NGC 1698 = ESO 056-006 = S-L 45 = KMHK 115

04 49 04 -69 06 54; Dor
V = 12.1; Size 1.5‘

30″ (11/6/10 – Coonabarabran, 264x): fairly bright, moderately large, irregular glow, 1′ diameter. Roughly 10 stars are resolved in the outer halo giving a triangular shape. NGC 1698 forms a close pair with KMHK 118, a much smaller and fainter cluster 1.6′ SE. It appeared as a faint, small glow, 20″ diameter with no resolution. Mag 10.3 HD 268647 lies 5′ SSE and IC 2105, a bright compact HII knot, is just 0.6′ SSE of this star.

Notes: John Herschel discovered NGC 1698 = h2677 on 23 Dec 1834. He noted “pB; R; gradually little brighter middle; 60″; resolvable.” Although only observed on a single sweep his position is good.

 

KMHK 118

04 49 21 -69 07 36; Dor
Size 0.4′

30″ (11/6/10 – Coonabarabran, 264x): picked up 1.7′ SE of NGC 1698 as a faint, small glow, 20″ diameter, no resolution.

 

IC 2105 = LMC-N77A = ESO 056-7 = HD 31351

04 49 26.4 -69 12 03; Dor
V = 12.8; Size 0.4′

30″ (11/6/10 – Coonabarabran, 264x): bright, small, round, compact, high surface brightness, 25″ diameter. A mag 10.3 star lies just 0.6′ NW of center. Located 5.5′ SSE of cluster NGC 1698. The NGC 1727 complex (N79) lies ~17′ SE. IC 2105 is the brightest knot in the N77 complex, mostly visible as very faint haze to the east (N77E).

Notes: Williamina Fleming discovered IC 2105 = HN 84 on Harvard objective-prism plates from Arequipa, Peru. It was included in a 1901 table “Objects having peculiar spectra” (ApJ, 14, 144-146), based on its emission spectra. In 1926, Robert Innes observed the nebula with the 26.5-inch refractor of the Union Observatory in Johannesburg. He noted it as “20 arc second diameter, resolvable.” He added the comment that 15 seconds preceding [should read following] there is a small faint and nebulous patch.” The nebulous patch is part of LMC-N77.

 

NGC 1712 = ESO 056-011 = S-L 60 = LMC-N79 = LH 1

04 50 59 -69 24 30; Dor
V = 9.9; Size 4’x3′

25″ (10/27/22 – OzSky): at 187x; elongated group of mostly faint stars ~ 4′ in diameter with a wide mag 10.7/12.4 pair at the south edge. The brighter star is a yellow LMC supergiant. The background was an uneven hazy glow, but when I added a NPB filter the object dimmed. Increasing to 318x, the glow mostly disappeared and at least 30 stars were resolved, showing it’s a large, rich cluster (part of OB association LH 1). Close west of NGC 1712 is a 5′ chain of stars trending N-S with mag 13 to 14.5 stars.

18″ (7/10/05 – Magellan Observatory, Australia): first of three clusters with nebulosity including NGC 1722 + IC 2111 4′ NE and NGC 1727 8′ NE. At 128x it appeared as an irregularly shaped 4′ nebulous haze, situated just north of an attractive mag 10.7/12.4 double star (17″). A half dozen faint stars are embedded in the haze (part of N79) besides the two brighter stars at the south edge. This is a young LMC cluster and forms the western portion of association LH 1.

18″ (7/9/02 – Magellan Observatory, Australia): this is the first of three nebulous LMC clusters with NGC 1722 3.9′ NE and NGC 1727 7.7′ NE. NGC 1712 appears as a fairly large knotty region of stars and possible weak nebulosity (within N79), ~4′ diameter. A mag 10.7/11.5 double (separation 17″) is at the south edge.

