QuickLinks: 6600, 6601, 6602, 6603, 6604, 6605, 6606, 6607, 6608, 6609, 6610, 6611, 6612, 6613, 6614, 6615, 6616, 6617, 6618, 6619, 6620, 6621, 6622, 6623, 6624, 6625, 6626, 6627, 6628, 6629, 6630, 6631, 6632, 6633, 6634, 6635, 6636, 6637, 6638, 6639, 6640, 6641, 6642, 6643, 6644, 6645, 6646, 6647, 6648, 6649
Page last updated Aug 6, 2011
WORKING: Add positions/physical data (per Steinicke)
NGC 6600 (= NGC 6599)
Discovered (Jun 6, 1864) by Albert Marth (374) (and later listed as NGC 6600) Discovered (Jul 27, 1880) by Édouard Stephan (and later listed as NGC 6599) A 13th-magnitude lenticular galaxy (type S0) in Hercules (RA 18 15 42.9, Dec +24 54 47)
NGC 6601
Discovered (Aug 4, 1883) by Lewis Swift (1-90)
The second IC lists a corrected RA (per Bigourdan) of 18 10 48.
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NGC 6602
Discovered (Jul 1, 1886) by Guillaume Bigourdan (II-83)
NGC 6603
Discovered (Jul 15, 1830) by John Herschel
NGC 6604
Discovered (Jul 15, 1784) by William Herschel
NGC 6605
Discovered (Jul 31, 1826) by John Herschel
NGC 6606
Discovered (Aug 8, 1883) by Édouard Stephan (13b-88)
NGC 6607
Discovered (Aug 4, 1883) by Lewis Swift (1-91)
The second IC states "Not found by Howe (3 nights)".
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NGC 6608
Discovered (Aug 4, 1883) by Lewis Swift (1-92)
The second IC states "Not found by Howe (2 nights); = 6609?".
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NGC 6609
Discovered (Aug 4, 1883) by Lewis Swift (1-93)
In a note about NGC 6608, the second IC states "Not found by Howe (2 nights); = 6609?".
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NGC 6610 (= NGC 6574)
Discovered (Jul 9, 1863) by Albert Marth (and later listed as NGC 6574)
Discovered (Jul 13, 1876) by Édouard Stephan (7-21) (and later listed as NGC 6610) A 12th-magnitude barred spiral galaxy (type SBbc) in Hercules (RA 18 11 51.2, Dec +14 58 54)
NGC 6611 (= M16) -- an open cluster in The Eagle Nebula
Discovered (1745) by Philippe de Chéseaux
Observed (Jun 3, 1764) by Charles Messier and listed as M16
Rediscovered (1783) by William Herschel
Listed by Dreyer as discovered (1836) by John Herschel
A 6th-magnitude open cluster associated with IC 4703 in Serpens (RA 18 18 45.0, Dec -13 47 54)
Dreyer's precessed position is a few seconds east and 1.5 arcmin north of the "standard" position, but in comparison to the size of the cluster the discrepancy is minor; so there is no doubt of the identification. Although de Chéseaux discovered the cluster in the 1740's, his only publication of his discoveries was a report to the French Academy of Sciences which was more or less forgotten until Guillaume Bigourdan published a note about de Cheseaux in 1892; so when Dreyer published the New General Catalog, which was primarily an updating and expansion of John Herschel's General Catalog, he credited John Herschel as the discoverer. Why he didn't credit Messier, or John's father William Herschel, is not obvious at this writing. (Far more to follow, but the following is interesting...) The Eagle Nebula and the young star cluster associated with it are about 7000 light years away, meaning we see them as they were 7000 years ago. But up to the left of the brightest part of the nebula, where the star cluster is centered, is a violently expanding cloud of gas caused by a supernova which took place a few thousand years beforehand. Estimates are that six thousand years ago, high-velocity supernova gases slammed into, compressed and simultaneously tore apart the so-called "Pillars of Creation" near the center of the nebula (though we won't see that until a millennium from now). In the process, most of the clouds of gas and dust visible here would be torn apart, but some of the denser nodules hidden inside the Pillars would be violently compressed, to quickly form bright new stars. In fact, in such regions close to half the bright stars formed are the result of such events, and for lower mass stars like our Sun, compression by expanding gases is almost always the cause of their formation. |
 Above, a view of the region (T.A.Rector (NRAO/AUI/NSF and NOAO/AURA/NSF) and B.A.Wolpa (AURA/NSF), NOAO) Click here for a much larger view of the image above Below, a closer (cropped) view of the image above (Image credits as above)
 Below, a HST view of the "Pillars of Creation", a star-forming region now long-gone (Image Credits: J. Hester, P. Scowen (ASU), NASA, HST)

