Re: Lamp as artificial sun?

"KLP" <k_paasch@xxxxxxxxxxx> wrote in message
news:45f45192$0$13978$edfadb0f@xxxxxxxxxxxxxxxxxxxxxxx

Hi all,

I am for a laboratory setup looking for a lamp with a spectrum and intensity
as close to the sun as possible.

I have on different websites found references to HPS lamps mostly used for
plant growth (Cannabis etc. -:)

Has anybody ecperiece with such lamps regarding stability (both spectrum and
intentisty). Recommendations of specific lamps are very welcome!

Your question is very general. I believe Don gave you the best and shortest
answer based on the assumption that you want *both* similar intensity and
spectrum to that of the sun.

For cases where you want either the one or the other, things may vary
considerably. If you want to simulate the sun's UV and IR intensity, Sylvania
and PHILIPS both produce "sunlamps" for general tanning which match the sun's
UV output between 280 and 400nm and which also emit considerable amounts of
skin penetrating IR, such as the MLU-300W, but their spectrum in the visible
is far from "close" to the spectrum of the sun.

Specific arrangements with these lamps can reproduce the sun's UV and IR
output, but not the visible spectrum, so they are not very useful for plants.

On the other hand if you want to simulate just the visible spectrum of the sun
without much attention to UV and IR, there are metal halides with very high
color rendering indexes which can do the job nicely, such as the OSRAM
HQI-T/400W/D, or the Xenon short/long arc lamps which Don mentions or simple
halophosphate fluorescents, although none of them are perfect matches.

For plant growth some manufacturers sell lamps specifically designed to match
the photosynthesis curve, such as the RADIUM HRI-T/400W/Planta.

My suggestion is to avoid HPS lamps for plant growth, since they lack
considerably in the blue part of the visible spectrum, which is a part which
is needed by many plants.

Best regards

Kasper Paasch
--
I.N. Galidakis
http://ioannis.virtualcomposer2000.com/

.

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