NGC 7793, a semidwarf galaxy in Sculptor.
The thumbnail is strongly cropped. The (revised, more data)
full image is here.
Taking the shot: We found this a bit difficult because there are only the most feeble of guide stars in the field if the galaxy is centred. On one night, we used those feeble stars and managed after a fashion. On the other two nights, we offset things a bit. Curiously, having a good guide star and three feeble ones was not hugely better (0.65 sec rms guide error) than just three feeble ones (0.75 sec rms), unimportant against 2.2 sec arc seeing, so we could perhaps have centred the galaxy after all.
What we saw: There are no obvious dust lanes here. Perhaps semi-dwarfs are tidy creatures. But there are some flocculent M83-style spiral arms with clumps of bright blue stars, and a nice salmon-pink centre of older stars. The whole effect seems almost three dimensional and rather pretty.
Squillions of small galaxies in the background, including a magnificent pair of interacting tadpoles at the left edge about 10 o'clock, and many other near face-on fellows 'with form' as the Bill would say.
Because of our indecision about where to point, there is no colour data for the extreme right hand edge, but we didn't crop it off because there's a cute galaxy there that we'd like to revisit.
Image details: Field 38' arc, 0.55"/pixel. North to the left. Lum 16 hours (1hr unbinned subs), RGB 2 hrs each (30 min 2x2). Aspen CG16M on 20" PlaneWave. Processing using GoodLook 64.
At last, after at least 120 mm of rain this month, three nights of imaging. The twitching and the craving subsides a little bit.
Cheers,
Mike n Trish
Edit:
Also attached is 3hrs in H-alpha (3x1hr unbinned), with the position of the microquasar (mentioned by Rick) marked with an arrow.
Further edit:
We acquired another 2.5 hours of RGB in each channel, for a total of 4.5 hours per channel, and reprocessed.