NGC 6612
Discovered (1886) by Lewis Swift (6-?)
NGC 6613 (= M18)
Discovered (Jun 3, 1764) by Charles Messier
A 7th-magnitude open cluster in Sagittarius (RA 18 19 58.0, Dec -17 06 06)
M18 is a loose collection of about 20 stars, spread over a region about 15 to 20 light-years in diameter, four to six thousand light-years from the Sun. Its hottest, brightest members are of the relatively 'early' spectral type B3, which means it is probably about 30 million years old. |
 Above, an NOAO view of M18 (Image Credit: Hillary Mathis, REU program, AURA, NSF, NOAO)
NGC 6614
Discovered (Jun 20, 1835) by John Herschel
NGC 6615
Discovered (Jul 9, 1863) by Albert Marth (375)
NGC 6616
Discovered (Jul 14, 1885) by Lewis Swift (2-64)
The second IC adds (per Howe) "RA is 18 11 47, the 2 stars are 9th to 10th magnitude, one 2 seconds west and 0.6 arcmin south".
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NGC 6617
Discovered (Jun 14, 1885) by Lewis Swift (1-94)
NGC 6618 (= M17, the Swan, or Omega Nebula)
Discovered (1745) by Phillipe de Cheseaux
Recorded (Jun 3, 1764) by Charles Messier and listed as M17
An emission nebula and open cluster in Sagittarius (RA 18 20 47.0, Dec -16 10 18)
Dreyer's precessed position is less than 0.2 arcmin south of the standard position, so the identification is certain. Although de Chéseaux discovered the cluster in the 1740's, his only publication of his discoveries was a report to the French Academy of Sciences which was more or less forgotten until Guillaume Bigourdan published a note about de Cheseaux in 1892; so Messier's discovery was presumably independent. The brighter parts of the nebula appear somewhat like a bird floating on a body of water, hence the "Swan". The brightest part of the nebula extend over 15 light years, but fainter clumps of gas cover 40 or more light years. About three dozen young stars are hidden within the gas and dust of the nebula, which has nearly a thousand solar masses of gas thinly spread over its volume. The Swan is about 5700 light years from the Sun.
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 Above, a view of the Swan (Adam Block/NOAO/AURA/NSF/NOAO) Below, a multi-spectral image of the Swan reveals more detail (Image Credits: ESO)
 Below, a wider view of the nebula (Image Credits and ©: Jim Misti, Misti Mountain Observatory; used by permission)
 Below, a wider multi-spectral image reveals features hidden in visible light (Image Credits: ESO/INAF-VST/OmegaCAM. Acknowledgement: OmegaCen/Astro-WISE/Kapteyn Institute)

NGC 6619
Discovered (Jun 6, 1864) by Albert Marth (376)
NGC 6620
Discovered (Sep 3, 1880) by Edward Pickering (HN 43)
NGC 6621 (with NGC 6622 = Arp 81)
Discovered (Jun 2, 1885) by Edward Swift (1-95)
 Above, a 2.4 arcmin wide view of NGC 6621 and 6622, also known as Arp 81 Below, a HST view of the pair (slightly rotated to allow for greater detail) (Image Credits: NASA, ESA, Hubble Heritage (STScI/AURA)-ESA, W. Keel (Univ. Alabama, Tuscaloosa))
 Below, a 12 arcmin wide region centered on the pair
NGC 6622 (with NGC 6621 = Arp 81)
Discovered (Jun 2, 1885) by Lewis Swift (1-96)
NGC 6623
Discovered (Jun 6, 1864) by Albert Marth (377)
NGC 6624
Discovered (Jun 24, 1784) by William Herschel
NGC 6625
Discovered (Jul 31, 1826) by John Herschel
NGC 6626 (= M28)
Discovered (Jul 27, 1764) by Charles Messier
A 7th-magnitude globular cluster in Sagittarius (RA 18 24 32.9, Dec -24 52 10)
About 80 light years across, and 18 thousand light years away
 Above, a closeup of M28 (Image Credits: AURA, NSF, NOAO) Below, a slightly wider view (Image Credits and ©: Jim Misti, Misti Mountain Observatory; used by permission)

NGC 6627
Discovered (Jul 13, 1863) by Albert Marth (378)
NGC 6628
Discovered (Jun 6, 1864) by Albert Marth (379)
NGC 6629
Discovered (Aug 7, 1784) by William Herschel
An 11th-magnitude planetary nebula in Sagittarius (RA 18 25 42.4, Dec -23 12 08)
Apparent size 0.4 by 0.35 arcmin. |
 Above, a 2.4 arcmin wide view of NGC 6629 (a composite of HST and DSS images) Below, a closeup of the Hubble Legacy Archive image
 Below, a 12 arcmin wide region centered on the planetary nebula (as above, a composite image)

