I foudn this bulb last year among a lot of like 500 bulbs in a flea market. I couldn't take them all, so I had to choose LOL. I didn't have any 150W daylight lamp so I grabbed it.
Probably 30 or 40 years old. But that sort of Daylight shares nothing with today's Sylvania daylight lamps. I guess the old incandescent daylights were popular before fluorescents came out in the late 30s.
It's around '85-'95 or so. In the 70s they were still made in stained glass. Nice find BTW! I got something like yours a while back its a 100w A-23 made around 2000 with a newer etch.