When I first spotted this small clamshell, it was kinda a mystery to me since I have previously not seen this luminaire. However I did suspect it could have been a Joslyn since the glass refractor is similar to the kind used on small sized Joslyn cobraheads (Joslyn's cobraheads are very strange looking, kinda like spaceships!). But I did not know for sure, so this luminaire remained a mystery. Then thanks to some literature I have seen, I finally know for sure, this luminaire is certainly a Joslyn. The large 400 watt sized one (looks the same as this one but larger) is called the MV-131. The 400 watt cobrahead is called the MV-141. Model names for the smaller sized Joslyns remain unknown, although I would assume this one is a MV-111, and the smaller cobrahead a MV-121...but I can't say for sure.
This Joslyn 175 watt was found on a residental street in Pasadena, CA, on a mercury-lit block. The other mercs are all GE cobraheads. The series incandescent radial waves are also found in the same vincity. This luminaire is actually powered by a 6.6 amp series transformer mounted on the crossarm of a nearby wooden utility pole, and wired externally to the luminaire's own pole.
