This Optispan lamp had most likely an external ballast fitted. Put in a 100 Watt ballast and a 150 Watt HPS lamp to make the light a bit more orange. The unit seems to work very well.
We are now replacing all our hps fittings with leds, which are junk. When they fail the entire fitting has to be scrapped creating more WEEE than a few ballasts over the years. Sad times. I liked to play with different lamp ballast combinations on the bench to see what would happen. FYI you can strike them with a fluorescent starter if you don’t have an igniter. All the best.
I love HPS lamps. Sadly they've all been replaced with LED here now :( which I i personally dont agree with, because HPS are actually more efficient than LED's. And their colour spectrum is way nicer for preventing sleep issues. They dont affect our sleep cycle very much because they dont emit any blue light. I guess the only reason for replacement is due to their tiny Mercury contents, which theyre actively trying to get rid of
