I have measured light down to 0.001lx, it=B4s not very difficult,
it uses a photo diode, an OP-Amp, feedback resistor of something around
256M, a small cap, and D/A converter minimum 16bit, may be autoranging
circuit depending what total range you are looking for.
You not only can measure the absolute value, but you can tell the amount
of light received per hour, or xhours.
The secrets are in the sensor arrangement, and may be the diode type.
I can help you with just everything, even with a ready to work device.

Friedel Bruening
Bolivian Instruments
Casilla 4856
Santa Cruz - Bolivia
Phone : 00591-773-92119
Fax : 00591-3-3580572
e-mail : bolinst@cotas.com.bo

At 04:35 a.m. 15/11/01 +0800, you wrote:
>I wish to measure light during the night. I am told that typical levels are
>around 0.1 lux. They want a wide range with good resolution. By the way it
>must be light and cheap! Has anyone got any suggestions? I am trying to
>measure a broad band of visible light that animals are exposed to. The moon
>is also a factor.
>
>TIA
>
>
>Peter
>
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