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[DSLF] Digest Number 1446

There are 3 messages in this issue.

Topics in this digest:

      1. Wishing upon brigter stars
           From: "sheilds76man" <sheilds76man@yahoo...>
      2. Re: "blue" radiation - incandescent vs. fluorescent
           From: "David Keith" <david.keith@mindspring...>
      3. Re: Re: "blue" radiation - incandescent vs. fluorescent
           From: ctstarwchr@aol...


Message: 1         
   Date: Fri, 10 Sep 2004 20:11:28 -0000
   From: "sheilds76man" <sheilds76man@yahoo...>
Subject: Wishing upon brigter stars

The following was published in Tuesday's (7 Sept.) Denver Post. One 
can go to <www.denverpost.com/Stories> for more info.


Aaron Reid, CO


Message: 2         
   Date: Fri, 10 Sep 2004 15:46:15 -0600
   From: "David Keith" <david.keith@mindspring...>
Subject: Re: "blue" radiation - incandescent vs. fluorescent

G. H wrote:
> Subject: "blue" light - incandescent vs. fluorescent
> OK folks, I finally collected the data on the amount of "blue" in warm
> fluorescent vs. incandescent. All of the information is from Osram
> .....
> I have all the data that I can send to someone, or post if Cliff tells
> me how to do that.

I would be interested in getting the "warm fluorescent" SPD information -
please email to david.keith@mindspring...

I have been working with SPD's - from CIE and Philips, for incandescent,
daylight, MH, HPS and fluorescent - evaluating radiation from 464-484 nm per
the action spectrum reported by Bud Brainerd et al and cited in Dr. Pauley's
paper.  My results are very consistent with the numbers in G.H.'s message -
that incandescent is quite a bit higher than the 3000K fluorescent SPD I
have - and that the trend over fluorescent is such that 2700K should be even

For 464-484 nm, based on 100 lms, I have the CIE source A (incandescent at
2756K as I recall) with 0.013 W total (average of 0.61 milliW/nm over the
21-nm-wide band) vs F30 with 0.005 W total (average of 0.22 milliW/nm).
This compares with MH at 0.022 to 0.017 W total (average of 0.91 milliW/nm)
and F65 at 0.020 W total (average of 0.96 milliW/nm)!

I am trying to finish up the summary of this analysis and both put it on the
web and take it to the IESNA Street and Area Lighting Conference this month.
I will post the URL when it is set.

I would note that the "currently understood" action spectrum is 464-484 -
not 440-480 as previously reported - and that the sensitivity function over
that band (or the remainder of the EM) is not "known" - but that evaluations
of the energy between 464-484 nm is an appropriate first step.  Furthermore
it is not "light" that is of interest but radiation - the use of the term
light implies the use of a visual sensitivity function, which is clearly
wrong in this case.

David Keith, FIES


Message: 3         
   Date: Fri, 10 Sep 2004 18:58:20 EDT
   From: ctstarwchr@aol...
Subject: Re: Re: "blue" radiation - incandescent vs. fluorescent

In a message dated 9/10/2004 5:56:54 PM Eastern Daylight Time, 
david.keith@mindspring... writes:

> Furthermore it is not "light" that is of interest but radiation - the
> use of the term light implies the use of a visual sensitivity function,
> which is clearly wrong in this case.


Pardon what might seem like a ridiculous question, but if *radiation* 
within the electromagnetic spectrum falling between 380 nm and 700 nm 
is no longer universally considered to be *visible light* by ISO 
Standards promulgated by both the IES and the CIE then what the heck 
is it?  I wonder if it might be a dark (or health) sucker instead?  ;-)


All kidding aside, I know what you are trying to convey, but if it 
travels at the speed of *light* and it is technically classified by 
international standards as *optical radiation* when falling within 
that range of electromagnetic radiation then why call it something 
else to confuse people?  I'm sure the ganglion cells in our retinas 
don't care what we call it and the results will be the same as the 
mounting piles of scientific research are now starting to prove.  I 
have advocated the researchers use luminance opposed to illuminance 
for the past couple of years, but I think you're onto something with 
radiometry opposed to photometry in this particular case.

As I understand it, this spectral range is BOTH radiation AND it is 
light.  It is great you are in contact with Bud Brainard, but he is 
not the only clock doc working on this issue of how light, optical 
radiation, luminous goo or whatever else anyone chooses to call it 
when mismanaged inappropriately by the current practice is proving 
to be a harmful negative stimulus that may have very serious effects 
on our health and the environment as a whole, though Bud does seem to 
be the most conservative of them all.  Let's look at the whole picture.

We cannot ignore other notable scientists like Russ Reitter, Richard
Stevens, David Blask, and many other professional researchers on
the cutting edge of these new and quite disconcerting discoveries.  


The industry needs to recognize and respect that rather than striving 
with any possible means at their disposal to protect their status quo 
of obsolete and obscenely Bohemian outdoor lighting practices.  I say
that because of the recent article published by the LRC.  New evidence 
the continuing research has discovered is surfacing on a monthly basis 
and we have an obligation to learn as much as we can from it IMHO, not
use old data that may be inconclusive but is comforting to make a point.
Some of the LRC justifications were based on decade old research.

Back to the theories of radiometry versus photometry, would it be 
possible for you to provide any insight on why the data that Glen 
received included the */1000 lumens* metric in the spectral data? 
I could not find any references to that last part of the metric 
relating to spectral radiation in my IES literature (IES Lighting 
Handbook 9th Edition and others), but maybe I missed it.  My guess 
is maybe to express the value in milliwatts per nanometer of unit 
wavelength in radiant output (not power input) perhaps?

Glen, thanks for following up on getting that data so we could learn
more.  All light sources have some degree of blue lumens unless they 
are HPS or LEDs, so best precautionary principle I can think of might
be to apply fully shielded lighting at the lowest possible levels.  
It worked for the major part of the century until HID became popular.

Please forward the data you wish to share as a file attachment sent
to:  darksky-list-owner@yahoogroups... so the DSLF Moderators can 
all receive copies and place it in either the photos or the files 
section of DSLF.  One of us will send an announcement to the group 
indicating where it can be downloaded after that.  Thanks!

Clear skies and good seeing,
Keep looking up!

Cliff Haas
Author Light Pollution Awareness Website (LiPAW)


[Non-text portions of this message have been removed]


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