Arp 313 / NGC 3995 / NGC 3994 / NGC 3991
| Designation(s) | Arp 313, NGC 3995, NGC 3994,NGC 3991 |
| Object Type(s) | Galaxy, Galaxy Cluster |
| Relevant Catalog(s) | All (Chron), Arp, NGC |
| Arp Category | Groups of galaxies |
| Obs. Lat/Long | 42° 17', 073° 57' |
| Constellation | Ursa Major |
| Date and Time Observed | 2026-03-28 00:42:00 |
| Instrument | EdgeHD 8" w/f7 reducer-1,422mm FL |
| Camera | Player One Apollo-M Mini |
| Image Details | Up is 89.7 degrees E of N. Transparency: Good. Seeing: Fair. Total integration time was 28m20s. Exposures 20s@225g, No Filter. Dithered and recentered in SharpCap. No guiding. |
| Description | ARP 313 is a trio of interacting galaxies. The biggest member in the center is NGC 3995, to the west (upper right) is NGC 3994. The glowing galaxy to the northwest (upper left) is NGC 3991. Arp was taken with them, pointing out, "Linear strings of knots like deformed spiral arms. Strong [O II] emission" The "knots" presumably referr to both the distended arm of NGC 3995, and the entirety of 3991. The "strong [O II] emission" indicates what we today call a LINER galaxy, usually fueled by evolved, hot stars or a weak active galactic nucleus (AGN), presumably 3995. There's also a smudge below 3995, which could be a distant, edge-on galaxy, or perhaps a compact dwarf galaxy. Considering I had to shut down because I was pushing up against transit, the image is pretty good. Of course the telescope was pointing nearly vertical and away from the moon, so the atmosphere was cooperating as best it could. |
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