on IC 4562, also showing IC 4564 and PGC 55563
SDSS image of region near elliptical galaxy IC 4562, also showing IC 4564 and PGC 55563, which is sometimes called IC 4562A
Below, a 1.5 arcmin wide SDSS image of the galaxy
SDSS image of elliptical galaxy IC 4562

PGC 55563 (= "IC 4562A")
Not an IC object but listed here since sometimes called IC 4562A due to proximity to
IC 4562
A magnitude 14.4 lenticular galaxy (type E/S0??) in Bo÷tes (RA 15 36 02.8, Dec +43 30 12)
Historical Identification: Although not an IC object, PGC 55563 is the "faint star or nebula 1 arcmin to northeast" of IC 4562, so although its occasional designation as IC 4562A is needlessly confusing, the galaxy does deserve some note.
Physical Information: Apparent size 0.55 by 0.55 arcmin.
SDSS image of lenticular galaxy PGC 55563, which is sometimes called IC 4562A
Above, a 0.6 arcmin wide SDSS image of PGC 55563; for a wider view see IC 4562

IC 4563 (= PGC 55565)
Discovered (Jul 24, 1903) by
Stephane Javelle
A magnitude 14.3 spiral galaxy (type SBb?) in Bo÷tes (RA 15 36 03.7, Dec +39 49 53)
Historical Identification: Per Dreyer, IC 4563 (= Javelle #1376, 1860 RA 15 30 56, NPD 49 40.6) is "very faint, very small, nuclear". The position precesses to RA 15 35 59.9, Dec +39 51 30, about 1.8 arcmin northwest of the galaxy listed above. Given the fact that there is nothing else nearby that fits the description, the identification would be reasonably certain even without any additional information; but per Corwin, Javelle mixed up the identifications for the two stars in the area, using the southeastern as his comparison star, but with the coordinates for the northwestern star. Correcting for that mistake puts the position right on the galaxy, making the identification certain. (A similar error probably crept into Javelle's measurements for IC 4560, but in that case there is no way to fit its description to any of the galaxies in the region.)
Physical Information: Apparent size 0.8 by 0.4 arcmin.
SDSS image of region near spiral galaxy IC 4563, also showing NGC 5966
Above, a 12 arcmin wide SDSS image centered on IC 4563, also showing NGC 5966
Below, a 1.0 arcmin wide SDSS image of the galaxy (heavily contaminated by glare)
SDSS image of spiral galaxy IC 4563

IC 4564 (= PGC 55584)
Discovered (Aug 20, 1890) by
Edward Barnard
A magnitude 13.5 spiral galaxy (type Sbc?) in Bo÷tes (RA 15 36 27.1, Dec +43 31 07)
Historical Identification: Per Dreyer, IC 4564 (= Barnard (A.N.) 4136, 1860 RA 15 31 48, NPD 46 01) is "pretty faint, round, gradually brighter middle". The position precesses to RA 15 36 34.2, Dec +43 31 13, between two apparently equally good candidates. However, as discussed in the entry for IC 4562, Barnard's sketch of the region makes the identification of IC 4564 as the galaxy listed above absolutely certain.
Physical Information: Apparent size 1.4 by 0.5 arcmin.
SDSS image of spiral galaxy IC 4564, also showing IC 4562, IC 4565 and IC 4566
Above, a 12 arcmin wide SDSS image centered on IC 4564, also showing IC 4562, 4565 and 4566
Below, a 1.5 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy IC 4564

IC 4565 (= PGC 55592)
Discovered (Aug 20, 1890) by
Edward Barnard
A magnitude 14.1 spiral galaxy (type SABcd?) in Bo÷tes (RA 15 36 35.2, Dec +43 25 30)
Historical Identification: Per Dreyer, IC 4565 (= Barnard (A.N.) 4136, 1860 RA 15 32 00, NPD 46 08) is "faint, round, gradually brighter middle". The position precesses to RA 15 36 46.7, Dec +43 24 25, over 2 arcmin southeast of the galaxy listed above, but as discussed in the entry for IC 4562, given the method Dreyer used to obtain the position it is "good", and in any event Barnard's sketch of the region makes the identification absolutely certain.
Physical Information: Apparent size 0.95 by 0.5 arcmin. Listed as a starburst galaxy, but there is no sign of that in its image.
SDSS image of spiral galaxy IC 4565, also showing IC 4564
Above, a 12 arcmin wide SDSS image centered on IC 4565, also showing IC 4564
Below, a 1.0 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy IC 4565