Notes: James Dunlop discovered NGC 1712 = D 111 (or D 112) = h2685 on 24 Sep 1826. He noted D 111 as a “small faint nebula” and his reduced position was ~10′ too far ESE. But in the drift (second on this date) he placed it 27′ due north of 7th mag HD 31518 (he also began at this star on the first drift). NGC 1712 lies exactly at this offset. The next two objects in the drift, D 112 and D 113, apply to NGC 1722 and NGC 1727.

John Herschel made a single observation on 24 or 25 Dec 1834 (sweep 523) and reported “a pB, S, cluster.” Herschel didn’t reference Dunlop’s possible earlier observations due to the poor match in position.

 

NGC 1722 = LMC-N79 = ESO 056-012 = LH 1

04 51 43 -69 23 54; Dor

25″ (10/27/22 – OzSky): at 187x; unfiltered this is an unimpressive 2′ patch with a few resolved stars and dominated by IC 2111 (N79A), a bright 15″ knot with a stellar point (N79B) attached at its NE end. A mag 12 star lies ~0.5′ SW of IC 2111, a mag 10.7 star (blue supergiant HD 268718) is 2′ SSE and mag 8.5 HD 31722 is 3′ ESE.

There was a strong response to a NPB filter: high surface brightness IC 2111 brightened significantly and the attached stellar knot N79B had an excellent filter response. In addition, a 30″ diffuse patch of nebulosity (MCELS L-24) was evident 1′ S of IC 2111 and immediately SE of the mag 10.7 star.

18″ (7/10/05 – Magellan Observatory, Australia): NGC 1722 is part a small group of LMC clusters with nebulosity (N79) including NGC 1712 and NGC 1727. At 128x it appeared as a fairly faint, irregular hazy region with a few resolved stars and highlighted by IC 2111, a small, bright knot. The nebulosity has a good response to the UHC filter. Located 4′ SW of NGC 1727. This is a very young open cluster with an unevolved main sequence and forms the eastern component of stellar association LH 2.

18″ (7/9/02 – Magellan Observatory, Australia): the second of a trio of LMC clusters and nebulosity at 128x and UHC filter. At the core is a small, bright 15″ knot = IC 2111 and surrounding this is a larger 2′-3′ group of faint haze and some stars. NGC 1727 lies 4.5′ NE and NGC 1712 3.9′ SW.

Notes: James Dunlop discovered NGC 1722 = D 112 (or D 111) = h2689 on 24 Sep 1826. He described D 112 as a “double nebula, 15 seconds distant, 15″ diameter.” The next object in the drift was placed 15 seconds following and 5′ north, which is a very good match with NGC 1727.

John Herschel made three observations (first on 3 Nov 1834, sweep 509). On 11 Nov 1836 (sweep 748) he called it “The second of a series of clustering patches.” Herschel didn’t reference Dunlop’s possible earlier observation due to his poor reduced position.

Joseph Turner observed and sketched NGC 1722 on 13 Nov 1876 with the 48″ Great Melbourne Telescope, though he misidentified the field (NGC 1722 was assumed to be NGC 1743). His sketch, published as Plate III, figure 22 in “Observations of the Southern Nebulae made with the Great Melbourne Telescope from 1869 to 1885. Part I. Melbourne”, shows a very elongated, curvy nebulosity oriented N-S with two or three stars in a line near the center and two more at each end.

NGC 1722 is plotted as a planetary nebula on the Planetary on the Skalnate Pleso “Atlas of the Heavens” as well as the first edition of the Sky Atlas 2000.0, because Fleming identified IC 2111’s spectrum as class P = planetary.

 

IC 2111 = LMC-N79A = ESO 056-013 = H72.97-69.39 = MCELS L-25 = HD 31673

04 51 52.2 -69 23 31; Dor

25″ (10/27/22 – OzSky): at 187x; NGC 1722 is dominated by IC 2111 (N79A), a bright 15″ knot with a stellar point (N79B) attached at its NE end. A mag 12 star lies ~0.5′ SW of IC 2111, a mag 10.7 star (blue supergiant HD 268718) is 2′ SSE and mag 8.5 HD 31722 is 3′ ESE. There was an strong response to a NPB filter: high surface brightness IC 2111 brightened significantly, and the attached stellar knot (probably N79B) had an excellent filter response. In addition, a 30″ diffuse patch of nebulosity was evident 1′ S of IC 2111 and immediately SE of the mag 10.7 star.

