| Designation(s) | Arp 159, NGC 4747 |
| Object Type(s) | Galaxy |
| Relevant Catalog(s) | All (Chron), Arp, NGC |
| Arp Category | Galaxies disturbed by interior absorption |
| Obs. Lat/Long | 42° 17', 073° 57' |
| Constellation | Coma Berenices |
| Date and Time Observed | 2026-07-10 22:56:00 |
| Instrument | EdgeHD 8" w/f7 reducer-1,422mm FL |
| Camera | Player One Apollo-M Mini |
| Image Details | Up is 269.8 degrees E of N. Transparency: Fair. Seeing: Fair. Total integration time was 43n 20s. Exposures 20s@225g. Darks subtracted, no flats. Dithered and recentered in SharpCap. No guiding. |
| Description | This is a revisit to a fascinating and challenging observation. NGC 4747 is a barred spiral galaxy categorized by Arp as exhibiting "disturbances due to interior absorption" which seems reasonably apt in this case. Arp's remarks note: "Very faint plume extending NE." The plumes are pretty clear; "internal abosorption" is a little trickier. The bright core, normally centered as a single circle of oval, now consists of 4 knots pushed off center. The faint plume isn't so faint in my capture (monochrome CMOS cameras being so sensitive). It turns out that the plume is a tidal tail caused by interactions with a nearby galaxy NGC 4725. I returned on July 12 to observe both galaxies together. There you'll find a full discussion of Tidal Tails, of which this is an example. |
| Related Observations | Arp159 (3) NGC4747 (2) |
| Catalog Links | |