IC 4566 (= PGC 55601)
Discovered (Aug 20, 1890) by
Edward Barnard
A magnitude 13.3 spiral galaxy (type SBab?) in Bo÷tes (RA 15 36 42.2, Dec +43 32 22)
Historical Identification: Per Dreyer, IC 4566 (= Barnard (A.N.) 4136, 1860 RA 15 32 27, NPD 46 00) is "pretty faint, round, gradually brighter middle". The position precesses to RA 15 37 12.9, Dec +43 32 19, about 9.5 arcmin due east of the galaxy listed above, but as discussed in the entry for IC 4562, Barnard's sketch of the region makes the identification absolutely certain despite the error in Dreyer's estimated position.
Physical Information: Apparent size 2.05 by 1.05 arcmin.
SDSS image of spiral galaxy IC 4566, also showing IC 4564
Above, a 12 arcmin wide SDSS image centered on IC 4566, also showing IC 4564
Below, a 2.0 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy IC 4566

IC 4567 (= PGC 55620)
Discovered (Aug 20, 1890) by
Edward Barnard
A magnitude 12.8 spiral galaxy (type SABcd?) in Bo÷tes (RA 15 37 13.3, Dec +43 17 54)
Historical Identification: Per Dreyer, IC 4567 (= Barnard (A.N.) 4136, 1860 RA 15 32 44, NPD 46 16) is "pretty faint, round, gradually brighter middle". The position precesses to RA 15 37 31.1, Dec +43 16 22, about 3.5 arcmin southeast of the galaxy listed above, but as discussed in the entry for IC 4562, Barnard's sketch of the region makes the identification absolutely certain despite the error in Dreyer's estimated position.
Physical Information: Apparent size 1.5 by 1.0 arcmin. A starburst galaxy.
SDSS image of spiral galaxy IC 4567
Above, a 12 arcmin wide SDSS image centered on IC 4567
Below, a 2.0 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy IC 4567

IC 4568 (= PGC 55746)
Discovered (Jul 25, 1895) by
Stephane Javelle
A magnitude 14.5 spiral galaxy (type S(rs)b?) in Corona Borealis (RA 15 40 07.7, Dec +28 09 08)
Historical Identification: Per Dreyer, IC 4568 (= Javelle #1377, 1860 RA 15 34 20, NPD 61 23.7) is "faint, small, round, nuclear". The position precesses to RA 15 40 08.2, Dec +28 09 01, on the eastern rim of the galaxy listed above, and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 0.7 by 0.3 arcmin.
SDSS image of region near spiral galaxy IC 4568
Above, a 12 arcmin wide SDSS image centered on IC 4568
Below, a 0.8 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy IC 4568

IC 4569 (= PGC 55783)
Discovered (Jul 25, 1895) by
Stephane Javelle
A magnitude 14.0 lenticular galaxy (type S0/a?) in Corona Borealis (RA 15 40 48.4, Dec +28 17 31)
Historical Identification: Per Dreyer, IC 4569 (= Javelle #1378, 1860 RA 15 34 59, NPD 61 15.3) is "pretty bright, double star of 13th magnitude in small nebula". The position precesses to RA 15 40 46.6, Dec +28 17 31, near the western rim of the galaxy listed above, and there is nothing else nearby, so the identification is certain. (The reference to a double star seems odd, but depending upon seeing, the nucleus might have appeared double.)
Physical Information: Apparent size 0.85 by 0.65 arcmin.
SDSS image of region near lenticular galaxy IC 4569
Above, a 12 arcmin wide SDSS image centered on IC 4569
Below, a 1.0 arcmin wide SDSS image of the galaxy
SDSS image of lenticular galaxy IC 4569

IC 4570 (= PGC 55797)
Discovered (Jul 24, 1895) by
Stephane Javelle
A magnitude 14.1 spiral galaxy (type SABcd?) in Corona Borealis (RA 15 41 22.6, Dec +28 13 47)
Historical Identification: Per Dreyer, IC 4570 (= Javelle #1379, 1860 RA 15 35 35, NPD 61 19.1) is "faint, considerably small, round". The position precesses to RA 15 41 22.6, Dec +28 13 49, right on the galaxy listed above, and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 0.8 by 0.75 arcmin.
SDSS image of region near spiral galaxy IC 4570
Above, a 12 arcmin wide SDSS image centered on IC 4570
Below, a 1.0 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy IC 4570

IC 4571 (= PGC 56106)
Discovered (Jul 19, 1900) by
DeLisle Stewart
A magnitude 12.6 spiral galaxy (type SB(rs)b? pec) in Triangulum Australe (RA 15 48 51.6, Dec -67 19 25)
Historical Identification: Per Dreyer, IC 4571 (= DeLisle Stewart #424, 1860 RA 15 35 39, NPD 156 52) is "considerably faint, extremely small, much extended 155░". The position precesses to RA 15 48 54.4, Dec -67 18 27, only an arcmin north of the galaxy listed above, the description fits, and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 1.6 by 0.6 arcmin.
DSS image of region near spiral galaxy IC 4571
Above, a 12 arcmin wide DSS image centered on IC 4571
Below, a 1.5 arcmin wide DSS image of the galaxy
DSS image of spiral galaxy IC 4571

