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A spectrum of a UHP short-arc MV lamp, in a media projector, at several of the reefs of Eilat's Coral World Underwater Observatory

A spectrum of a UHP short-arc MV lamp, in a media projector, at several of the reefs of Eilat's Coral World Underwater Observatory

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You can see how the mercury lines become broadened and merged with the continuous radiation from the ionised molecules.
Nor Max, James, Stan, light*plus and Globe Collector, posted a UHP spectra before, so I'm the first to do so, and the resolution is much better than this one .

IMG_0949.JPG IMG_0947~0.JPG IMG_0946~0.JPG IMG_0939~0.JPG

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Album name:dor123 / Lighting from our vacation in Eilat at Isrotel Yam Suf Eilat hotel Nov. 2015
Keywords:Miscellaneous
File Size:437 KB
Date added:Nov 11, 2015
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Date Time:2015:11:04 11:24:33
DateTime Original:2015:11:04 11:24:33
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lights*plus
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Nov 12, 2015 at 12:53 PM Author: lights*plus
Very interesting continuous spectrum, looks like the Hg lines are pressure broadened to the max permitted? But what causes the red radiation? I wish this was more defined (sharper). Do you have a photo of the lamp anywhere, or similar one on L-G?
dor123
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Nov 12, 2015 at 12:56 PM Author: dor123
I could only photograph the projector, but forgot to do this.

I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

I only working with the European date format (dd.mm.yyyy).

I lives in Israel, which is a 230-240V, 50hz country.

Medved
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Nov 12, 2015 at 01:21 PM Author: Medved
The MV does not generate that much broadened lines in the visible (as these are not the first order emissions), but really a "background" continuum (http://lamptech.co.uk/Spec%20Sheets/D%20ME%20Philips%20UHP120.htm)

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dor123
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Nov 12, 2015 at 11:41 PM Author: dor123
With my naked eyes, the spectrum was very close to what my camera captured, and the lines were indeed very broadened and almost merged with the continum. Not all short-arc projector MV lamps are Philips, there are Osram, Sylvania, etc... and of course generics.
In the graph, this might looks different than in a photo.

I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

I only working with the European date format (dd.mm.yyyy).

I lives in Israel, which is a 230-240V, 50hz country.

Medved
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Nov 17, 2015 at 02:33 AM Author: Medved
But the color is just the mercury and that is the same for all makers, so all mercury lamps follow the same "rules" (spectrum as function of the arc load).
What may vary is the arc loading, but that is just selecting one "operating point" from the dependence.

Other aspect is, not all projector lamps are UHP mercury only - some are MH (other components allow reasonable color with lower bulb loading, so allowing e.g. lower lumen packages and lower cost), some even Xenon (the other end of the power range, an extreme being the cinema projection "lamp grenades"),...

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lights*plus
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Nov 17, 2015 at 03:15 AM Author: lights*plus
I am not sure about a lower cost for projector lamps w/elements other than mercury. Hg compounds are readily available from many industries, and the US has the "Mercury Export Ban Act of 2008". So these mercury lamps must be cheaper to make (ok, maybe in the US & countries with abundant Hg) than with Xenon or other metal-halides.
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Nov 17, 2015 at 02:14 PM Author: Medved
Except the Xenon, the material cost is just a tiny fraction of the final lamp cost. What is the largest part is the processing cost (all the operations in making the final bulb from the raw materials). So when you have a lamp with lower operating temperature and/or pressure, the design would allow for a design (that includes material selection) easier to manufacture, so the processing cost will go down, even when some of the raw materials would be more expensive to obtain.
Here the lamps are sold integrated with the reflector - so the eventual difficulties in the application thermal management directly translate into the assembly cost as well (need for ventilation holes, many other details...)

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