Arp 81

ARP 81 2015 Aug 22

Object:            ARP    81

(NGC 6621 & NGC 6622)

Date:               2015 August 22


Peculiarity:    Spiral: large high surface-brightness component on arm.
Constellation:           Draco Time & altitude: 23.20 UT     61º
Catalogue data: Seeing (5 high):                               3/5
            R.A:                18h 13m Transparency (5 high):                   3/5
            Dec:                +68º 22 Telescope:     0.5m f4.1 Dob.
            Magnitudes:  13.6 & 16.0 Eyepiece:      8mm Ethos      x260
            Galaxy sizes: 2 x 1 & 0.5 x 0.4 Filters:            None.


This object is aligned NW-SE. The NW component (NGC 6621) is easily the larger and brighter. The most striking feature is a clear diagonal separation between the two components, a bit like the main dust lane crossing M82. A haze seen a little distance S on the same NW-SE axis in fact seems to be due to four unresolved stars when I compare to a CCD image. Arp’s filament on the NE side was not seen.