IC 4572 (= PGC 55817)
Discovered (Jul 24, 1895) by
Stephane Javelle
A magnitude 13.7 spiral galaxy (type SB(r)a?) in Corona Borealis (RA 15 41 54.2, Dec +28 08 02)
Historical Identification: Per Dreyer, IC 4572 (= Javelle #1380, 1860 RA 15 36 07, NPD 61 24.9) is "pretty bright, considerably small, gradually brighter middle, diffuse, mottled but not resolved". The position precesses to RA 15 41 54.8, Dec +28 08 07, right on the galaxy listed above, so the identification is certain.
Physical Information: Apparent size 1.1 by 0.7 arcmin.
SDSS image of region near spiral galaxy IC 4572
Above, a 12 arcmin wide SDSS image centered on IC 4572
Below, a 1.2 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy IC 4572

IC 4573 (= PGC 55825)
Discovered (Apr 7, 1900) by
Stephane Javelle
A magnitude 14.7 spiral galaxy (type Sc?) in Serpens (RA 15 42 12.3, Dec +23 48 00)
Historical Identification: Per Dreyer, IC 4573 (= Javelle #1381, 1860 RA 15 36 08, NPD 65 45.8) is "faint, very small, diffuse, mottled but not resolved". The position precesses to RA 15 42 10.2, Dec +23 47 14, about 0.9 arcmin southwest of the galaxy listed above. This is the same error Javelle made for IC 4575, discovered on the same night, suggesting a common source of error in measuring their positions, and makes the identification of the two galaxies as the two IC entries essentially certain.
Physical Information: Apparent size 0.6 by 0.3 arcmin.
SDSS image of region near spiral galaxy IC 4573, also showing IC 4575
Above, a 12 arcmin wide SDSS image centered on IC 4573, also showing IC 4575
Below, a 0.6 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy IC 4573

IC 4574 (= PGC 55820)
Discovered (Jul 25, 1895) by
Stephane Javelle
A magnitude 14.8 spiral galaxy (type SBbc?) in Corona Borealis (RA 15 41 59.2, Dec +28 14 25)
Historical Identification: Per Dreyer, IC 4574 (= Javelle #1382, 1860 RA 15 36 12, NPD 61 18.4) is "pretty faint, small, round". The position precesses to RA 15 41 59.4, Dec +28 14 37, right on the galaxy listed above, so the identification is certain.
Physical Information: Apparent size 0.75 by 0.4 arcmin.
SDSS image of region near spiral galaxy IC 4574
Above, a 12 arcmin wide SDSS image centered on IC 4574
Below, a 0.8 arcmin SDSS image of the galaxy
SDSS image of spiral galaxy IC 4574

IC 4575 (= PGC 55828)
Discovered (Apr 7, 1900) by
Stephane Javelle
A magnitude 14.6 spiral galaxy (type SB(r)b?) in Serpens (RA 15 42 19.7, Dec +23 48 27)
Historical Identification: Per Dreyer, IC 4575 (= Javelle #1383, 1860 RA 15 36 15, NPD 65 45.3) is "faint, small, diffuse, mottled but not resolved, 15th magnitude star attached". The position precesses to RA 15 42 17.2, Dec +23 47 45, about 0.9 arcmin southwest of the galaxy listed above. This is the same error Javelle made for IC 4573, discovered on the same night, suggesting a common source of error in measuring their positions, and makes the identification of the two galaxies as the two IC entries essentially certain.
Physical Information: Apparent size 0.75 by 0.5 arcmin.
SDSS image of region near spiral galaxy IC 4575, also showing IC 4573 and IC 4577
Above, a 12 arcmin wide SDSS image centered on IC 4575, also showing IC 4573 and 4577
Below, a 1.0 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy IC 4575

IC 4576 (= PGC 55840)
Discovered (Jul 15, 1903) by
Stephane Javelle
A magnitude 13.9 lenticular galaxy (type S0?) in Serpens (RA 15 42 35.5, Dec +23 40 14)
Historical Identification: Per Dreyer, IC 4576 (= Javelle #1384, 1860 RA 15 36 31, NPD 65 52.1) is "faint, very small, round, nuclear, 14th magnitude star to northwest". The position precesses to RA 15 42 33.5, Dec +23 41 00, less than an arcmin northwest of the galaxy listed above, and the star to its northwest makes the identification certain.
Physical Information: Apparent size 1.1 by 0.75 arcmin.
SDSS image of region near lenticular galaxy IC 4576
Above, a 12 arcmin wide SDSS image centered on IC 4576
Below, a 1.5 arcmin wide SDSS image of the galaxy
SDSS image of lenticular galaxy IC 4576

