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Page last updated Oct 8, 2023 (turned bare-bones entry for NGC 6723 into a completed entry)
Page last updated Sep 24, 2023 (Added Caldwell & other IDs for NGC 6744)
Page last updated Aug 23, 2023 (Added Caldwell & other IDs for NGC 6729)
Page last updated Apr 4, 2022
Working NGC 6717
Working NGC 6749, GCL 107
WORKING 6708/9: Still cleaning up mess involving identity of NGC 6708
WORKING 6700: Add/update Steinicke listings/data, check IDs
NGC 6700 (= PGC 62376)
Discovered (Aug 17, 1873) by douard Stephan
A 13th-magnitude spiral galaxy (type SBc?) in Lyra (RA 18 46 04.3, Dec +32 16 46)
Historical Identification: Per Dreyer, NGC 6700 (= GC 5930, Stephan list V (#3), 1860 RA 18 40 50, NPD 57 52.0) is "extremely faint, a little extended, diffuse, irregularly round".
Physical Information: Apparent size 1.4 by 1.0? arcmin
NGC 6701 (= PGC 62314)
Discovered (Aug 6, 1883) by Lewis Swift
A 12th-magnitude spiral galaxy (type SBa?) in Draco (RA 18 43 12.6, Dec +60 39 11)
Historical Identification: Per Dreyer, NGC 6701 (Swift list II (#71), 1860 RA 18 41 27, NPD 29 29.3) is "pretty bright, pretty small, much extended, faint star close to east".
Physical Information: Apparent size 1.5 by 1.3? arcmin
NGC 6702 (= PGC 62395)
Discovered (Sep 8, 1863) by Heinrich d'Arrest
A 12th-magnitude elliptical galaxy (type E2?) in Lyra (RA 18 46 57.6, Dec +45 42 22)
Historical Identification: Per Dreyer, NGC 6702 (= GC 5931, d'Arrest, 1860 RA 18 42 54, NPD 44 26.9) is "pretty faint, small, a little extended".
Physical Information: Apparent size 1.9 by 1.5? arcmin
NGC 6703 (= PGC 62409)
Discovered (Sep 4, 1863) by Heinrich d'Arrest
An 11th-magnitude lenticular galaxy (type E/S0?) in Lyra (RA 18 47 18.9, Dec +45 33 03)
Historical Identification: Per Dreyer, NGC 6703 (= GC 5932, d'Arrest, 1860 RA 18 43 16, NPD 44 36.1) is "bright, small, round, much brighter middle".
Physical Information: Apparent size 2.7 by 2.5? arcmin
NGC 6704 (= OCL 82)
Discovered (Jul 23, 1854) by August Winnecke
Also observed? (date?) by Arthur von Auwers
A 9th-magnitude open cluster (type I3m) in Scutum (RA 18 50 45.8, Dec -05 12 18)
Historical Identification: Per Dreyer, NGC 6704 (= GC 4435, Winnecke, 1860 RA 18 43 20, NPD 95 21.3) is "a cluster, bright, 60 stars of 13th magnitude (Auwers 43)".
Physical Information: Apparent size 6.0? arcmin
NGC 6705 (= M11 = OCL 76), The Wild Duck Cluster
Discovered (1681) by Gottfried Kirch
Also observed (1733) by William Derham
Recorded (1764) by Charles Messier as M11
Also observed (Jul 23, 1827) by John Herschel
A 6th-magnitude open cluster (type I2r) in Scutum (RA 18 51 05.0, Dec -06 16 12)
Historical Identification: Per Dreyer, NGC 6705 (= GC 4437 = JH 2019, Kirch 1681, M 11, 1860 RA 18 43 33, NPD 96 25.9) is "a remarkable object, a cluster, very bright, large, irregularly round, rich, a 9th magnitude star and stars from 11th magnitude".
Discovery Notes: As is the case with many of the objects in Messier's catalog, M11 was first noticed (as a fuzzy patch in the sky) nearly a century earlier, in this case by German astronomer Gottfried Kirch, in 1681. William Derham was probably the first to see that it consisted of a cloud of faint stars, in 1733.
Physical Information: Approximately 5000 light-years distant, M11 is one of the richest and most compact open clusters, with nearly 3000 stars concentrated in a region only twenty light-years across (or from our perspective, about 11 arcmin), many of which are upper Main Sequence blue giants, or more highly evolved yellow and red giants. As a result, an observer in the center of the cluster would see several hundred first magnitude stars scattered around the sky. Given the presence of Main Sequence stars up to spectral class B8, the age of the cluster is estimated at 250 million years, or only about 5% the age of our solar system.
Above, a ? arcmin wide image of NGC 6705 (Image Credit & © Jean-Charles Cuillandre (CFHT), Hawaiian Starlight, CFHT)
NGC 6706 (= PGC 62596)
Discovered (Jun 8, 1836) by John Herschel
Also observed (date?) by DeLisle Stewart
A 13th-magnitude lenticular galaxy (type E/S0?) in Pavo (RA 18 56 51.0, Dec -63 09 59)
Historical Identification: Per Dreyer, NGC 6706 (= GC 4436 = JH 3760, 1860 RA 18 43 37, NPD 153 19.7) is "a nebula. No description".The second IC adds (per DeLisle Stewart) "very faint, very small, considerably extended 120 degrees, stellar nucleus".
Physical Information: Apparent size 1.5 by 0.7? arcmin.
NGC 6707 (= PGC 62563)
Discovered (Jul 8, 1834) by John Herschel
A 13th-magnitude spiral galaxy (type SBc?) in Telescopium (RA 18 55 21.9, Dec -53 49 09)
Historical Identification: Per Dreyer, NGC 6707 (= GC 4438 = JH 3761, 1860 RA 18 44 02, NPD 143 58.8) is "faint, small, very little extended, gradually brighter middle".
