Re: Light output of dimmed lamps

In <slrndr145v.iha.don@xxxxxxxxxxxxxx>, I, Don Klipstein wrote in part:

(A first and "very low side" "calculation" of minimum illumination to
see at all, in part:)

> A surface 1 meter away would have a piece 8.73 mm wide appear half a
>degree wide. And 1 photon out of every 40,000 emitted would pass through
>an effectively 10 mm diameter pupil from that distance. 200,000 photons
>per second from a square 8.73 mm wide is about 26.2 million photons per
>second emitted per square meter.

I forgot to multiply that 40,000 by 5 twice - to get 5 photons through
the pupil per .2 second. Multiply everything by 5 to correct.

>...
>so now my rough "first calculation" becomes 33.5 picowatts per square
>centimeter.

Now it's .16 nanowatt per square meter.

This still sounds awfully low and not just a little lower than the
second and third "calculations" that ended up close together in
"determination" and I suspect something could still be wrong.

><SNIP>

> If that 33.5 picowatt per square centimeter figure I got at first
>has any truth to it, then surface brightness would be 2.7E-13 candela per
>square centimeter. A blackbody achieves this at about 521 Kelvin.

Changes to 542 Kelvin, and this "low side" could still be too low. The
second figure of 687 Kelvin and the third figure of 702 Kelvin stay the
same.

> These temperatures are for calculating for photopic vision. Since
>scotopic vision requires shorter wavelengths than photopic vision does,
>the temperature required to make a blackbody visibly glow would be a
>little higher than these temperature figures.

- Don Klipstein (don@xxxxxxxxx)
.

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