IC 4577 (= PGC 55848)
Discovered (Apr 7, 1900) by
Stephane Javelle
A magnitude 14.3 lenticular galaxy (type S0?) in Serpens (RA 15 42 45.6, Dec +23 47 33)
Historical Identification: Per Dreyer, IC 4577 (= Javelle #1385, 1860 RA 15 36 41, NPD 65 46.3) is "faint, small, round, gradually brighter middle, mottled but not resolved". The position precesses to RA 15 42 43.1, Dec +23 46 49, about 0.9 arcmin southwest of the galaxy listed above. This error is shared by nearby IC 4579, and for that matter by practically all the objects found by Javelle on April 7, 1900; and its consistency makes the identification certain.
Physical Information: Apparent size 0.6 by 0.6 arcmin.
SDSS image of region near lenticular galaxy IC 4577, also showing IC 4575 and IC 4579
Above, a 12 arcmin wide SDSS image centered on IC 4577, also showing IC 4575 and IC 4579
Below, a 1.0 arcmin wide SDSS image of the galaxy
SDSS image of lenticular galaxy IC 45779

IC 4578 (= PGC 56305)
Discovered (Jul 21, 1900) by
DeLisle Stewart
A magnitude 13.1 spiral galaxy (type (R')SB(s)b?) in Apus (RA 15 53 10.7, Dec -74 49 30)
Historical Identification: Per Dreyer, IC 4578 (= DeLisle Stewart #425, 1860 RA 15 36 44, NPD 164 23) is "extremely faint, extremely small, considerably extended 140░, between two very faint stars". The position precesses to RA 15 53 19.1, Dec -74 48 59, only 0.7 arcmin northeast of the galaxy listed above, and the description fits, so the identification is certain.
Physical Information: Apparent size 1.0 by 0.35 arcmin.
DSS image of region near spiral galaxy IC 4578
Above, a 12 arcmin wide DSS image centered on IC 4578
Below, a 1.2 arcmin wide DSS image of the galaxy
DSS image of spiral galaxy IC 4578

IC 4579 (= PGC 55852)
Discovered (Apr 7, 1900) by
Stephane Javelle
A magnitude 14.9 lenticular galaxy (type S0?) in Serpens (RA 15 42 51.5, Dec +23 46 23)
Historical Identification: Per Dreyer, IC 4579 (= Javelle #1386, 1860 RA 15 36 47, NPD 65 47.5) is "faint, small, round, gradually brighter middle, mottled but not resolved". The position precesses to RA 15 42 49.2, Dec +23 45 38, about 0.9 arcmin southwest of the galaxy listed above. This error is shared by nearby IC 4577, and for that matter by practically all the objects found by Javelle on April 7, 1900; and its consistency makes the identification certain.
Physical Information: Apparent size 0.6 by 0.45 arcmin.
SDSS image of region near lenticular galaxy IC 4579, also showing IC 4577
Above, a 12 arcmin wide SDSS image centered on IC 4579, also showing IC 4577
Below, a 0.8 arcmin wide SDSS image of the galaxy
SDSS image of lenticular galaxy 4579

IC 4580 (= PGC 55862)
Discovered (Jul 26, 1895) by
Stephane Javelle
A magnitude 14.5 spiral galaxy (type SB(r)a?) in Corona Borealis (RA 15 43 14.3, Dec +28 21 24)
Historical Identification: Per Dreyer, IC 4580 (= Javelle #1387, 1860 RA 15 37 28, NPD 61 10.9) is "faint, small, round". The position precesses to RA 15 43 14.7, Dec +28 22 20, less than an arcmin north of the galaxy listed above, and there is nothing else nearby, so the identification is certain.
Physical Information: Apparent size 0.75 by 0.35 arcmin.
SDSS image of region near spiral galaxy IC 4580
Above, a 12 arcmin wide SDSS image centered on IC 4580
Below, a 0.8 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy IC 4580

IC 4581 (= PGC 55893)
Discovered (Jul 26, 1895) by
Stephane Javelle
A magnitude 14.4 spiral galaxy (type SB(rs)c?) in Corona Borealis (RA 15 44 01.5, Dec +28 16 37)
Historical Identification: Per Dreyer, IC 4581 (= Javelle #1388, 1860 RA 15 38 15, NPD 61 15.7) is "faint, small, irregular figure, 12.5 magnitude star near". The position precesses to RA 15 44 01.7, Dec +28 17 40, only an arcmin north of the galaxy listed above, there is nothing else nearby, and the star just south of the galaxy makes the identification certain.
Physical Information: Apparent size 0.8 by 0.7 arcmin. A starburst galaxy?
SDSS image of region near spiral galaxy IC 4581
Above, a 12 arcmin wide SDSS image centered on IC 4581
Below, a 1.0 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy IC 4581

IC 4582 (= PGC 55967)
Discovered (Jul 26, 1895) by
Stephane Javelle
A magnitude 14.0 spiral galaxy (type SBbc?) in Corona Borealis (RA 15 45 39.4, Dec +28 05 20)
Historical Identification: Per Dreyer, IC 4582 (= Javelle #1389, 1860 RA 15 39 49, NPD 61 29.0) is "faint, small, extended east-west, gradually brighter middle, 12.5 magnitude star 6.5 seconds of time to east". The position precesses to RA 15 45 36.1, Dec +28 04 38, only an arcmin southwest of the galaxy listed above. The galaxy extends north-south rather than east-west, but there is nothing else nearby, and the star just over 6 seconds of time to the east makes the identification certain.
Physical Information: Apparent size 1.4 by 0.45 arcmin. Probably a starburst galaxy.
SDSS image of region near spiral galaxy IC 4582
Above, a 12 arcmin wide SDSS image centered on IC 4582
Below, a 1.5 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy IC 4582