Physical Information: Apparent size 2.1 by 1.0? arcmin
NGC 6708 (= PGC 62569)
Discovered (Jun 9, 1836) by John Herschel
A 12th-magnitude spiral galaxy (type Sb?) in Telescopium (RA 18 55 35.6, Dec -53 43 24)
Historical Identification: Per Dreyer, NGC 6708 (= GC 4439 = JH 4021, hon, 1860 RA 18 44 18, NPD 143 53.3) is "pretty faint, small, round, gradually pretty much brighter middle, last of group", the previous entry ( NG 6707) also being a member of the "group".
Discovery Notes: The "hon" in Dreyer's entry refers to a group of observations by Herschel (his 4016 through 4021) which were inadvertently left out of the main part of his catalog and only mentioned in the errata.
Physical Information: Apparent size 1.2 by 0.9? arcmin
NGC 6709 (= OCL 100)
Discovered (Aug 21, 1827) by John Herschel
A 7th-magnitude open cluster (type III2m) in Aquila (RA 18 51 30.0, Dec +10 20 00)
Historical Identification: Per Dreyer, NGC 6709 (= GC 4440 = JH 2020, 1860 RA 18 44 53, NPD 79 49.0) is "a cluster, pretty rich, a little compressed, irregular figure".
Physical Information: Apparent size 15? arcmin
NGC 6710 (= PGC 62482)
Discovered (Aug 3, 1864) by Albert Marth
Discovered (Jul 18, 1871) by douard Stephan
A 13th-magnitude lenticular galaxy (type S0/a?) in Lyra (RA 18 50 34.0, Dec +26 50 19)
Historical Identification: Per Dreyer, NGC 6710 (= GC 5933, Marth #391, Stephan list I (II #25), 1860 RA 18 44 56, NPD 63 19.5) is "very faint, small, round, brighter middle".
Discovery Notes: Although Dreyer credits Stephan's observation to his first list, the object actually appears in his second (as shown in parentheses); so the "I" must be a typographical error. (The objects in Stephan's list II are listed singly and in groups and are not listed by number, so the "#25" is not as useful as the NGC coordinates in identifying the particular object in question, as they agree with Stephan's 1870 RA 18 45 19.95, NPD 63 18 50.1.)
Physical Information: Apparent size 1.7 by 1.0? arcmin
NGC 6711 (= PGC 62456)
Discovered (Aug 5, 1885) by Lewis Swift
A 13th-magnitude spiral galaxy (type SBbc? pec) in Draco (RA 18 49 00.9, Dec +47 39 27)
Historical Identification: Per Dreyer, NGC 6711 (Swift list II (#72), 1860 RA 18 45 04, NPD 42 30.6) is "very faint, pretty small, round, a little brighter middle".
Physical Information: Apparent size 1.1 by 0.9? arcmin
NGC 6712 (= GCL 103 = PGC 2802691)
Possibly discovered (Jul [19?], 1749) by Guillaume Le Gentil
Discovered (Jun 16, 1784) by William Herschel
Also observed (May 27, 1835) by John Herschel
Also observed (Aug 26, 1864) by Heinrich d'Arrest
A magnitude 8.1 globular cluster (type IX) in Scutum (RA 18 53 04.2, Dec -08 42 21)
Historical Identification: Per Dreyer, NGC 6712 (= GC 4441 = JH 3762 = WH I 47, 1860 RA 18 45 26, NPD 98 52.4) is "a globular cluster, pretty bright, very large, irregular, very gradually a little brighter middle, well resolved, clearly consisting of stars." The position precesses to RA 18 53 04.6, Dec -08 42 25, well within the outline of the cluster listed above, the description fits and there is nothing else nearby, so the identification is certain.
Discovery Note: Le Gentil's observation of a nebula which he compares to M22 (which is a globular cluster) was made during observations of the star clouds in Aquila (which lies just to the northeast of "Scutum Sobieski"). However, Le Gentil's description of the position is (as stated by Steinicke) "very vague", so although it is possible that he saw what later became NGC 6712, it is in no way certain.
Physical Information: NGC 6712 is a relatively sparse globular cluster currently located within the inner halo, but its galactic orbit takes it as close as 900 light years to the center of our galaxy on a regular basis (its orbit changes its size and orientation each time, but its minimum and maximum distances from the center remain roughly constant), and it is estimated that it has lost as much as 99% of its mass over the roughly 11 billion years since it is thought to have been formed. If that is correct, its current 1 million stars (though only about 250 thousand Solar masses, since so many of its stars have very low masses) are the paltry remnants of an object originally having 10 to 20 million Solar masses. Being a moderately "young" globular cluster (most of the globulars in the Milky Way were formed even earlier, some even as long ago as 13 billion years, which is only about 700 million years after the formation of the Universe), its stars contain a moderately large number of atoms other than hydrogen and helium, though far less than in stars such as the Sun, which were formed far later. Its professionally measured radius (based on painstaking studies of stars in its region) of about 5 arcmin is about the same as its "tidal" radius, meaning that stars further than that from its center are likely to be torn from it as it passes through the central bulge of the galaxy (most recently, only about 4 or 5 million years ago), as most of them (as stated above) already have been. Given its distance from the Sun of about 25 thousand light years (give or take a couple of thousand, depending on the reference), its actual angular size corresponds to a diameter of about 70 to 75 light years. However, because it lies in a well-populated part of the Milky Way, its outermost stars cannot be distinguished from "field" stars even with the best tools available, and in most images it appears to be only 6 to 8 arcmin in diameter, and its central condensation, which is the most obvious part of the cluster, is even smaller.
Above, a 15 arcmin wide PanSTARRS image centered on NGC 6712 Below, a 7.5 arcmin wide PanSTARRS image of the cluster
Below, a 2.4 arcmin wide HST image of the northeastern part of the central condensation (Image Credit Hubble Legacy Archive, processed and uploaded to Wikimedia Commons by unknown author)
NGC 6713 (= PGC 62487)
Discovered (Aug 3, 1864) by Albert Marth
A 14th-magnitude lenticular galaxy (type S0?) in Lyra (RA 18 50 44.2, Dec +33 57 37)
Historical Identification: Per Dreyer, NGC 6713 (= GC 5934, Marth #392, 1860 RA 18 45 39, NPD 56 12) is "very faint, small, round, brighter middle".
