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post #33 of (permalink) Old 03-18-2013, 04:39 PM
No more Bow ties
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Join Date: Dec 2006
Location: Cincinnati
Posts: 15,510
Originally Posted by Wasserpest View Post
Is there a direct relationship between Lumen and PAR? I am not an expert, but I thought they are two different units, and things like spectrum play a role? Like having two LEDs with the same luminous flow, one with peaks in the yellow/green area, another one more in the red/blue photosynthetically speaking more significant area ?
Yes on all the questions. On Apogee's site there is a lumens to par conversion equation. There is a relationship but it's an approximation for white sun light. A par sensor will have a peak toward the blue.

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