IC 4583 (= PGC 55999)
Discovered (Jul 15, 1903) by
Stephane Javelle (1390)
A magnitude 14.3 spiral galaxy (type Sab?) in Serpens (RA 15 46 21.9, Dec +23 48 32)
Historical Identification: Per Dreyer, IC 4583 (= Javelle #1390, 1860 RA 15 40 23, NPD 65 45.7) is "faint, very small, extended, nuclear, mottled but not resolved". The position precesses to RA 15 46 24.3, Dec +23 48 03, only 0.7 arcmin 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 1.1 by 0.3 arcmin.
SDSS image of region near spiral galaxy IC 4583
Above, a 12 arcmin wide SDSS image centered on IC 4583
Below, a 1.2 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy IC 4583

IC 4584 (= PGC 56627)
Discovered (Jul 19, 1900) by
DeLisle Stewart
A magnitude 15.1 spiral galaxy (type SA(rs)cd?) in Triangulum Australe (RA 16 00 12.5, Dec -66 22 59)
Historical Identification: Per Dreyer, IC 4584 (= DeLisle Stewart #426, 1860 RA 15 46 52, NPD 155 58) is "extremely faint, small, irregular figure". The position precesses to RA 16 00 03.0, Dec -66 22 32, on the northwestern rim of the galaxy listed above, and the only other galaxy in the field is properly accounted for as IC 4585, so the identification is certain.
Physical Information: Apparent size 1.9 by 1.35 arcmin.
DSS image of region near spiral galaxy IC 4584, also showing IC 4585
Above, a 12 arcmin wide DSS image centered on IC 4584, also showing IC 4585
Below, a 2.4 arcmin wide DSS image of the galaxy
DSS image of spiral galaxy IC 4584

IC 4585 (= PGC 56630)
Discovered (Jul 19, 1900) by
DeLisle Stewart
A magnitude 12.3 spiral galaxy (type SB(s)b?) in Triangulum Australe (RA 16 00 17.0, Dec -66 19 19)
Historical Identification: Per Dreyer, IC 4585 (= DeLisle Stewart #427, 1860 RA 15 46 58, NPD 155 55) is "extremely faint, small, irregular figure". The position precesses to RA 16 00 08.2, Dec -66 19 31, on the southwestern arm of the galaxy listed above, and the only other galaxy in the field is properly accounted for as IC 4584, so the identification is certain.
Physical Information: Apparent size 3.0 by 0.65 arcmin.
DSS image of region near spiral galaxy IC 4585, also showing IC 4584
Above, a 12 arcmin wide DSS image centered on IC 4585, also showing IC 4584
Below, a 2.4 arcmin wide DSS image of the galaxy
DSS image of spiral galaxy IC 4585

IC 4586 (=
NGC 6014 = PGC 56413)
Discovered (Apr 24, 1830) by John Herschel (and later listed as NGC 6014)
Rediscovered (Aug 19, 1897) by Lewis Swift (and later listed as IC 4586)
A magnitude 12.2 lenticular galaxy (type S0?) in Serpens (RA 15 55 57.5, Dec +05 55 54)
Historical Identification: Per Dreyer, IC 4586 (= Swift list XII (#13), 1860 RA 15 48, NPD 83 33.7) is "extremely faint, small, round, between 8th magnitude star to east and curve of stars to west". The position precesses to RA 15 54 53, Dec +06 01 25, but (as often occurs for Swift's later measurements) there is nothing there. However, per Corwin, a 1940 suggestion by Carlson that IC 4586 is equivalent to NGC 6014 is almost certainly correct, as the description of the field perfectly fits the NGC object, as shown in the image below. So despite an error of a minute of time (= 15 arcmin) in right ascension and 6 arcmin in declination, the identification seems certain.
Physical Information: Given the duplicate entry, see NGC 6014 for anything else.
SDSS image of region near NGC 6014, showing the stars preceding and following it that confirm its equivalence to IC 4586
     Above, a 22 arcmin wide SDSS image showing the "8th magnitude star to east and curve of stars to west" of NGC 6014, thereby confirming its equivalence to IC 4586.