Physical Information: Apparent size 0.4 by 0.3? arcmin
NGC 6714
Recorded (May 27, 1886) by Lewis Swift
A lost or nonexistent object in Draco (RA 18 45 49.0, Dec +66 43 30)
Historical Identification: Per Dreyer, NGC 6714 (Swift list IV (#74), 1860 RA 18 45 46, NPD 23 25.8) is "most extremely faint, pretty small, very difficult, several bright stars to north".
NGC 6715 (= M54 = GCL 104)
Discovered (Jul 24, 1778) by Charles Messier (and listed as M54)
Also observed (Jun 2, 1826) by James Dunlop
Also observed (Jul 31, 1834) by John Herschel
An 8th-magnitude globular cluster (type III) in Sagittarius (RA 18 55 03.3, Dec -30 28 40)
Historical Identification: Per Dreyer, NGC 6715 (= GC 4442 = JH 3763, M 54, Dunlop 624, 1860 RA 18 46 06, NPD 120 38.5) is "a globular cluster, very bright, large, round, gradually then suddenly much brighter middle, well resolved, clearly consisting of stars, stars of 15th magnitude".
Physical Information: M54 is currently about 86 thousand light-years from the Sun, and 60 thousand light-years from the center of the galaxy. However, its galactocentric orbit carries it from nearly 150 thousand light-years from the center of the galaxy (about 400 million years ago) to about 6500 light-years from the center (about 50 million years ago), and despite its currently much higher speed than usual, its outward motion has carried it less than halfway to its next apogalaxion, about 300 million years from now. Because of its roughly 700 million year orbital period, despite its great age it has only orbited the galaxy about a dozen and a half times, so it has suffered far less mass loss than clusters that have passed through the galaxy hundreds of times.
Above, a ? arcmin wide image of NGC 6715 (Image Credit REU Program, AURA, NSF, NOAO) Below, a ? arcmin wide image of the cluster (Image Credit & © Jim Misti, Misti Mountain Observatory; used by permission)
Below, a 3.4 arcmin wide HST image of the cluster (Image Credit ESA, HST, NASA)
NGC 6716 (= OCL 46)
Discovered (Jul 14, 1830) by John Herschel
An 8th-magnitude open cluster (type IV1p) in Sagittarius (RA 18 54 34.0, Dec -19 54 30)
Historical Identification: Per Dreyer, NGC 6716 (= GC 4443 = JH 2021, 1860 RA 18 46 17, NPD 110 04.1) is "a cluster, pretty rich, stars from 9th to 13th magnitude".
Physical Information: Apparent size 10? arcmin
NGC 6717 (includes IC 4802) (= GCL 105 = "PGC 3517747" = ESO 523-SC-014 = Palomar 9)
Discovered (Aug 7, 1784) by William Herschel (later recorded as NGC 6717)
Also observed (Jul 1, 1826) by John Herschel (later recorded as NGC 6717)
Also observed (Jun 30, 1884) by Guillaume Bigourdan (later recorded as NGC 6717 and IC 4802)
Also observed (about 1952) by George Abell (and recorded as Palomar 9)
A magnitude 8.4 globular cluster (type VIII) in Sagittarius (RA 18 55 06.1, Dec -22 42 06)
Historical Identification: Per Dreyer, NGC 6717 (= GC 4444 = JH 2022 = JH 3766 = WH III 143, 1860 RA 18 46 40, NPD 112 52.3) is "faint, small, partially resolved (some stars seen), a cluster plus nebulosity". The position precesses to RA 18 55 07.0, Dec -22 42 00, well within the outline of the cluster, the description fits ane there is nothing comparable nearby, so the identification is certain.
Discovery Notes: Per Corwin, Bigourdan's observation of what became IC 4802 is often misidentified as NGC 6717 itself, but refers to a clump of stars northeast of the nucleus of NGC 6717 (there are also several other misidentifications of IC 4802, but those are discussed at its entry). Corwin also states that Abell noticed NGC 6717 while examining plates taken with the 48-inch Schmidt telescope at Mount Palomar, but didn't realize it was an NGC object, hence its designation as Palomar 9.
Note About PGC Designagtion: As usual for NGC objects, HyperLEDA assigned a PGC designation to this object even though it isn't a galaxy; but a search of the database for that designation returns no result, so it is shown in quotes.
Physical Information: NGC 6717 is currently about 24500 light-years pc from the Sun, and about 7750 light-years from the center of the galaxy. It has an eccentric orbit around the galactic center, which has a considerable rotation of its major axis each time it passes near the center of the galaxy, about every 30 to 35 million years. At perigalaxion it is about 1500 light-years from the center of the galaxy, and at apogalaxion, which it is now approaching, it is a little over 8000 light-years from the center, although it appears that at this apogalaxion it will be a bit closer to the center than usual. The cluster is thought to be about 12 billion years old, so it has moved in and out and around the galaxy several hundred times during its existence, and was undoubtedly stripped of some of its stars during every passage near the center.
The apparent size of the cluster is much smaller than its actual size, partly because it has so many foreground stars between it and us, and partly because its many passages through the central part of the galaxy have made it difficult to see anything but its central condensation. In the HST images below that central condensation appears to be less than an arcmin across, and even in the DSS images it doesn't look much more than a couple of arcmin across; but the actual size of the cluster is thought to be between 5 and 9 arcmin, depending on the confidence of whoever is trying to distinguish cluster stars from foreground and background stars. Given its distance from the Sun, each arcmin corresponds to a little over 7 light-years, so the various apparent sizes noted above correspond to about 7, 15, and 37 to 64 light-years. About half the mass of the cluster is thought to lie within 14 light-years of its center, or the innermost 2 arcmin, which is about the apparent size of the cluster in the DSS images, so the other half is spread over the region between 2 and 7 or so arcmin across.