NGC 6630
Discovered (Jun 8, 1836) by John Herschel
NGC 6631
Discovered (Jul 12, 1836) by John Herschel
NGC 6632
Discovered (Jun 24, 1864) by Albert Marth (380)
NGC 6633 (= OCL 90)
Discovered (1745) by Phillipe de Cheseaux
Discovered (Jul 31, 1783) by Caroline Herschel
A 5th-magnitude open cluster in Ophiuchus (RA 18 27 15.1, Dec +06 30 30)
Per Dreyer, NGC 6633 (= John Herschel's GC 4410, Caroline Herschel, 1860 RA 18 20 43, NPD 83 31.3) is a "cluster, a little compressed, large star". Although de Chéseaux discovered the cluster in the 1740's, his only publication of his discoveries was a report to the French Academy of Sciences which was more or less forgotten until Guillaume Bigourdan published a note about de Cheseaux in 1892; so Dreyer had no way of knowing that Caroline Herschel was not the first to see the object. The position precesses to RA 18 27 32.0, Dec +06 33 37, about 3 arcmin northeast of the position listed above, but well within the boundary of the cluster, and "large star" almost certainly refers to 6th-magnitude HD 170200, which is on the southeast periphery of the field; so the identification is certain. The cluster contains a couple of dozen relatively bright stars scattered across an irregularly shaped 20 to 30 arcmin wide field, the brightest being about magnitude 7 1/2. At the cluster's estimated distance of a thousand light years, its apparent size corresponds to about 8 light years. Based on the spectral types of its Main Sequence stars, NGC 6633's age is estimated at six to seven hundred million years. |
 Above, a half degree wide region centered on NGC 6633 Below, a 45 arcmin wide region centered on the cluster

NGC 6634
Discovered (1751) by Nicolas Lacaille
A group of stars in Sagittarius (RA 18 29 55.3, Dec -33 30 40)
Per Dreyer, NGC 6634 (= Lacaille list I #11, 1860 RA 18 20 45, NPD 123 30.5) is a "nebula, without stars". The object is now identified as a group of stars without nebulosity, showing the difficulty of determining the nature of faint fuzzy objects with visual observations through a small telescope. (Steinicke notes "not M69". This refers to the fact that Messier was looking for Lacaille's nebula when he found M69, and thought he had rediscovered the same object, as M69 looks nebular in a small telescope; but they are not the same object at all.) The position precesses to RA 18 29 58.2, Dec -33 25 20, about 5 arcmin north of the listed position; but there is nothing else nearby, so the identification is reasonably certain. NGC 6634 consists of less than half a dozen stars, ranging from 7th to 9th magnitude, and would hardly seem worth noting, if its true nature had been more readily apparent to Lacaille. |
 Above, a 15 arcmin wide region centered on NGC 6634
NGC 6635
Discovered (Jul 9, 1863) by Albert Marth (381)
NGC 6636
Discovered (Jul 23, 1884) by Lewis Swift (4-68)
NGC 6637 (= M69)
Discovered (Aug 31, 1780) by Charles Messier
An 8th-magnitude globular cluster in Sagittarius (RA 18 31 23.2, Dec -32 20 51)
M69 is about 30 thousand light years away. Given that, its apparent size corresponds to about 50 light years. It is said to be one of the most metal-rich of all globular clusters, suggesting a slightly younger age than is typical for such ancient objects; but its stars still have far fewer "metal" atoms (that is, atoms other than hydrogen and helium) than much younger stars like our Sun. |
 Above, a roughly 6 arcmin wide view of M69 (Image Credits: REU program, AURA, NSF, NOAO) Below, a closeup of the cluster's central 3.5 arcmin (Image Credits: ESA/HST (Wikisky cutout))
 Below, a 12 arcmin wide region centered on the cluster (Composite of the NOAO image above, and a DSS image)

NGC 6638
Discovered (Jul 12, 1784) by William Herschel
NGC 6639
Discovered (Jul 31, 1826) by John Herschel
NGC 6640
Discovered (Aug 21, 1884) by Édouard Stephan (13b-89)
NGC 6641
Discovered (Aug 9, 1866) by Truman Safford (47)
NGC 6642
Discovered (Aug 7, 1784) by William Herschel
NGC 6643
Discovered (1858) by Eduard Schönfeld (BD +74 766)
NGC 6644
Discovered (Jul 13, 1880) by Edward Pickering
NGC 6645
Discovered (Jun 27, 1786) by William Herschel
NGC 6646
Discovered (Jun 26, 1802) by William Herschel
NGC 6647
Discovered (Jun 18, 1784) by William Herschel
NGC 6648
Recorded (1825) by Wilhelm Struve (7)
A pair of stars in Draco (RA 18 25 37.4, Dec +64 58 33)
NGC 6649 (= OCL 66)
Discovered (May 27, 1835) by John Herschel
A 9th-magnitude open cluster in Scutum (RA 18 33 28.3, Dec -10 24 08)
Per Dreyer, NGC 6649 (= John Herschel's GC 4420, 1860 RA 18 25 44, NPD 100 29.5) is a "cluster, poor, a little compressed, pretty small, stars from 9th-10th and 12th-13th magnitude".
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 Above, a 12 arcmin wide region centered on NGC 6649 Below, a 20 arcmin wide region centered on the cluster

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