IC 4587 (= PGC 56614)
Discovered (Aug 27, 1903) by
Edward Barnard
A magnitude 14.3 elliptical galaxy (type E0?) in Corona Borealis (RA 15 59 51.6, Dec +25 56 26)
Historical Identification: Per Dreyer, IC 4587 (= Barnard, 1860 RA 15 54 00, NPD 63 39.6) is "extremely faint, extremely small, T Coronae to southwest". The position precesses to RA 15 59 51.4, Dec +25 56 28, right on the galaxy listed above, and T Coronae Borealis is a few arcmin to the southwest, so the identification is certain.
Physical Information: Apparent size 0.5 by 0.5 arcmin.
SDSS image of region near elliptical galaxy IC 4587
Above, a 12 arcmin wide SDSS image centered on IC 4587
Below, a 0.8 arcmin wide SDSS image of the galaxy
SDSS image of elliptical galaxy IC 4587

IC 4588 (= PGC 57025)
Discovered (Jul 15, 1903) by
Stephane Javelle
A magnitude 15.0 elliptical galaxy (type E0?) in Serpens (RA 16 05 04.2, +23 55 02)
Historical Identification: Per Dreyer, IC 4588 (= Javelle #1391, 1860 RA 15 59 07, NPD 65 42.2) is "very faint, very small, round, stellar, (NGC) 5051 to west" (5051 is a typographical error for 6051). The position precesses to RA 16 05 04.4, Dec +23 54 47, on the southern border of the galaxy listed above and NGC 6051 is just to the west, so the identification is certain.
Physical Information: Based on a recessional velocity of 15945 km/sec, a straightforward calculation indicates that IC 4588 is about 740 million light years away. However, for such distant objects, we must take into account the expansion of the Universe during the time it took their light to reach us. Doing that shows that IC 4588 was about 700 million light years away when the light by which we see it was emitted, about 715 million years ago (the difference between the two numbers is due to the expansion of the intervening space during the light-travel time). Given that and its 0.5 by 0.4 arcmin apparent size, the galaxy is about 100 thousand light years across. (Note: A Wikisky search for IC 4588 shows NGC 6051. A search using the PGC listing or its coordinates shows the correct object.)
SDSS image of region near elliptical galaxy IC 4588, also showing NGC 6051
Above, a 12 arcmin wide SDSS image centered on IC 4588, also showing NGC 6051
Below, a 0.8 arcmin wide SDSS image of the galaxy
SDSS image of elliptical galaxy IC 4588

IC 4589
Recorded (Jun 19, 1890) by
Guillaume Bigourdan
A magnitude 15(?) star in Ophiuchus (RA 16 07 24.7, Dec -06 23 08)
Historical Identification: Per Dreyer, IC 4589 (= Bigourdan #323, 1860 RA 15 59 57, NPD 96 00) is a "13th magnitude star, perhaps in extremely faint nebula". The position precesses to RA 16 07 25.0, Dec -06 22 44, just over a third of an arcmin north of the star listed above. Per Thomson, Bigourdan stated that the star was accompanied by another star about an arcmin to the west (at position angle 265░), and the presence of that star makes the identification of the star in question certain. This situation, in which Bigourdan thought a star might be accompanied by a faint nebula, almost always resulted in an IC entry for a star without a nebula; so given the description, the result is more typical than not.
DSS image of region centered on the star listed as IC 4589
Above, a 12 arcmin wide DSS image centered on the star listed as IC 4589

IC 4590 (= PGC 57260)
Discovered (Jul 26, 1895) by
Stephane Javelle (1392)
A magnitude 14.7 lenticular galaxy (type E/S0?) in Corona Borealis (RA 16 08 21.2, Dec +28 28 43)
Historical Identification: Per Dreyer, IC 4590 (= Javelle #1392, 1860 RA 16 02 41, NPD 61 08.6) is "faint, small, gradually brighter middle, diffuse". The position precesses to RA 16 08 21.5, Dec +28 29 00, near the northern boundary of the galaxy listed above, and there is nothing of comparable brightness nearby, so the identification is certain. Note: Although the galaxy appears to be accompanied by a pair of very faint companions, the northern one is a star, and the southern one is not part of the IC entry, as it is too faint to have affected Javelle's observation.
Physical Information: Apparent size 0.55 by 0.45 arcmin.
SDSS image of region near lenticular galaxy IC 4590
Above, a 12 arcmin wide SDSS image centered on IC 4590
Below, a 0.8 arcmin wide SDSS image of the galaxy
SDSS image of lenticular galaxy IC 4590

IC 4591 (= LBN 1096)
Discovered (Mar 23, 1895) by
Edward Barnard
A magnitude 5 star (13 Sco) and reflection nebula in Scorpius (RA 16 12 18.2, Dec -27 55 35)
Historical Identification: Per Dreyer, IC 4591 (= Barnard (A. N.) 3301, 1860 RA 16 03 41, NPD 117 34) is a "5.6 magnitude star in faint nebula". The position precesses to RA 16 12 18.2, Dec -27 55 58, almost dead center on 5th magnitude 13 Scorpii. Per Corwin, Dreyer's positions were for the stars lighting up the reflection nebula, so the identification of the star (and by extension, the surrounding nebula) is certain, and the modern position listed above is the position of the star.
Physical Information:
DSS image of region near 13 Scorpii and the reflection nebula listed as IC 4591
Above, a 30 arcmin wide DSS image centered on IC 4591

