I'm on a Sculptor roll....and NGC 253 still to come. I have had so many clear nights that I captured the data for NGC 55 in a week.....i.e. one new Moon period. That is unheard of!

NGC 55 is one of my favourite galaxies and with a Dec of -39 deg, compared to my latitude of 33 Deg South, it is nearly overhead at its zenith. From its distance and apparent diameter of 32.4' it is straightforward to calculate the galaxy is about 60,000 light years across or about 55% of the diameter of the Milky Way.

Clearly we are seeing this galaxy edge-on.  It is deemed to be a Magellanic type barred spiral galaxy, although how they know it is barred given the orientation is unknown to me.

The Hydrogen Alpha emissions in this galaxy are very strong, I presume in part due to the edge-on aspect, which means we are looking through a lot of the galaxy on one side. I have produced a much more subtle Ha inclusion compared to my 2021 version of this galaxy and I feel that is a big improvement. 

Star clusters and perhaps some massive OB supergiant stars can be resolved. Most blue giant stars fall into the O spectral class, and most of them occur in OB stellar associations, which are small clumps of hot and massive stars that are thought to have originated at about the same time, and from the same molecular cloud. Revision B, which can be accessed via the mouse-over gives a cropped in and more detailed view of the amazing structures visible in this galaxy.

What I am most pleased about with this image is that the central bulge, about 1/3rd of the way along from the right hand extremity has a yellow hue and this can be made out right through the intervening spiral arms. Of course, the central core of such galaxies often has a core of older yellow-orange-red stars.

Here is some further information from Wikipedia (abridged):
“NGC 55 is a Magellanic type barred spiral galaxy located about 6.5 million light-years away in the constellation Sculptor. Along with its neighbour NGC 300, it is one of the closest galaxies to the Local Group, probably lying between the Milky Way and the Sculptor Group. It has an estimated mass of (2.0 ± 0.4) × 1010 M☉. NGC 55 and the spiral galaxy NGC 300 have traditionally been identified as members of the Sculptor Group, a nearby group of galaxies in the constellation of the same name. However, recent distance measurements indicate that the two galaxies actually lie in the foreground. It is also likely that NGC 55 and NGC 300 form a gravitationally bound pair. The Webb Society Deep-Sky Observer's Handbook writes the following about NGC 55: ‘Nearly edge-on and appears asymmetrical with some signs of dust near the bulge, which is diffuse, broad and somewhat elongated with the south edge sharp; southeast of the bulge it is strongly curved and lined with 4 or 5 faint knots; north edge of the curve is sharp.’ Burnham calls it ‘one of the outstanding galaxies of the southern heavens’, somewhat resembling a smaller version of the Large Magellanic Cloud.” 

It has more recently been estimated to be 6.07 ± 0.23 Mly away and has an apparent diameter of 32.4′ × 5.6′.