what does this figure at 1 meter

like most lights here are rated ?
can anybody do the math real quick?
just curious, thanks http://www.spectrolab.com/searchlights/pdfs/SX-16 ENH 020910 REV C.pdf

hahoo said:

like most lights here are rated ?
can anybody do the math real quick?
just curious, thanks http://www.spectrolab.com/searchlights/pdfs/SX-16 ENH 020910 REV C.pdf

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40 million CD min, 50 million CD nominal as spec'ed
divide each by 1 million gives 40 lux and 50 lux, respectively @ 1km, but spec'ed is only 32 lux.

scs said:

40 million CD min, 50 million CD nominal as spec'ed
divide each by 1 million gives 40 lux and 50 lux, respectively @ 1km, but spec'ed is only 32 lux.

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yeah , i saw that, but how do you get it down to what it is at 1 meter ?

hahoo said:

yeah , i saw that, but how do you get it down to what it is at 1 meter ?

Click to expand...

CD is typically spec'ed @ 1m.

scs said:

40 million CD min, 50 million CD nominal as spec'ed
divide each by 1 million gives 40 lux and 50 lux, respectively @ 1km, but spec'ed is only 32 lux.

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At 1km, the atmosphere is going to absorb and scatter a lot of light, so perhaps that's why it's spec'd lower.

WalkIntoTheLight said:

At 1km, the atmosphere is going to absorb and scatter a lot of light, so perhaps that's why it's spec'd lower.

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Good point. thanks.

So you're trying to say, Beijing atmosphere is different than L.A. atmosphere?

Parrot Quack said:

So you're trying to say, Beijing atmosphere is different than L.A. atmosphere?

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Both are pretty bad, but I suspect you couldn't even get a 100 watt laser through 1km of Beijing smog! :sick2:

WalkIntoTheLight said:

Both are pretty bad, but I suspect you couldn't even get a 100 watt laser through 1km of Beijing smog! :sick2:

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Beijing smog.



This is cut-n-paste, not hot linked.

so nobody knows ?

scs posted an answer/reply in post number #4. As to the accuracy of his reply, that I can't say.

scs said:

CD is typically spec'ed @ 1m.

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so how to figure back to .25 lux, from 32 lux?
thats the number im looking for

hahoo said:

so how to figure back to .25 lux, from 32 lux?
thats the number im looking for

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The formula is CD (@1m) divided by the square of distance (meters squared) equals lux at the distance.

The empirical measurement given is 32 lux @ 1km. Based on the formula above, that means the CD @ 1m equals 32 times (1000m) squared, in other words, 32 million CD.

take 32 million, divide that by 0.25 lux, and then take the square root of the quotient, and you get the correponding theoretical throw distance in meters.

2828 meters.....
not too shabby
thought it would be way more though
my modded tk61 does like 1600 or 1700 meters