IC 4592 (= LBN 1113)
Discovered (Mar 23, 1895) by
Edward Barnard
A magnitude 4 star (ν Sco) and reflection nebula in Scorpius (RA 16 11 59.7, Dec -19 27 59)
Historical Identification: Per Dreyer, IC 4592 (= Barnard (A. N.) 3301, 1860 RA 16 03 52, NPD 109 06) is "very large, extended, ν2 Scorpii involved". The position precesses to RA 16 12 00.1, Dec -19 27 58, just northwest of ν Scorpii. Per Corwin, Dreyer's positions were for the stars lighting up the reflection nebula, so the identification of the star (and by extension, the surrounding nebula) is certain, and the modern position listed above is the position of the star.
Physical Information: Apparent size 150 by 60 arcmin?
DSS image of Nu Scorpii and the reflection nebula listed as IC 4592, partially overlaid on an image by Jim Misti, Steve Mazlin and Robert Gendler to remove a 'ghost' image caused by another star
Above, a 2 degree wide DSS image centered on IC 4592
(partially overlaid with a Wikisky cutout to remove a "ghost" image of a bright star)

IC 4593
Discovered (1907) by
Williamina Fleming
A magnitude 10.7 planetary nebula in Hercules (RA 16 11 44.5, Dec +12 04 16)
Historical Identification: Per Dreyer, IC 4593 (= Fleming #108, 1860 RA 16 05 07, NPD 77 34) is "planetary, stellar". The position precesses to RA 16 11 41.4, Dec +12 04 07, just west of the planetary nebula listed above, and since there is no similar object in the region, the identification is certain.
Physical Information: Apparent size of fainter, outer shell about 0.6 by 0.6 arcmin; of brighter inner structure about 0.55 by 0.3 arcmin.
SDSS image of region near planetary nebula IC 4593
Above, a 12 arcmin wide SDSS image centered on IC 4593
Below, a 1.0 arcmin wide SDSS image of the planetary nebula
SDSS image of planetary nebula IC 4593
Below, a 0.6 arcmin wide HST image of the nebula
(Image Credit NASA/ESA & The Hubble Heritage Team (STScI/AURA))
HST image of planetary nebula IC 4593

IC 4594 (=
NGC 6075 = PGC 57426, and not = PGC 1691585)
Discovered (Jun 27, 1881) by ╔douard Stephan (and later listed as NGC 6075)
Discovered (Jul 20, 1903) by Stephane Javelle (and later listed as IC 4594)
A magnitude 13.9 lenticular galaxy (type E/S0?) in Hercules (RA 16 11 22.6, Dec +23 57 54)
Historical Identification: Per Dreyer, IC 4594 (= Javelle #1393, 1860 RA 16 05 23, NPD 65 58.3) is "faint, small, round, nuclear, mottled but not resolved". The position precesses to RA 16 11 20.2, Dec +23 39 48, about an arcmin southeast of PGC 1691585, which is therefore sometimes listed as IC 4594 (and for that reason, is discussed in the entry immediately below). However, that galaxy is almost certainly too faint for Javelle to have noticed, so the more likely identification is one suggested by Steinicke, then adopted by Corwin Ś namely, that Javelle reversed the sign of his approximately 9 arcmin offset in declination, which (when corrected) puts the position right on the much brighter NGC 6075. Because of this, early on almost all catalogs had no entry for IC 4594 or listed it as "not found"; more recently PGC 1691585 began to pop up as the identification, and now almost all catalogs list IC 4594 as a duplicate of NGC 6075. (However, Thomson makes the argument that if Javelle actually observed NGC 6075, he would have realized it, and not presented his observation as a "nova"; and I agree that if he had known that he was observing something in the same region as that galaxy, he might well have realized the duplication. But with a 9 arcmin offset, he probably had no idea what he was looking at until after he finished his reductions, at which point the 18 arcmin error in position would have made it impossible for him (or Dreyer) to realize the truth of the matter.)
Physical Information: Given the duplicate entry, see NGC 6075 for anything else.

PGC 1691585 (almost certainly not =
IC 4594)
Not an IC object but listed here since sometimes misidentified as IC 4594
A magnitude 17(?) spiral galaxy (type Sab?) in Hercules (RA 16 11 24.5, Dec +23 40 28)
Historical Identification: (Usually listed as 2MASX J16112451+2340283.) See IC 4594 for a discussion of why this was once thought to be IC 4594, but is now almost universally abandoned as a candidate for that IC entry.
Physical Information: Based on a recessional velocity of 9570 km/sec, a straightforward calculation indicates that PGC 1691585 is about 445 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 430 million light years away at the time the light by which we see it was emitted, about 435 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 0.4 by 0.15 arcmin, the galaxy is about 50 thousand light years across.
SDSS image of region near spiral galaxy PGC 1691585, which was once thought to be IC 4594, and is still sometimes misidentified as that object
Above, a 12 arcmin wide SDSS image centered on PGC 1691585
Below, a 0.6 arcmin wide SDSS image of the galaxy
SDSS image of spiral galaxy PGC 1691585, which was once thought to be IC 4594, and is still sometimes misidentified as that object

