N30 Complex

A striking complex of beautifully arranged stars

Image credit Robert Gendler

RA: 05h 22m 07s Dec: -67° 56′ 46″

Diameter: 12′ x 10′

OB Associations: LH 34, 36, 37, 38

NGC Objects: NGC 1869, 1871, 1873

With gorgeous orange mag 4.8 Theta Dor blazing splendidly due north of the huge N30 complex, it really is a striking sight!

N30 is huge, and encompasses four OB associations (LH 34, 36, 37, 38), that sweep northwest in a swathe of bright and faint stars. Three of them lie on the eastern side of the complex with three very different configurations of stars and swirls of nebulosity. Very eye-catching! LH 34 is a sprawl of stars at the northwestern end, housing three small clusters. Shapley used NGC 1869 as the centre of “Constellation IV”, a 33′ x 33′ association of blue supergiants.

LH 34 + N30 (OB Association + Emission Nebula)

RA 05 12 30.9 Dec -67 17 25 Mag – Size 16′ x 3′

16″ at 228x: LH 34 exhibits two lovely chains of bright stars, the larger one being a ragged 3′ ENE-WSW chain of six mag 12 stars lying on the NW flank of the complex. The other chain, lying just SE of the larger chain, consists of half a dozen fainter stars in an irregular arc, oriented ENE-WSW and open to the southwest. Three small objects lie in the larger chain: at 333x, open cluster SL 310 appears as a pair of faint stars, nebula BSDL 878 appears as a small, bright little droplet of light, and the cluster ZHT AN 16 appears as a smallish, moderately faint, irregular gritty glow of unresolved stars. With the UHC filter, there is no sign of any of N30’s nebulosity in the vicinity.

LH 36 + N30 = NGC 1873 (OB Association + Emission Nebula)

RA 05 13 54.0 Dec -67 20 06 Mag 10.4 Size –

16″ at 228x: LH 36 = NGC 1873 appears fairly bright, irregular, 4′ x 2′ in size, elongated E-W. A scattered collection of a dozen or so mag 13 and fainter stars and one lovely bright mag 11.6 star are set against a faint background haze of unresolved stars and nebulosity. There was a weak response to the UHC filter, the nebulosity appearing as a small, faint and very diffuse mist with no discernible edges, it simply faded away into the sky.

LH 37 + N30 = NGC 1869 (OB Association + Emission Nebula)

RA 05 13 53.0 Dec -67 22 48 Mag – Size 2′

16″ at 228x: LH 37 = NGC 1869 is lovely. It consists of mag 11.5 HD 269183 buried in the extremely faint glow of the nebulous BSDL 933, the mag 13.1 Wolf-Rayet star, Brey 17, and half a dozen faint stars, elongated 2′ x 1′ E-W, and all swathed in a faint mist of nebulosity with a noticeably brighter glow (N30A) to the southeast of HD 269183. There is a moderate gain with the UHC filter, the nebulosity appearing as an even, oval mist that extends off the cluster to the west, with N30A appearing as a patchy, off-round glow with fairly well defined edges. The rest of the nebulosity has no edges – the glow simply fades away.

LH 38 + N30 = NGC 1871 (OB Association + Emission Nebula)

RA 05 13 52.3 Dec -67 27 1 Mag 10.1 Size 3′ x 1′

16″ at 228x: LH 38 = NGC 1871 appears 3′ x 1′ in size, elongated E-W, in which 5 mag 11.5-13 stars and around half a dozen fainter stars are resolved, all wrapped in a soft hazy nebulous glow. Mag 11.8 HD 34664 and mag 11.3 HD 269195 are the ionising stars. N30B lies near the centre of the cluster, and it appears as a moderately bright, very small, non-stellar knot. A young stellar object, TIC 40717332 lies buried in it. Cluster KMHK 669 appears as a small, round, softly hazy smudge of faint light. There is a moderate gain with the UHC filter, the nebulosity appearing quite patchy, but with no edges, just a gradual fading away.

N30B is the unique double-bubble cocoon of dust surrounding a cluster of young, hot stars. N30’s wispy nebulosity can be seen surrounding it. Credit: NASA, Hubble Heritage Team