Arp 273: Two Stretched Galaxies

OTA: OS 700
Camera: QHY 600
Observatory: Telescope Live, Sp (SPA-2)

Exposures:
RGBL: about 40' each
Total Exposure time used: 6 hours
Image Width: 20 arc-minutes

Processing Tools:
1.    Commercial: PixInsight, Topaz (Studio2, Photo AI2), 3DLUT Creator, Photo Director
2.    Pixinsight Addons: NoiseXTerminator, BlurXTerminator, StarXTerminator, Normalize Scale Gradient
3.    My Scripts: NB_Assistant, AC_Restar, Subframe Weighting Tool (Excel w/ J. Hunt)

Target Description:
Two galaxies in close proximity with their gravitational fields interacting and distorting one another. Together, they comprise Arp 273. The upper one is PGC8961, and the lower one is PGC8970. Before their encounter, both were spiral galaxies, and they still are, but now they do not have much of that "grand design" quality we often associate with spiral galaxies.

The long diagonal across Arp 273 spans but 3 arc minutes. The galaxies appear small because, of course, they lie at a considerable distance: 130M lightyears. For that reason, too, they are faint at about 13.7 magnitude, with a surface brightness much less—I calculated it to be about magnitude 17.

Processing Description:
More exposure time would have helped reveal more detail, but the 0.7m mirror helped offset that. I am working on a method to better incorporate L into RGB data. Better in that one would not distort the colors as severely as the current method (of putting the stretched L into the stretched RGB) does. I am now making a "super-L" image, linearly fitting it (in PI) to its inherent L, and putting that into the unstretched RGB image. This seems to work quite nicely. I believe the results could be improved if we had a tool to do histogram matching of unstretched images…but when I request the same, I get no helpful feedback. So, I am stuck with "linear fit" until some PI developer (or learned script writer) lends a hand.

Alex Woronow