IC 4595 (= PGC 57876)
Discovered (Jul 19, 1900) by
DeLisle Stewart
A magnitude 12.0 spiral galaxy (type Sc?) in Triangulum Australe (RA 16 20 43.8, Dec -70 08 33)
Historical Identification: Per Dreyer, IC 4595 (= DeLisle Stewart #429, 1860 RA 16 06 06, NPD 159 48) is "faint, small, extremely extended 55░". The position precesses to RA 16 20 55.2, Dec -70 08 58, only an arcmin to the east of the galaxy listed above, and the description fits, so the identification is certain.
Physical Information: Apparent size 3.0 by 0.4 arcmin.
DSS image of region near spiral galaxy IC 4595
Above, a 12 arcmin wide DSS image centered on IC 4595
Below, a 3 arcmin wide DSS image of the galaxy
DSS image of spiral galaxy IC 4595

IC 4596 (= PGC 57665)
Discovered (Jul 7, 1899) by
DeLisle Stewart
A magnitude 14.0 spiral galaxy (type (R')SB(rs)ab?) in Scorpius (RA 16 16 03.6, Dec -22 37 30)
Historical Identification: Per Dreyer, IC 4596 (= DeLisle Stewart #428, 1860 RA 16 07 44, NPD 112 16) is "faint, small, much extended 40░, much brighter middle and nucleus, probably spiral". The position precesses to RA 16 16 03.1, Dec -22 37 15, less than an arcmin north of the galaxy listed above, and the description fits, so the identification is certain.
Physical Information: Apparent size 1.45 by 0.35 arcmin.
DSS image of region near spiral galaxy IC 4596
Above, a 12 arcmin wide DSS image centered on IC 4596
Below, a 1.5 arcmin wide DSS image of the galaxy
DSS image of spiral galaxy IC 4596

IC 4597 (= PGC 57746)
Discovered (Jul 16, 1903) by
Royal Frost
A magnitude 13.7 spiral galaxy (type Sa? pec) in Scorpius (RA 16 17 39.7, Dec -34 21 57)
Historical Identification: Per Dreyer, IC 4597 (= Frost #1142, 1860 RA 16 08 43, NPD 124 01) has a "brighter middle, magnitude 14". The position precesses to RA 16 17 46.9, Dec -34 22 01, about 1.5 arcmin east of the galaxy listed above, and there is nothing comparable nearby, so the identification seems certain.
Physical Information: Apparent size 1.4 by 1.0 arcmin. Perhaps a starburst galaxy?
DSS image of region near spiral galaxy IC 4597
Above, a 12 arcmin wide DSS image centered on IC 4597
Below, a 2 arcmin wide DSS image of the galaxy
DSS image of spiral galaxy IC 4597

IC 4598 (= PGC 57772)
Discovered (Jul 16, 1903) by
Royal Frost
A magnitude 13.8 spiral galaxy (type Sbc? pec) in Scorpius (RA 16 18 13.2, Dec -31 26 31)
Historical Identification: Per Dreyer, IC 4598 (= Frost #1143, 1860 RA 16 09 22, NPD 121 06) is a "nebulous streak of faint stars, 1 arcmin north-south". The position precesses to RA 16 18 14.0, Dec -31 26 54, on the southeastern outline of the galaxy listed above, and the description fits, so the identification is certain.
Physical Information: Apparent size 1.35 by 0.4 arcmin.
DSS image of region near spiral galaxy IC 4598
Above, a 12 arcmin wide DSS image centered on IC 4598
Below, a 1.8 arcmin wide DSS image of the galaxy
DSS image of spiral galaxy IC 4598

IC 4599
Discovered (Jun 20, 1903) by
Royal Frost
A magnitude 12(?) planetary nebula in Scorpius (RA 16 19 23.2, Dec -42 15 34)
Historical Identification: Per Dreyer, IC 4599 (= Frost #1144, 1860 RA 16 09 38, NPD 131 55) is a "planetary, 15th magnitude". The position precesses to RA 16 19 19.7, Dec -42 15 47, less than an arcmin west of the planetary nebula listed above, and there is nothing similar nearby, so the identification is certain.
Physical Information: Apparent size 0.25 arcmin?
DSS image of region near planetary nebula IC 4599
Above, a 12 arcmin wide DSS image centered on IC 4599
Below, a 0.6 arcmin wide DSS image of the planetary nebula
DSS image of planetary nebula IC 4599
Celestial Atlas
(IC 4500 - 4549) ←     IC Objects: IC 4550 - 4599     → (IC 4600 - 4649)