We have a couple of those in the hallway at the technical campus I go to and i believe it has a rapid start electronic, ballast...one apparently is a 4 lamp and 2 lamp ballast as only the left four lamps were replaced

This is a full four-foot wide circle! I've never seen one open, but i could almost make out the lamps. They're definetly T8 though.

I've noticed those circle lights seem to be common during the 70s.

I saw one of these at my old High School! About the same size in the downstairs hallway by the office.

Yeah there are a few of these around the building. There's even the rare 2ft wide cirle. (I say rare as there are two in the whole building.)

I know of a subway station here built in the late 70s that's filled with two foot circle lights...they use two F40T12 U bends.

Hmm. Interesting that they're on the walls. I noticed here that the troffers downstairs (with the exception of the Unified Arts wing, which is Art, Computers/Technoledy, Spanish, and Italian) are all instant start, and boy do those lamps fry fast. These circle lights are programmed start as well as the troffers upstairs and the wraps upstairs. It seems downstairs (with the exception of the Unified Arts wing) was retrofitted at a different time, as those fixtures are all instant start while upstairs and in the UA wing has programmed start F32T8 fixtures. This is upstairs. Another interesting thing, is that is you look at the grid for the suspended ceiling in the classrooms, their black from the older T12 wrap lights that were once there before the troffers were put in.

Ironically, my elementary school from 1992-93 still has magnetic rapid start T12 wrap lights in the classrooms and drop lens 1X4 troffers in the hallways. The Library and Cafeteria at my elementary school have three-lamp F32T8 troffers, which is what they use at my middle school too. The T12 wrap lights at my elementary school are three-lampers while the 1X4 troffers are two-lampers. The cafeteria and library used to have these huge 4X4 six lamp F40T12 fixtures, but I think they were all replaced because the opal diffusers kept breaking. I still miss my elementary school because it was always fun watching the magnetic ballasts turn on the lamps. Programmed start fixtures are still pretty cool too, but they all have the same exact delay time versus magnetic RS, which they all bink on randomly.

UPDATE: these cool looking fixtures are gone now. Not sure what they did to cover up the openings. Perhaps the circle parts are still there and they just replaced the fixture above them. I saw some big 4x4 six lamp F32T8 fixture things near the dumpsters outside the school. I actually haven't been back in the building but I know they replaced all the lights with LEDs.

Ahh, they were pretty neat looking lights. Interestingly said subway station with the 2' round lights also got LED'd except they ordered round 2' LED fixtures so it still has a similar look. The only difference is that the new LEDs are 6500K vs the 4100K of the fluorescents and the LEDs have flat diffusers while the fluorescents had a drop dish diffuser.