I've recently started a small 'programme' to observe brightness variations in bright quasars that can be seen in my 10" telescope and which can be viewed this time of year. I selected three quasars that are within reach, none previously known to me, one of which is 3C 66A (strictly speaking it's a BL Lac object). As beginner's luck would have it, in my first two obervations about a month apart I've seen 3C66A brighten by about half a mag to around 14.5 by my reckoning (using comparison stars as a visual guide). The standard argument is that the light source that's varying in output can't be much larger than ~ 1 light-month across.
After my first observation I decided to do some reading up on the object and it's environment and found a radio map of it overlaid on an optical image (see lthe link below). The quasar is the red blob on the far right of the image and, unknown to me previously, I found there's a radio galaxy (3C 66B) nearby which has jets coming out of it. Somewhat unexpectedly and as an aside, I was also able to glimpse the B galaxy with averted vision during the second observation, despite it being ~15 mag. Anyway, the wider environment reveals an Abell cluster of galaxies.
This pair obviously struck me as a typical Arp pairing but having looked through his books I can't find any mention of it, although I note that "Seeing Red" discusses the Perseus-Pisces chain that runs past the bright galaxy NGC 891 (which is quite close to 3C 66A). Anyway, by accident I seem to have bagged an interesting quasar-galaxy pair. I'm waiting for the Moon to get out of the way before I can make my third observation (poor Moon, unloved).http://www.cv.nrao.edu/~abridle/3c66bdigss.htm