18″ (7/10/05 – Magellan Observatory, Australia): this LMC emission nebula/cluster appeared as a very small, high surface brightness knot, ~12″ diameter, embedded within NGC 1722. A mag 12 star (RMC 54F) lies ~0.5′ SW, a mag 10.7 star (blue supergiant HD 268718) is 2′ SSE and mag 8.5 HD 31722 is 3′ ESE.

18″ (7/9/02 – Magellan Observatory, Australia): embedded within NGC 1722 is a small, fairly bright knot just NE of a mag 11.8 star. At 128x and UHC filter, it appeared ~15″ diameter and was described by Williamina Fleming as a “stellar planetary” based on an objective prism plate.

Notes: Williamina Fleming discovered IC 2111 = HN 85 in 1901 on Harvard objective prism plates from Arequipa, Peru as part of the Draper Survey (HD 31673). She noted “Planetary, stellar”. NGC 1722, the surrounding nebula, is plotted as an planetary nebula on the Skalnate Pleso “Atlas of the Heavens” as well as the Sky Atlas 2000.0

 

LMC-N79B = [M2002] 12005 = HSO BMHERICC J072.9711-69.3911 = H72.97-69.39

04 51 53.1 -69 23 28; Dor
V = 12.5

25″ (10/27/22 – OzSky): this stellar HII knot is attached on the NE end of the bright, 15″ knot IC 2111 (N79A) within NGC 1722. At 187x, it appeared stellar and I wasn’t sure if it was just a star. But when I added a NPB filter there was an excellent filter response!

Notes: This stellar knot is identified as N79B in SIMBAD, though Mati Morel assigns this designation to a star with faint nebulosity 35″ E of NGC 1722.

A 2017 preprint reports “the discovery of a massive embedded star forming complex spanning about 500 pc which manifests itself as a younger, embedded twin of 30 Doradus. Previously known as N79, this region has a star formation efficiency exceeding that of 30 Doradus by a factor of about 2 as measured over the past ~0.5 Myr. Moreover, at the heart of N79 lies the most luminous infrared (IR) compact source discovered with large-scale IR surveys of the LMC and Milky Way, possibly a precursor to the central SSC of 30 Doradus, R136.” The listed position, 04 51 53.3 -69 23 29, is just immediately northeast of IC 2111.

 

LMC-N79C

04 52 02.0 -69 20 36; Dor
Size 0.8’x0.8′

25″ (10/27/22 – OzSky): along the west edge of the irregular NGC 1727 complex is the small nebulous patch N79D. Unfiltered at 187x, a single, easily visible mag 14.4 star is centered within the glow. It brightens up well with a NPB filter as a roundish glow, about 45″ diameter. This gives NGC 1727 a sharper edge along the southwestern side.

 

NGC 1727 = LMC-N79E = ESO 056-014 = S-L 67 = LH 2

04 52 11.5 -69 20 13; Dor
V = 11.1; Size 2.8’x2.0′

25″ (10/27/22 – OzSky): fairly large (up to 4′ diameter with NPB filter) and bright nebulous cluster (N79E) with a couple of brighter patches. Roughly a dozen stars were resolved (LH 2) unfiltered in the main group at 318x, along with one of the SE side and one at the W side. There was a strong response to a NPB filter at 187x. The main glow appeared elongated E-W and roughly oval.

On the west side is a brighter patch (N79C) about 45″ diameter with a mag 14.4 central star unfiltered. This gives NGC 1727 a sharper edge along the southeast side.

Unfiltered, indistinct faint haze surrounding a single 14th mag star is barely off the SE end. Adding a NPB filter, it appeared as a fairly well defined, bright circular glow (N79D) about 1′ diameter. N79E, N79C and N79D were encompassed within a very irregular contiguous glow.

