Object: ARP 263 (NGC 3239) | Date: 2016 April 6 |
Peculiarity: Irregular clumps. | |
Constellation: Leo | Time & altitude: 22.15 UT 54º |
Catalogue data: | Seeing (5 high): 4/5 |
R.A: 10h 25m | Transparency (5 high): 4/5 |
Dec: +17º 10 | Telescope: 0.5m f4.1 Dob. |
Magnitude: 11.4 | Eyepiece: 8mm Ethos x260 |
Galaxy size (mins): 5 x 3 | Filters: None |
Notes: Taken with Arp 7 seen an hour earlier, these two galaxies demonstrate how surface brightness affects visibility. Arp 7 is 14.5m and tiny while Arp 263 is 11.4m but large. Arp 7 was easy and obvious despite being low in the sky while Arp 263 needs AV to see much at all, even though better placed. A 9th magnitude star is superimposed on it and is a distraction. It is hard to trace the halo’s extent and edges. It is irregular and seems to wrap around the star. A brighter knot could be made out to the N of the star and another smaller knot, which may be double, lies to the E. |