Osram 250w MA/V run-up sequence

Just a sequence of photos taken during the run up of an Osram-GEC 250w medium pressure mercury lamp.

Note that the EV varies as I was trying to show how the discharge starts out filling the entire arc tube and gradually thins out as the lamp warms up.

It has a very interesting run up behaviour, the voltage across the lamp when starting is almost nothing at about 15 volts while drawing 3.4 amps from the ballast. This takes ages to come up and the lamp stabilised at around 128v at 2.15 amps.
It really was interesting to watch!

Note that internal reflections make it hard to see but the arc seems to like the right of the top electrode and the left of the bottom!