Above, a 12 arcmin wide DSS image centered on NGC 6717 (νβ Sgr is the magnitude 5.0 star to the north) The circles represent 2 and 7 arcmin diameters, half the mass being inside the inner circle, and half between the two circles Below, a 12 arcmin wide PanSTARRS image of the same region
Below, a ? arcmin wide PanSTARRS image of the cluster
Below, a 1.4 arcmin wide image of the cluster (Image Credit ESA/Hubble and NASA, A. Sarajedini)
Below, a 0.9 arcmin wide image of the cluster (Image Credit as above)
NGC 6718 (= PGC 62688)
Discovered (Jun 23, 1835) by John Herschel
A 13th-magnitude spiral galaxy (type SBb?) in Pavo (RA 19 01 28.9, Dec -66 06 37)
Historical Identification: Per Dreyer, NGC 6718 (= GC 4445 = JH 3764, 1860 RA 18 47 26, NPD 156 17.2) is "very faint, small, round, gradually a little brighter middle, 9th magnitude star to southwest".
Physical Information: Apparent size 1.4 by 0.8? arcmin
NGC 6719 (= PGC 62710)
Discovered (Jun 23, 1835) by John Herschel
A 13th-magnitude spiral galaxy (type Sc?) in Pavo (RA 19 03 07.3, Dec -68 35 16)
Historical Identification: Per Dreyer, NGC 6719 (= GC 4446 = JH 3765, 1860 RA 18 48 03, NPD 158 47.0) is "very faint, pretty large, round, very gradually a very little brighter middle".
Physical Information: Apparent size 1.7 by 0.8? arcmin
NGC 6720 (= M57 = P-K 063+13.1 = "PGC 3517795"), The Ring Nebula
Discovered and recorded as M57 (Jan 31, 1779) by Charles Messier
Discovered (mid-February, 1779) by Antoine Darquier
Also observed (Aug 19, 1828) by John Herschel
A 9th-magnitude planetary nebula in Lyra (RA 18 53 35.1, Dec +33 01 47)
Historical Identification: Per Dreyer, NGC 6720 (= GC 4447 = JH 2023, M 57, Darquier, 1860 RA 18 48 23, NPD 57 08.6) is "a magnificent or otherwise interesting object, an annular nebula, bright, pretty large, considerably extended (in Lyra)".
Discovery Notes: A paper by Messier notes Darquier's "discovery" of the nebula, and as a result it was presumed that Darquier was the original observer; but apparently Messier merely meant that Darquier had also observed the object, as a paper noted in the June 2017 issue of Sky and Telescope shows that according to Darquier's notes, he did not begin to observe Bode's Comet (the great comet of 1779) until February 10, and it was in the course of observing that comet that both Messier an Darquier found the Ring Nebula. So Messier must have been the first to observe the Ring; however, Darquier's note that it looked like a fading planet is what led to such nebulae being called "planetary nebulae".
PGC Designation Note: For purposes of completeness, LEDA assigned a PGC designation to this object, even though it isn't a galaxy; however, a search of the database for that designation returns no result, so it is shown in quotes.
Physical Information: NGC 6720 is about 2000 light years away. Apparent size 3.0 by 2.4? arcmin.
Above, a ? arcmin wide image of NGC 6720 (Image credit H. Bond et al., Hubble Heritage Team (STScI/AURA), NASA)
NGC 6721 (= PGC 62680)
Discovered (Jul 12, 1834) by John Herschel
A 12th-magnitude elliptical galaxy (type E1?) in Pavo (RA 19 00 50.9, Dec -57 45 34)
Historical Identification: Per Dreyer, NGC 6721 (= GC 4448 = JH 3767, 1860 RA 18 48 51, NPD 147 56.8) is "pretty faint, considerably small, round, very much brighter middle".
Physical Information: Apparent size 1.6 by 1.4? arcmin
NGC 6722 (= PGC 62722)
Discovered (Jun 8, 1836) by John Herschel
A 13th-magnitude spiral galaxy (type Sb?) in Pavo (RA 19 03 40.1, Dec -64 53 42)
Historical Identification: Per Dreyer, NGC 6722 (= GC 4449 = JH 3768, 1860 RA 18 49 59, NPD 155 05.4) is "pretty faint, small, extended, gradually a little brighter middle, 2 stars of 8th magnitude to west".
Physical Information: Apparent size 2.9 by 0.4? arcmin
NGC 6723 (= GCL 106 = ESO 396-SC010 = "PGC 3517748")
Discovered (Jun 2, 1826) by James Dunlop
Also observed (Aug 31, 1834) by John Herschel
Also observed (arond 1849) by Christian Peters
A magnitude 7.2 globular cluster (type VII) in Sagittarius (RA 18 59 33.2, Dec -36 37 56)
Historical Identification: Per Dreyer, NGC 6723 (= GC 4450 = JH 3770, Dunlop #573, 1860 RA 18 50 08, NPD 126 48.8) is "a globular cluster, very large, very little extended, very gradually brighter middle, well resolved, clearly consisting of stars, stars from 14th to 16th magnitude." The position precesses to (2000) RA 18 59 33.9, Dec -36 37 43, very slightly northeast of the center of the cluster listed above but well within its boundary, the description fits and there is nothing comparable nearby, so the identification is certain.
Discovery Notes: Per Gottlieb, John Herschel credited Dunlop with the discovery "despite the poor position", implying that Dunlop's description was sufficient to guarantee that he did indeed observe the cluster, but that his position wasn't as good as the one recorded by Herschel (the source of Dreyer's position). Gottlieb also notes that Peters apparently did not have access to Herschel's Cape Catalogue, and independently discovered it at Naples, but did not report the discovery until 1856.
PGC Designation Note: As usual for NGC objects, HyperLEDA assigned a PGC designation to this object, even though it isn't a galaxy; but also as usual in such cases, a search of the database for that designation returns no result, so it is in quotes.
