NGC 346, which resides in the Small Magellanic Cloud (SMC), is an open star cluster with surrounding nebulosity. At magnitude 10.3 and having a smallish size (~14 x 11 arcseconds), it is relatively easy to spot with a small telescope. This photograph was taken through H-alpha, H-beta, and OIII narrowband filters, which reveal the different densities of ionised hydrogen and oxygen gases in NGC 346 and the surrounding N66 gaseous region. My guess is that the apparent structural elements of the nebula in this image are likely the result of high-velocity stellar winds causing interstellar gas to pile up but I can't seem to find a good reference for this.
Although the SMC is a typical dwarf galaxy (that is to say, old and not creating many new stars), the NGC 346 & N66 region is a stellar nursery, shining with the light of many young, bright O-type stars. Nota et al. (2006) suggest that some are as young as 3 to 5 million years old (practically a baby, by stellar standards). The nebula also contains one of the brightest stars in the SMC - the very hot Wolf-Rayet star, HD 5980 - and the supernova remnant SNR0057-7226.
It is clear from this image that I'm still very much at the beginner's stage of narrowband imaging, although I'm encouraged by the fact that this time last year I had just started to consider using this sort of filtration. Actually, I'm still genuinely surprised when I can get any sort of an image with a procedure that is this complex. It is very rewarding, though, so I'll just strap on the mental crampons and continue to scale this learning curve.
Dates: 18 August, 2018; 25 August, 2018
R.A.: 00h 58m 51s
Dec.: -72° 11' 09"
Photo stuff: all filters 20x180s + 6x600s ea.; ISO 800 for the 180s subs; ISO 1600 for the 600s subs; Canon 60Da on the Meade RCX400 16" f/8
Post-processing notes: Narrowband composite created with MaxIm DL6; H-alpha(656.28 nm); OIII (486.00 nm); H-beta (500.70 nm); all 100%