Used a better camera to take a closer shot of THIS light. Within the past 6 months this fixture has received a new photocell (not sure why, it wasn't day burning or out) and a new lamp. I believe this fixture is from the 70's.
Was the lamp dim? If so that could also be a reason. Narragansett Electric always replaced the PC and lamp together so they could easily tell when it was last serviced by looking at the 2 digit date on the top of the PC casing. NGrid also does this but I don't think they always do it. Sometimes a dayburning unit will just get a new PC, not a lamp and the opposite for a burned out fixture. If the problem is a broken lens it's pretty much a wildcard.