Physical Information: NGC 6723 is about 27,000 ± 300 light-years from the Sun. About half of its roughly 200,000 Solar masses lies within a region 30 to 35 light-years in diameter. In photographs its overall apparent diameter is about 13 arcmin, which at its distance corresonds to about 100 light-years, but even with a fairly large instrument (18 to 24 inches aperture), the visual appearance consists of a bright core about 3 arcmin across, within a fairly obvious region 6 to 8 arcmin wide, and the suggestion of a faint halo essentially indistinguishable from the background stars. Calculations based on its motion indicate that in the current era the cluster has a very eccentric orbit and at the moment is about 8,000 light-years from the center of the galaxy, midway between its perigalaxion of 6,000 light-years and its apogalaxion of 10,000 light-years (these are averages; each of its roughly 50 million year long orbits tends to be different from preceding and following orbits). The cluster's HR diagram suggests that it was formed about 12.5 to 13 billion years ago (about the same time as the oldest clusters in the galaxy). However, unlike most clusters of that age, NGC 6723 has a number of stars with a relatively high metallicity (that is, "significant" amounts of elements other than hydrogen and helium, albeit still only a tiny fraction of the overall mass of the star), suggesting that it had several stages of significant star formation at substantially later dates.
Additional Note: The group of reflection and emission nebulae NGC 6726, 6727, 6729 (= C68) and IC 4812 lie only about half a degree to the southeast of NGC 6723, as shown in the final image below.
Above, a 20 arcmin wide DSS image centered on NGC 6723 Below, a 13 arcmin wide ESO infrared image of the globular cluster (Image Credit ESO/S, Mingast et al.)
Below, a 45 arcmin wide DSS image of the region between the cluster and its southeastern "neighbors" (There is of course no connection between it and them except for being in about the same direction from us)
NGC 6724
Discovered (Sep 5, 1828) by John Herschel
A group of stars in Aquila (RA 18 56 46.0, Dec +10 25 42)
Historical Identification: Per Dreyer, NGC 6724 (= GC 4451 = JH 2024, 1860 RA 18 50 25, NPD 79 49.3) is "a cluster".
Physical Information:
NGC 6725 (= PGC 62692)
Discovered (Jul 8, 1834) by John Herschel
Also observed (date?) by DeLisle Stewart
An 11th-magnitude lenticular galaxy (type S0?) in Telescopium (RA 19 01 56.4, Dec -53 51 51)
Historical Identification: Per Dreyer, NGC 6725 (= GC 4452 = JH 3769, 1860 RA 18 50 26, NPD 144 07.5) is "extremely faint, pretty large, round". The second IC adds (per DeLisle Stewart) "not pretty large, round, but considerably faint, extremely small, stellar nucleus, with straight wisp at 40 degrees".
Physical Information: Apparent size 2.2 by 0.5? arcmin.
NGC 6726
Discovered (Jun 15, 1861) by Julius Schmidt
Discovered (Jul 2, 1864) by Albert Marth
A reflection nebula in Corona Australis (RA 19 01 39.2, Dec -36 53 29)
Historical Identification: Per Dreyer, NGC 6726 (= GC 5935, Marth #393, Schmidt, 1860 RA 18 52 13, NPD 127 04.6) is "a 6th or 7th magnitude star in a faint, pretty large nebulosity".
Physical Information: Apparent size 9.0 by 7.0? arcmin. Paired with NGC 6727.
For now, see the image at NGC 6729
NGC 6727
Discovered (Jun 15, 1861) by Julius Schmidt
Discovered (Jul 2, 1864) by Albert Marth
A reflection nebula in Corona Australis (RA 19 01 42.2, Dec -36 52 35)
Historical Identification: Per Dreyer, NGC 6727 (= GC 5936, Marth #394, Schmidt, 1860 RA 18 52 15, NPD 127 03.8) is "an 8th magnitude star in a faint, pretty large nebulosity".
Physical Information: Apparent size 80? arcmin. Paired with NGC 6726.
For now, see the image at NGC 6729
NGC 6728
Discovered (Jun 16, 1784) by William Herschel
A group of stars in Scutum (RA 18 57 31.4, Dec -08 57 56)
Historical Identification: Per Dreyer, NGC 6728 (= GC 4453 = WH VIII 13, 1860 RA 18 52 21, NPD 99 07.6) is "a cluster, very large, poor".
Physical Information: Apparent size 18? arcmin
NGC 6729, the R Coronae Australis Nebula
(= C68 = PGC 3084736 = ESO 396-N*015)
Discovered (Jun 15, 1861) by Julius Schmidt
Discovered (Jul 2, 1864) by Albert Marth
An emission and reflection nebula in Corona Australis (RA 19 01 55.3, Dec -36 57 28)
Historical Identification: Per Dreyer, NGC 6729 (= GC 5937, Marth #395, Schmidt, 1860 RA 18 52 28, NPD 127 08.5) is "a variable star (11th magnitude and fainter) with nebulosity, a very remarkable object".
Physical Information: Apparent size 25 by 20? arcmin. In same region as reflection nebulae NGC 6726, NGC 6727, and IC 4812.
Above, a 30 arcmin wide ESO image of the region near NGC 6729; the nebula is the small bright region to the right of the label. The large bluish reflection nebulae surrounding the pair of stars to the northwest are emission nebulae NGC 6726 and 6727. The emission nebula surrounding the double star to the southwest is IC 4812. Brownish regions are dust clouds that are relatively 'thin', and only partially block the light from objects behind them, while the dark regions nearly devoid of stars are 'dense' clouds of dust that completely block our view of more distant objects. (Image Credit above & below ESO) Below, a 10 arcmin ESO image of the nebula and bright and dark clouds to its southwest
Below, a 7 arcmin wide ESO image of star formation in the regions to the southwest (Image Credit ESO/Sergey Stepanenko)
NGC 6730 (= PGC 62796)
Discovered (Jul 23, 1835) by John Herschel
An 11th-magnitude elliptical galaxy (type E1?) in Pavo (RA 19 07 33.6, Dec -68 54 44)
Historical Identification: Per Dreyer, NGC 6730 (= GC 4454 = JH 3771, 1860 RA 18 52 32, NPD 159 06.8) is "very faint, small, round, pretty much brighter middle, 7th or 8th magnitude star to northeast".
Physical Information: Apparent size 1.8 by 1.5? arcmin. Only 1.5 arcmin southwest of 7th magnitude SAO 254465.
