ARP 227 - Peculiar Galaxies in Pisces
ARP 227 - Peculiar Galaxies in Pisces
ARP 227 - Peculiar Galaxies in Pisces
In the 1960s, Halton Arp was an astronomer who produced a catalog of 338 unusual (peculiar) galaxies which had uncommon shapes to them. The vast majority of these galaxies have been warped by gravitational interactions with neighboring galaxies.

In this image, I've capture Arp's 227th set of peculiar galaxies. The largest galaxy in the lower right of the image is NGC 474, which has probably interacted with the blue spiral next to it, NGC 470. NGC 474 has a very large and faint shell, which can be tricky to photograph.

The large galaxy in the upper left of the image is NGC 467. Coincidentally, it too is a shell galaxy, although it appears to have no physical connection to NGC 474.

In this image, North is up. This image is cropped to 98% of the original full frame.

Exposure Details
Lens Nikon 600mm f/4 ED IF
Focal Length 600mm
Focal Ratio f/6
Mount Schaefer GEM - 7 1/2 inch Byers gear
Guiding QSI 690 OAG, Lodestar Autoguider, PHD2 Guiding
Camera QSI 690wsg-8 with Astrodon Gen II Series E LRGB filters
Exposure LRGB, 294:40:38:36 x 300 seconds (34.0 hours total exposure), all binned 1x1
Calibration 50 darks, 40 flats, 200 bias
Date October 13, 15, 16, 18, 21, 22, 23, and 24
Temperature Typically 45F to 60F on all 7 nights, sensor cooled to -10C (14F)
SQM Reading Bortle 4 on all 8 nights, typically 21.15 to 21.30.
Seeing 3/5 on 10/15, 10/21, 10/22, 10/23 and 10/24 ;4/5 on 10/13, 10/16, 10/18
Location Pine Mountain Club, California
Software Used Sequence Generator Pro for image capture, Astro Pixel Processor for calibration, pedestal addition, normalization, integration, and initial DDP stretching. Images Plus for star size reduction and noise reduction. Photoshop CS5 used for levels and curves, saturation adjustments, selective color, match color, screen mask invert and high pass filter. Gradient Xterminator for gradient removal. Carboni Tools for additional noise reduction and smoothing. Registar 64 for stack alignment. Focus Magic for focus restoration. PlateSolve 2 for plate solving.
Notes I started a big upgrade project for my work in October of 2017, and it kept me very busy and exhausted for the better part of 2 years. Work has finally slowed down enough that I'm having some time for higher priorities - namely my astrophotography!

So, after a 2 1/2 year hiatus, I am finally digging into my stack of data to begin processing some very old images. This astrophoto of Arp 227 is the very first one of these images, and it proves that my processing skills are quite rusty. I had to watch my own processing videos to try to relearn a huge number of processes that I have forgotten.

While this image certainly could have been better, I am quite happy with how well I was able to capture some of the very faint shells. And, it's encouraged me to continue to dig into my data stack and see if I can bring my processing skills back up to speed. I might want to try to give this one another try once that happens!

This image was selected by Nasa as the banner image for their press release announcing the discovery of a "cannonball pulsar" being ejected from CTB1. The astrophoto was also used in their video for the same announcement!