N138 Complex
N138 is an intriguing complex for its almost magical response to the UHC filter

Image credit Robert Gendler
RA: 05h 24m 33s Dec: -68° 30′ 24″
Diameter: 300 x 280 light-years
Local OB Associations: –
NGC Objects: NGC 1949

N138, an often overlooked treasure in the Cloud
N138A = NGC 1949 (Open Cluster + Emission Nebula)
RA 05 24 58.2 Dec -68 28 41 Mag 12.4 Size 0.9‘
16″ at 228x: The beautifully bright and pearly sheen of round emission nebula N138A = NGC 1949, ~35″ in diameter, dominates the scene. No stars are resolved in the glow but there are a few mag 13 and fainter stars scattered about on its west and south sides. A string of 3 mag 13.7/12.8/13 stars extend to the southwest. There is a very faint, small, round sphere of ghostly pearl-coloured nebulosity bulging out to its southwest. Adding the UHC filter is little short of magical! The ghostly sphere is revealed to be a large, round, distinctly glowing emission nebula with a slightly brighter rim, especially to the southwest. NGC 1949, too, has a tremendous response to the filter; appearing rich, smooth and deep, with beautifully clear-cut edges. With NGC 1949 sitting on its edge, the large nebula looks just like a celestial ring set with a lovely pearl!
N138B (Emission Nebula)
RA 05 24 12.4 Dec -68 30 0 Mag – Size 0.4′ x 0.2′
16″ at 228x: Without the filter, small and bright N138B lies on the north-northwest edge of a large round glow of faintest nebulosity. It contains the small cluster HS 272 and with no filter (and at both 228x and 333x), no stars are resolved, it simply appears as a small and faint glow, with a mag 15 star attached to its southwest edge. The magic continues with the UHC filter! N138B is revealed as a bright, round glow, 20″ in diameter, with beautifully crisp edges, perched on the edge of a large and beautifully bright round emission nebula with a less-bright centre and lovely edges that melt into the starry background. A Wolf Rayet star, mag 14.8 Brey 29 lies at the centre of this big round glow (it is also the ionising star).
N138C (Emission Nebula)
RA 05 24 39.2 Dec -68 28 47 Mag – Size 0.7‘
16″ at 228x + UHC filter: Lying west of NGC 1949’s pearl ring, this small emission object appears as a very faint, 25″ arc-shaped wisp, open to the southwest wherein lies a mag 15.2 star (seen without the filter).
N138D (Young Stellar Object)
RA 05 24 14.0 Dec -68 29 49 Mag – Size –
16″ at 228x + UHC filter: It needed averted vision to pick up this tiny young stellar object, which appeared as a very small and very faint stellar glow; a very cool thing to see in this magical complex!