NGC 1961 is a galaxy in Camelopardalis constellation.
Its distance is 180 million light years and its apparent size is 4'x3'; it is the largest member of a small group of ten galaxies.
Due to its perturbed form on the southern spiral arm, it was also classified like Arp 184.
However there is no trace of an interaction with a companion.
Radio observation suggests that NGC 1961 is indeed an "intruder" inside the small galaxy group: by entering the group, this galaxy piles up the gas in the group medium, compressing it on its southern side, leading to the perturbation on the spiral arm that we see in the image.
(source: The Cambridge Photographic Atlas of Galaxies)
Optics Celestron C9.25 Edge HD f/10
Mount 10Micron GM1000 HPS
Camera Atik 4000 with Starlight Xpress filter wheel 5 positions
Filters Baader 50.8 unmounted
Guiding system OAG LB Astro Proxima with Lodestar
Exposure details L 18x600" bin1 -20C
Total integration 3h
Acquisition Maxim, PHD2
Processing Pixinsight 1.8, Photoshop CS5
Location Pian dell'Armà (Italy)
Date 20 September 2015