I observed them this weekend. This galaxy trio reminded me of the NGC 2964 / 2968 / 2970 trio, which was object of the month 03/2018 at the German astrotreff forum. Two brighter galaxies and one smaller and fainter galaxy.
In my 12" Dobsonian at 275x magnification and wide-angle eyepiece all the 3 of them fit into the field of view together.
NGC 3169
I saw a stellar nucleus, surrounded by an oval glow and a diffuse outer region that was rather diffuse at its northwestern side. At the eastern side it was sharper.
NGC 3166
Its surface brightness declined gradually from center to outer regions. Surrounded by a diffuse glow.
NGC 3165
Diffuse, elongated and slightly brigther at the center.
I also observed NGC 3156, which is located approximately 25 arc minutes southwest of the Holmberg 173 trio. According to its radial velocity it seems to be gravitationally tied to the trio. So is it actually a galaxy quartet?
Reply With Quote