I have had this lamp for a while now, it was a thrift store find! Its cool to see the insides of the HPS arc tube since its clear! Geoff, Max and James also have at least one example of this type.
To this day I still can't believe you found THIS in a thrift store! I haven't seen an HID lamp or fixture in a thrift store in my area for over a decade. Fluorescent tubes and vacuum tubes also used to show up...not anymore.
because this is a relative expensive technology whose high cost does not justifies the limited improvement in efficacy associated with the use of sapphire in discharge lamps. Thirty years ago there was some interests in using this material in sodium lamps because PCA was more less transparent at the time than now. The introduction of chemical polishing, of hot pressing and other techniques has led to a considerable improvement of PCA burners, which made the use of expensive sapphire less and less interesting.
Aren't only the S56 (100V arctube) and the retrofit 150w HPS lamps in the BT 28 shape? While the more common S55s have the BT 25 shape? At least that's what it seems like to me.
Yeah, I bought them. I know cwhat auction you're talking about. I was watching it to see how high it went. I didn't plan on bidding as I already have a 150w. Odly enough the one that seller had, had the same markings on it as mine do. That same seller also had a couple nos 400w mv lamps a week earlier I was able to buy.
Nice catch. Are yours labeled "PROPERTY OF NYC"? The one I saw in the auction was, making it even more elusive. I was after the mv lamps at first since there was the clear sylvania and DX flavor, both from the 70z. After reading the listing, I was like "gimme!"
Yes, mine have the property on NY markings on them. I had really taken note of that auction due to the corstar as I already had the others and really wanted to see how high the bidding went. I was actually a little surprised that the bidding didn't go higher. I've seen med pressure mv lamps go for upwards of $200 per lamp and I see those more than to elusive rare corstar bulbs. The 250w lamps I just got are just marked with the standard etch westinghouse used at the time.