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What is this lamp?

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Postby island » Thu Apr 07, 2005 3:04 pm


This is a 375mm lens on display at Montauk Point. The Markings: "I.L.P. 768-4" and "No. 397" appear on the housing. It is a clear Fresnel with a red cylinder covering the lens.
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http://www.lilighthousesociety.org/hist ... rvey11.htm
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Postby Optics » Sun Apr 10, 2005 7:21 am


This appears to be a lightship lantern. Some lightships had 4 of these mounted around a mast and some had 1 or 2 of these mounted at the top of a mast or masts. It could also be a pole lantern, but appears to be too big for that job.
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Postby plebetkin » Mon Apr 11, 2005 8:32 am


it looks similar to one of the pole lamps that was on the Portsmouth Lighthship. Were these lights common?
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Postby island » Mon Apr 11, 2005 10:45 am


Tom,

Might this be a carbon arc lamp? There appears to be no significant vent openings at the top portion required for a combustion lamp.

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Postby Optics » Thu Apr 14, 2005 5:38 am


Island,

An arc lamp would require a much larger lantern. It most likely used an electric incandescent bulb. My guess is that it is from the 1930s time period.
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Postby island » Mon Apr 18, 2005 3:13 pm


This supports Tom's suggestion that this was the type of lamp used on lightships and was electric incondescent of the 1930s period.

From Lightship No. 87 "Ambrose"
National Historic Landmark Study
http://www.cr.nps.gov/maritime/nhl/ltship87.htm

"The original kerosene lights had a range of nine miles. In 1920 the vessel was the first lightship to be electrified with carbon-arc lights, increasing the range to 15 miles. The last major alteration to the lights occurred in the early 1930s, when a 1,000-watt light in a 375-mm, cut-glass, 15,000-candlepower lens (then the standard optic for lightships) was installed atop each mast."
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