Thorn OSC 500 "Sunspot"
Narrow beam spot for 1 x 300w M38 or 1 x 500w M40 G9.5 halogen lamp.
I don't know when it was made but due to the fact it has "atlas" branding on it I would reckon on the early 1970's.

You can see the remains of the well-used Philips that came with it!
I saw the state of it and decided to bring it up to full power slowly on the variac. Afer a few minutes at full power it went POP! I must have had a nice arc as it not only took out the 20 amp circuit breaker on the variac's output... it also took out the 32 amp MCB on the main distribution board!

The lampholder has two hefty spring clips which contact the pinch seal area of the lamp which also makes contact with the heatsinked rear housing. Clearly an attempt at keeping the temperature of the lamp under control. They are just visible in the top photo.

Thorn OSC 500 "Sunspot"

Narrow beam spot for 1 x 300w M38 or 1 x 500w M40 G9.5 halogen lamp.
I don't know when it was made but due to the fact it has "atlas" branding on it I would reckon on the early 1970's.

You can see the remains of the well-used Philips that came with it!
I saw the state of it and decided to bring it up to full power slowly on the variac. Afer a few minutes at full power it went POP! I must have had a nice arc as it not only took out the 20 amp circuit breaker on the variac's output... it also took out the 32 amp MCB on the main distribution board!

The lampholder has two hefty spring clips which contact the pinch seal area of the lamp which also makes contact with the heatsinked rear housing. Clearly an attempt at keeping the temperature of the lamp under control. They are just visible in the top photo.

thorn400whipak2.jpg DPP00000721.jpg sunspot.jpg 5257241E-B379-455C-AC16-2F178EE857D2.jpeg 387A0028.JPG
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lantern_vision   [28 Apr, 2016 at 04:17 PM]
Those are just awesome FSB
lantern_vision   [28 Apr, 2016 at 04:18 PM]
One can install a msr broadway HMI 250 inside those? I see that the lamp bases are the same
AngryHorse   [28 Apr, 2016 at 08:56 PM]
Bet these are blinding with a HMI in!! Cool
James   [29 Apr, 2016 at 09:49 PM]
Smart design with the heatsink on the pinch seal, few companies go to such lengths today! The design is in fact from American Sylvania, but since Thorn and Sylvania used to share all technology from 1948 until 1991, there are many examples of one company making a product developed by the other. The Atlas brand disappeared in 1972 for general lighting, so these are pretty early.

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