Above, a 12 arcmin wide DSS image centered on NGC 6730 Below, a 2.4 arcmin wide DSS image of the galaxy
NGC 6731
Discovered (1886) by Gerhard Lohse
A group of stars in Lyra (RA 18 57 13.5, Dec +43 04 38)
Historical Identification: Per Dreyer, NGC 6731 (J. G. Lohse, 1860 RA 18 52 34, NPD 47 07.1) is "very faint".
Physical Information:
NGC 6732 (= PGC 62586)
Discovered (Oct 16, 1886) by Lewis Swift
Also observed (Sep 8, 1888) by Guillaume Bigourdan
Also observed (date?) by Herbert Howe
A 14th-magnitude elliptical galaxy (type E4?) in Draco (RA 18 56 24.1, Dec +52 22 39)
Historical Identification: Per Dreyer, NGC 6732 (Swift list V (#87), 1860 RA 18 52 50, NPD 37 48.0) is "pretty bright, very small, round, faint star to north". The second IC lists a corrected RA (per Howe and Bigourdan) of 18 53 09.
Physical Information: Apparent size 1.2 by 0.7? arcmin.
Above, a 12 arcmin wide DSS image centered on NGC 6732 Below, a 2.4 arcmin wide DSS image of the galaxy, also showing PGC 2413402
PGC 2413402
Not an NGC object but listed here since an optical double with NGC 6732
A 15th-magnitude compact galaxy (type C??) in Draco (RA 18 56 26.2, Dec +52 22 38)
Physical Information: Apparent size 0.1 by 0.1? arcmin; nothing else available. Probably an optical double with NGC 6732 (which see for images), rather than a physical pairing. Given the poor quality of available images possibly a foreground star or stars (as suggested by NED).
NGC 6733 (= PGC 62770)
Discovered (Aug 8, 1834) by John Herschel
A 12th-magnitude lenticular galaxy (type SB0?) in Pavo (RA 19 06 10.7, Dec -62 11 48)
Historical Identification: Per Dreyer, NGC 6733 (= GC 4455 = JH 3772, 1860 RA 18 53 15, NPD 152 23.6) is "most extremely faint, very gradually a little brighter middle, very difficult".
Physical Information: Apparent size 1.8 by 1.2? arcmin
NGC 6734 (= PGC 62786)
Discovered (Jun 8, 1836) by John Herschel
A 13th-magnitude lenticular galaxy (type E/S0?) in Pavo (RA 19 07 14.4, Dec -65 27 39)
Historical Identification: Per Dreyer, NGC 6734 (= GC 4456 = JH 3773, 1860 RA 18 53 29, NPD 155 39.7) is "very faint, small, round, gradually a little brighter middle, western of 2", the other being NGC 6736.
Physical Information: Apparent size 1.3 by 1.1? arcmin
NGC 6735
Discovered (Jul 18, 1827) by John Herschel
A star group in Aquila (RA 19 00 45.3, Dec -00 27 21)
Historical Identification: Per Dreyer, NGC 6735 (= GC 4457 = JH 2025, 1860 RA 18 53 33, NPD 90 39.1) is "a cluster, very large, poor, stars from 12th magnitude".
Physical Information: Apparent size 8.0? arcmin. Near 7th-magnitude SAO 142915.
NGC 6736 (= PGC 62792)
Discovered (Jun 8, 1836) by John Herschel
A 13th-magnitude elliptical galaxy (type E2?) in Pavo (RA 19 07 29.3, Dec -65 25 43)
Historical Identification: Per Dreyer, NGC 6736 (= GC 4458 = JH 3774, 1860 RA 18 53 45, NPD 155 38.2) is "extremely faint, small, round, gradually a little brighter middle, eastern of 2", the other being NGC 6734.
Physical Information: Apparent size 1.1 by 0.9? arcmin
NGC 6737
Discovered (Jul 14, 1830) by John Herschel
A group of stars in Sagittarius (RA 19 02 10.0, Dec -18 32 48)
Historical Identification: Per Dreyer, NGC 6737 (= GC 4459 = JH 2026, 1860 RA 18 53 59, NPD 108 44.1) is "a cluster, pretty large, pretty rich, round, stars from 12th to 15th magnitude".
Physical Information:
NGC 6738 (= OCL 101)
Discovered (Jul 29, 1829) by John Herschel
An 8th-magnitude open cluster in Aquila (RA 19 01 20.0, Dec +11 36 54)
Historical Identification: Per Dreyer, NGC 6738 (= GC 4460 = JH 2027, 1860 RA 18 54 50, NPD 78 35.3) is "a cluster, poor, a little compressed".
Physical Information: Apparent size 15? arcmin
NGC 6739 (= PGC 62799)
Discovered (Aug 7, 1834) by John Herschel
A 12th-magnitude lenticular galaxy (type S0?) in Pavo (RA 19 07 48.7, Dec -61 22 03)
Historical Identification: Per Dreyer, NGC 6739 (= GC 4461 = JH 3775, 1860 RA 18 55 07, NPD 151 34.4) is "considerably faint, very small, considerably extended, pretty suddenly brighter middle, 3 stars to west".
Physical Information: Apparent size 2.4 by 0.9? arcmin
NGC 6740 (= PGC 62675)
Discovered (Jun 28, 1864) by Albert Marth
A 14th-magnitude spiral galaxy (type Sb?) in Lyra (RA 19 00 50.5, Dec +28 46 16)
Historical Identification: Per Dreyer, NGC 6740 (= GC 5938, Marth #396, 1860 RA 18 55 20, NPD 61 25) is "most extremely faint, small".
Physical Information: Apparent size 0.9 by 0.8? arcmin
NGC 6741 (= P-K 033-02.1 = "PGC 3517796")
Discovered (Aug 19, 1882) by Edward Pickering
A 12th-magnitude planetary nebula in Aquila (RA 19 02 37.0, Dec -00 26 56)
Historical Identification: Per Dreyer, NGC 6741 (Pickering (HN 50), 1860 RA 18 55 25, NPD 90 38) is "a planetary nebular, stellar".
