On Sep 17, 9:51*pm, "Brenda Ann"
wrote:
"bpnjensen" wrote in message

...
On Sep 17, 3:57 pm, John Smith wrote:

On 9/17/2010 4:45 PM, dave wrote:

...
LEDs don't seem very cost effective, and the energy usage seems
comparable to CFLs.

When LEDs come into mass production, to the extent of CFLs, that will
fix the cost effectiveness ... a good LED consumes 50% the power of a
CFL, or better ... this efficiency is not as advanced as it will be in
the future.

Regards,
JS

I'll buy that - I think LEDs will be ubiquitous in the future, and
will be able to serve almost every need.

I bought some LED spotlights for our back path. Run on three "D" cells, IR
activated by motion sensor. The first time I turned one on, it near blinded
me.. it throws a light path for well over 100'... Batteries are supposed to
last around 2 years.

My only concern with LEDs, and this is partly selfish, is that their
spectra are often very broadband and have strong spikes in the blue-
green region. For an amateur astronomer trying to avoid light
pollution, this presents some problems - astro objects often glow in
this region of the spectrum; human vision in the dark is best in this
region of the spectrum; and eyepiece filters used to control light
pollution usually pass wavelengths in this region of the spectrum.
Consequently, LEDs are in direct conflict with good views of deep-sky
objects, and the glow from these devices are nearly impossible to
overcome using filtration. This was not the case with most other
light devices, excepting things like brilliant blue halogen lamps.
Incandescent light, in particular, is easy to filter, as are many
ordinary fluorescent wavelengths.