18″ (7/10/05 – Magellan Observatory, Australia): fairly bright, fairly large, irregular patch, ~2.5’x1.5′, with at least a half-dozen mag 13 stars resolved. This LMC cluster with nebulosity (N79E) responded well to a UHC filter at 128x. The western section is catalogued as N79C. A small extension was visible to the southeast consisting of cluster KMHK 187 (no stars were resolved with filter) and emission nebula N79D, increasing the size to ~3.5’x1.5′. NGC 1727 is in a group with NGC 1722 4′ SW and NGC 1712 7.5′ SW. Located 4′ N of mag 8.5 HD 31722. This is a very young cluster or association (LH 2) with an unevolved main sequence similar to nearby NGC 1722.

18″ (7/9/02 – Magellan Observatory, Australia): at 128x and UHC filter this is a fairly large elongated patch of nebulosity, ~3.5′ diameter with a group of mag 12-13 stars superimposed. A smaller detached piece of nebulous haze (N79D), ~1′ diameter, is close southeast. This is the 3rd (and 4th) in a chain of objects with NGC 1722 4.5′ SW and NGC 1712 8′ SW. A mag 8.5 star (HD 31722) is 4′ SSE.

Notes: James Dunlop discovered NGC 1727 = D 113 = h2690 on 24 Sep 1826. He described D 113 as a “small faint nebula, oval, 12″ or 15″ diameter” and placed it 15 seconds of time following and 5′ N (in his handwritten drift log) of D 112 = NGC 1712/1722. This is a good match with NGC 1727, although his reduced position is off by nearly 20′.

John Herschel rediscovered NGC 1727 = h2690 on 3 Nov 1834 (sweep 509). He noted “a rather poor irreg R cluster. (Sky Hazy)”. In Dec 1834 (sweep 523) he recorded “A cluster, pB, pmE, 3′ l, 90″ br; stars 12m”

Joseph Turner observed and sketched NGC 1727 on 13 Nov 1876 with the 48″ GMT, though he misidentified the field (NGC 1727 was assumed to be NGC 1745). His sketch, published as Plate III, figure 22 in “Observations of the Southern Nebulae made with the Great Melbourne Telescope from 1869 to 1885. Part I. Melbourne”, shows an irregular, elongated E-W nebula with roughly 10 stars involved. The sketch also shows a small, round nebula to the SE of NGC 1727, which is LMC-N79D.

 

LMC-N79D = KMHK 187

04 52 27.5 -69 21 44; Dor
Size 1.2’x1.0′

25″ (10/27/22 – OzSky): this patch of nebulosity is part of the N79 complex and is situated just 2′ SE of the bright nebulous cluster NGC 1727. At 187x unfiltered, indistinct faint haze surrounded a single 14th mag star. There was an excellent response with a NPB filter and it appeared as a fairly well defined, bright circular glow about 1′ diameter that hangs off (barely attached) the southeast side of the NGC 1727.

18″ (7/10/05 – Magellan Observatory, Australia): this is a small extension or barely detached piece off the SE end of NGC 1727 in the LMC. SIMBAD identifies this nebula as cluster KMHK 187 (from Kontizas et al, “The cluster system of the Large Magellanic Cloud” in Astron. Astrophys. Suppl. Ser., 84, 527), though it was first catalogued by Henize (79D) as an emission object.

Notes: Joseph Turner discovered LMC-N79D on 13 Nov 1876 with the 48″ GMT, though he misidentified the field as containing NGC 1737, 1743, 1745, 1748. His sketch was published as Plate III, figure 22 in “Observations of the Southern Nebulae made with the Great Melbourne Telescope from 1869 to 1885. Part I. Melbourne”. The object he assumed was NGC 1748 is LMC-N79D = KMHK 187 and was drawn as a round nebula close southeast of NGC 1727 with a single star involved at the center.