NGC 3718/3729
NGC 3718 is an unusually shaped galaxy located approximately 48 million light years from earth, appearing in the constellation Ursa Major. The galaxy has an S-shape and a dust band crossing the central bulge. The dust band likely characterizes it as a polar-ring galaxy. Both the dust band and the unusual S shape are thought to be formed by interaction with NGC 3729. Both galaxies have strong star formation, likely influenced by their interaction.
Interesting to me is that the bright grouping of galaxies near NGC 3718 is not interacting. This group of galaxies is catalogued as Hickson Compact Group #56 by Paul Hickson in 1982, and they are much more distant from earth, at nearly 400 million light years. Hickson catalogued compact galaxy groups with unusual features.
Processing
Processing was with PixInsight utilizing the RC Astro plugins. I again used the Multi-Scale Adaptive Stretch tool in PixInsight to stretch with only minor touch up following that. I actually gathered 3 nights of data on this target, but struggled to get acceptable flats on the 1st two nights due to a wide temperature variation between the outside and the inside where I have a screen large enough to cover the 8″ aperture. Additionally, the 1st two nights were plagued with sporadic clouds. I ended up discarding those nights entirely and improving the results.
Technical Card
Mount: Celestron AVX
Camera(s): ZWO ASI 2600mc pro, ZWO ASI 220 mini guide camera on an OAG
OTA: Celestron C8 SCT with 6.3 reducer
Filters: None
Exposure: 120 Lights @ 180 seconds
Annotated Image
This is a galaxy rich area of the sky, and a number of other galaxies are visible in the image.
Sweetman Astrophotography 