PGC Designation Note: For purposes of completeness, LEDA assigned a PGC designation to this object, even though it isn't a galaxy; however, a search of the database for that designation returns no result, so it is shown in quotes.
Physical Information: Apparent size 0.13? arcmin
WORKING HERE: remove artifact in DSS image
NGC 6742 (= Abell 50)
Discovered (Jul 8, 1788) by William Herschel
Also observed (Sep 24, 1862) by Heinrich d'Arrest
A 13th-magnitude planetary nebula in Draco (RA 18 59 19.8, Dec +48 27 59)
Historical Identification: Per Dreyer, NGC 6742 (= GC 4462 = WH III 742, d'Arrest, 1860 RA 18 55 32, NPD 41 45.2) is "very faint, stellar".
Physical Information: NGC 6742 is probably about 13 thousand light years away. If so, the nebula's apparent size of 33 arcsec corresponds to about 0.9 light years. The 20th-magnitude central star has a temperature of about 100 thousand Kelvins, and because of its high temperature is about 50 times as bright as the Sun despite having collapsed to a white dwarf about the size of the Earth.
Above, a 12 arcmin wide NOAO/DSS composite image centered on NGC 6742 Below, a 2.4 arcmin wide image of the nebula (Image Credit above & below Adam Block/NOAO/AURA/NSF)
NGC 6743
Discovered (Jul 6, 1828) by John Herschel
A group of stars in Lyra (RA 19 01 26.7, Dec +29 17 24)
Historical Identification: Per Dreyer, NGC 6743 (= GC 4463 = JH 2028, 1860 RA 18 55 58, NPD 60 55.6) is "a cluster, pretty large, poor, stars from 11th to 12th magnitude".
Physical Information: Apparent size 8.0? arcmin
NGC 6744
(= C101 = ESO 104-042 = PGC 62836)
Discovered (Jun 30, 1826) by James Dunlop
Also observed (Jun 20, 1835) by John Herschel
A magnitude 9.2 spiral galaxy (type SBbc?) in Pavo (RA 19 09 46.1, Dec -63 51 27)
Historical Identification: Per Dreyer, NGC 6744 (= GC 4464 = JH 3776, Dunlop #262, 1860 RA 18 56 27, NPD 154 04.0) is "considerably bright, considerably large, round, very gradually then suddenly very much brighter middle, mottled but not resolved." The position precesses to (2000) RA 19 09 45.8, Dec -63 51 17, barely northwest of the center of the galaxy listed above and within the outline of its central bar, the description fits and there is nothing comparable nearby, so the identification is certain.
Physical Information: Apparent size 20.1 by 12.9? arcmin. NGC 6744 is about 30 million light years away. Its appearance is thought to be nearly identical to our own galaxy, save for the fact that it is about twice as large, and therefore probably about ten times as massive. (Note: the stated size of the galaxy includes some very faint outer arms. In the Observatorio Antilhue image immediately below the faint tracery of the northernmost arm extends nearly to the top of the image, then curves around past the faint irregular galaxy ( PGC 62815) to the northwest of the spiral.)
Above, a nearly 20 arcmin wide image of NGC 6744 (Credit & © for image above Daniel Verschatse, Observatorio Antilhue; used by permission) (The image credit link shown above is broken, but will be replaced with its present location ASAP) Below, a ? arcmin wide multi-spectral image of the galaxy emphasizes its emission nebulae (Image Credit ESO; the mis-registration of component images is not uncommon in such composites)
PGC 62815 (= "NGC 6744A")
Not an NGC object, but listed here since sometimes called NGC 6744A
A 15th-magnitude irregular galaxy (type IBm?) in Pavo (RA 19 08 43.7, Dec -63 43 48)
Physical Information: Apparent size 1.8 by 0.7? arcmin.
Above, a 2.4 arcmin wide image centered on PGC 62815 (Credit & © for images above & below Daniel Verschatse, Observatorio Antilhue; used by permission) Below, a 12 arcmin wide image showing the galaxy's position relative to NGC 6744
NGC 6745 (= PGC 62691 (= PGC 2170240) + PGC 200362)
Discovered (Jul 24, 1879) by douard Stephan
A 13th-magnitude spiral galaxy (type S??) in Lyra ( RA 19 01 41.7, Dec +40 44 37)
Companion PGC 200361 = a 15th-magnitude spiral galaxy (type Sm?) at RA 19 01 41.9, Dec +40 45 35
Historical Identification: Per Dreyer, NGC 6745 (Stephan list X (#38), 1860 RA 18 57 07, NPD 49 27.3) is "very faint, a little extended north-south". The position precesses to (2000) RA 19 01 42.0, Dec +40 44 41, dead center on the galaxy, and the description fits, so the identification is certain.
Physical Information: NGC 6745 collided with its northern "companion" (PGC 200361) about ten million years ago (this is determined by the ages of the stars created by the collision; some of the brighter ones are already dying, and their properties correspond to stars with lifetimes of about ten million years). Dynamical studies indicate that the smaller galaxy approached the larger one from the lower right, swung around it and collided with its tidally distorted outline. In the process, clouds of gas and dust in each galaxy slammed into similar clouds in the other, resulting in shock-wave formation of large numbers of stars, most notably large numbers of hot, bright stars which make up the knots of bright stars on the left and upper side of NGC 6745 (the collisional region being so bright that it has its own listing, as PGC 200362). Despite their collision the two galaxies are unlikely to merge, as the smaller one appears to be moving away from the larger one at close to a thousand km/sec (data are scant, but there is an NED reference to the difference in velocity). Based on its recessional velocity of 4545 km/sec, NGC 6745 is about 200 million light years away. Given that and its apparent size of 1.4 by 0.5 arcmin (counting the extension referred to as PGC 200362), it is about 85 thousand light years across. Its companion (PGC 200361) is about 0.3 by 0.2 arcmin, which corresponds to about 20 thousand light years.
