| Designation(s) | Arp 101, UGC 10164, UGC 10169 |
| Object Type(s) | Galaxy |
| Relevant Catalog(s) | All (Chron), Arp |
| Arp Category | Spiral galaxies with elliptical companions on arms |
| Obs. Lat/Long | 42° 17', 073° 57' |
| Constellation | Serpens |
| Date and Time Observed | 2024-06-13 23:07:00 |
| Instrument | EdgeHD 8" f10-2,032mm FL |
| Camera | ASI294MC-Pro |
| Image Details | Up is 181.1 degrees E of N. Total integration time was 28m. Exposures 30s@305g, UV/IR Cut Filter. Darks subtracted, no flats. Dithered and recentered in SharpCap. No guiding. |
| Description | The Uppsala General Catalogue of Galaxies (UGC) lists 12,921 galaxies visible from the northern hemisphere, first published in 1973. The fact that the two key galaxies in Arp 101 are listed in UGC (and not NGC or IC) underlines how obscure they are. Neither is in Astrometry.net's annotation system. We flipped our image 90° clockwise to match the orientation in Arp's catalog, which means south is up. The more southerly galaxy UGC 10164 (upper) is the "eliptical" galaxy referred to in Arp's categorization at magnitude 14.7; its spiral companion UGC 10169 is 14.9 (the spiral structure is barely evident in my capture and only slightly more clear in Arps'. The critical features are the bridge between the two galaxies and the extended tail on the spiral 10169, which are substantially fainter yet. Suggesting that the bridge between the two galaxies represents a companion "on the arm" of 10169 seems a bit of a stretch (pun intendend). During the capture in SharpCap my emphasis was on showing these connections and not worrying about the background noise or darkness. I wasn't sure if I'd be successful in capturing them, especially given there was a 50% illuminated moon during the capture. I was pleased with the result. I had to cut this observation short due to high clouds starting to trigger the brightness and FWHM filters in SharpCap. |
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