Above, a 12 arcmin wide SDSS image centered on NGC 6745 and PGC objects 200361 and 200362 Below, a 2.4 arcmin wide SDSS image of the interacting galaxy pair
Below, a ? arcmin wide image of NGC 6745 and part of PGC 200361 (Image Credit NASA and The Hubble Heritage Team (STScI/AURA), Roger Lynds (KPNO/NOAO), Hubblesite)
NGC 6746 (= PGC 62852)
Discovered (Aug 11, 1836) by John Herschel
A 13th-magnitude lenticular galaxy (type E/S0?) in Pavo (RA 19 10 22.3, Dec -61 58 06)
Historical Identification: Per Dreyer, NGC 6746 (= GC 4465 = JH 3777, 1860 RA 18 57 32, NPD 152 10.6) is "extremely faint, considerably small, round, gradually a little brighter middle".
Physical Information: Apparent size 1.4 by 0.9? arcmin
NGC 6747 (= PGC 62564)
Discovered (Oct 31, 1886) by Lewis Swift
A 14th-magnitude elliptical galaxy (type E2?) in Draco (RA 18 55 21.5, Dec +72 46 20)
Historical Identification: Per Dreyer, NGC 6747 (Swift list V (#88), 1860 RA 18 57 42, NPD 17 23.5) is "most extremely faint, very difficult, pretty bright star to southeast".
Physical Information: Apparent size 0.5 by 0.4? arcmin
NGC 6748 (= NGC 6751 = P-K 029-05.1 = "PGC 3517798")
Discovered (Jul 20, 1863) by Albert Marth (and later listed as NGC 6751)
Discovered but misrecorded (Jul 17, 1871) by douard Stephan (and later listed as NGC 6748)
Rediscovered (Aug 3, 1881) by douard Stephan (and later listed as NGC 6751)
A 12th-magnitude planetary nebula in Aquila (RA 19 05 55.5, Dec -05 59 30)
Historical Identification: Per Dreyer, NGC 6748 (= GC 5939, Stephan list II (#26), 1860 RA 18 57 51, NPD 68 35.8) is "pretty bright, very small, brighter middle".
Discovery Notes: Though NGC 6748 was thought to be irretrievably lost until recently, Esmiol's 1916 update of Stephan's observations to the equinox of 1900 showed that his observation of Jul 17, 1871 was a misrecorded observation of NGC 6751 (which he accurately recorded on Aug 3, 1881), so it was just bad luck that the duplicate listing went unrecognized for so long.
PGC Designation Note: LEDA lists NGC 6748 as a double star and for purposes of completeness, assigns it a PGC designation of "PGC 5067483"; however, a search of the database for that designation does not return a result, so it would be shown in quotes even if correct. However, the recent discovery that this is actually a duplicate observation of NGC 6751 means that the equally useless PGC designation assigned by LEDA to NGC 6751 is the one shown in quotes in the title for this entry.
NGC 6749 (not = GCL 107)
Discovered (Jul 15, 1827) by John Herschel
Discovered (Aug 24, 1891) by Guillaume Bigourdan
A loose scattering of (field?) stars in Aquila near RA 19 05 02.0, Dec +01 47 12
Historical (Mis)identification: Per Dreyer, NGC 6749 (= GC 4466 = JH 2029, 1860 RA 18 57 57, NPD 88 25.2) is "a cluster, large, a little compressed, stars large and small". The position precesses to (2000) RA 19 05 02.0, Dec +01 47 12, but there is nothing there. There is a globular cluster about 8 arcmin to the north-northeast, which is almost universally (mis)identified as NGC 6749, but that object not only has the wrong position but also fails to fit Herschel's description, as described in detail in the following paragraph.
Herschel wrote "A cluster of loose small (faint) stars of various magnitudes; fills the field." This does not in any way describe GCL 107, which per Steve Gottlieb is so small that (based on his own observations) no visual observer of the 1800's could possibly see it resolved into stars, and it would certainly not "fill the field." Bigourdan's examination of the region specified by Herschel as JH 2029 and by Dreyer as NGC 6749 translates (per Corwin) as "Extended region, slightly rich in stars. but which offers nothing remarkable." As seen in the image below, there is a scattering of stars of slightly greater brightness than the multitude of faint background stars which extends for several arcmin in all directions (though particularly toward the northeast) from Herschel's position; but (as noted by Corwin) odds are that they are just randomly scattered stars, and not a cluster of any sort. Unfortunately, GCL 107 has been misidentified as NGC 6749 for so long that it will probably always be misidentified as the NGC object, hence this warning and the entry below.
Above, a 12 arcmin wide ? image centered on the NGC position for NGC 6749, which is not GCL 107
GCL 107 (not = NGC 6749)
(= "PGC 3517749" = OCL 91 = Berkeley 42)
Not an NGC object but listed here because almost universally misidentified as NGC 6749
A magnitude 10.8 globular cluster (type XII?) in Aquila (RA 19 05 15.9, Dec +01 54 07)
Historical Misidentification: As noted in the entry for NGC 6749, neither Herschel's position nor description fits this globular cluster. However, since the globular is the only thing of note anywhere near Herschel's position, it has been almost universally misidentified as the NGC object for decades, so this entry and the one for NGC 6749 serve as a warning about that.
Note About PGC Designation: As is the case for most NGC objects, HyperLEDA assigned this a PGC designation even though it isn't a galaxy; but as is also the case in most such situations a search of the database for that designation returns no result, so it is shown in quotes.
Physical Information: The cluster is about 25 to 26 thousand light years from the Sun; given that and its apparent size of about 5.5 arcmin (both numbers taken from Corwin's globular cluster database), it is about 40 light years across. Compared to other globulars, GCL 107 is very sparsely populated; as a result, it is also cataloged as a rich open cluster. Based on the most detailed discussion I can find it is almost certainly an ancient "halo" globular cluster currently diving toward the center of our galaxy, and already stripped of most of its stars by many prior passages through the nucleus of the galaxy, whence its very loose structure, and not a far younger open cluster.
Above, a 12 arcmin wide DSS image centered on GCL 107, which is not NGC 6749 Below, an 8 arcmin wide DSS image of the cluster
Below, an 8 arcmin wide PanSTARRS image of the cluster (needs solarization cleanup)
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