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[DSLF] Digest Number 871
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------------------------------------------------------------------------
There are 12 messages in this issue.
Topics in this digest:
1. Re: FCO streetlight costs vs. regulare Cobra head
From: Steve Davis <w2sgd@juno...>
2. Compare FCO to Fully-shielded
From: "Laverne Booth" <ljbooth@thevine...>
3. Capturing light in pictures
From: ctstarwchr@aol...
4. Re: FCO vs. Drop Lens
From: Gary Citro <callisto@optonline...>
5. Re: FCO streetlight costs vs. regulare Cobra head
From: "ctstarwchr <ctstarwchr@aol...>" <ctstarwchr@aol...>
6. Now
From: Steve Davis <w2sgd@juno...>
7. Re: Re: FCO vs. Drop Lens
From: "James Benya" <jbenya@benyalighting...>
8. Re: Compare FCO to Fully-shielded
From: "James Benya" <jbenya@benyalighting...>
9. Re: FCO vs. Drop Lens
From: ctstarwchr@aol...
10. Re: Re: FCO vs. Drop Lens
From: Yvan Dutil <yvan.dutil@sympatico...>
11. Re: Re: bulbs with lampshades?
From: "Karolyn Beebe" <keedo@merr...>
12. Re: Now
From: Steve Davis <w2sgd@juno...>
________________________________________________________________________
________________________________________________________________________
Message: 1
Date: Sat, 14 Dec 2002 11:06:11 -0500
From: Steve Davis <w2sgd@juno...>
Subject: Re: FCO streetlight costs vs. regulare Cobra head
Cliff,
As for meeting ANSI RP-8-00, union guys from the utility
company running around in bucket trucks don't qualify as lighting
designers when they follow seat-of-the pants, every other
pole - maybe - criteria with lights pointing every which way
which hasn't cut off any federal highway funding. Power
company salesmen and "specialists" don't qualify either.
Neither do mayors and members of local governing boards.
Your arguments are purely academic.
As for the M400, you missed one. Also, the M400 is a big,
no holds barred, road blaster so lighting control for LT is not
much of a factor. -sd
________________________________________________________________
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Message: 2
Date: Sat, 14 Dec 2002 08:46:41 -0500
From: "Laverne Booth" <ljbooth@thevine...>
Subject: Compare FCO to Fully-shielded
Jim, in one of your recent emails (I'm sorry I didn't save it), you made a statement to the effect that full-cutoff and fully-shielded are NOT the same. I know how both terms are defined in RP-33-99, but I need a good, simple explanation that I could use when talking with city council, planning and zoning, concerned citizens, etc. Help?
-Laverne Booth
Hesperia, CA
[Non-text portions of this message have been removed]
________________________________________________________________________
________________________________________________________________________
Message: 3
Date: Sat, 14 Dec 2002 11:08:08 EST
From: ctstarwchr@aol...
Subject: Capturing light in pictures
For people interested in photographing both good and obtrusive lighting, a
master shares some of his secrets in an article about balancing contrast of a
scene to get an inviting appearance. Shooting at or near dusk often delivers
the best results opposed to taking images long after the sky darkens because
there is more ambient light to brighten darker areas not directly
illuminated. Those areas are visible to the eye perhaps due to multiple
levels of adaptation but not to the camera.
This fellow is a remarkable artist who carefully applies additional fill
lighting not part of the lighting system when necessary to balance the high
contrast areas into a warm and even inviting scene. The glare from
unshielded fixtures is tamed by this technique, however. One of our noteables
serving as an enabler gets a great mention in this article, too! :-)
> PHOTOGRAPHER SHEDS LIGHT ON CAPTURING LIGHT IN PICTURES
>
> Doug Salin is a San Francisco-based photographer who specializes in
> making lighting projects shine. Lighting.com talks to Doug about how
> he composes a photograph, what the challenges are in "lighting"
> lighting projects, and more.
>
> Read More
> http://www.lighting.com/index.taf?_&_sn=content&_pn=story&_op=439
The IDA website has a good information sheet offering tips on photographing
lights at night by using a 35 mm SLR with slide or emulsion film. When using
a digital (Olympus D-380) I set the camera for night shots, which engages the
flash with a 1 second exposure at f/4 and an ASA 400 simulation. To prevent
fill light from the flash I cover the built in flash lens with black
electrical tape and use the timed exposure option with the camera on a tripod
to reduce the shake that causes blurry images. I also try to shield any
light from shining on the lens face from adjacent fixtures above or to the
sides. This helps to reduce coma effects in the images that are not visible
in the view finder. It works fairly well after dark but still could stand
improvement. It would be nice to have longer exposure times, but 1 second is
the maximum my camera offers. Experimenting with photographic gels can offer
good filtering effects to balance colors closer to what the eye sees without
need of a retouch afterwards. Rosco offers some excellent gels often
available at well stocked photographic supply stores.
http://www.rosco.com
You can also use diffraction gratings available from Edmund Scientific to
capture the spectral frequency of various lamp types. What techniques work
well for you and what kind of camera do you use? Your tips and tricks shared
with the group may help us all get better results and encourage many others
to experiment.
Clear skies and good seeing,
Keep looking up!
Cliff Haas
Author: Light Pollution Awareness Website (LiPAW)
http://members.aol.com/ctstarwchr/index.htm
Fight for your right to see stars in the night!
Join IDA Today! http://www.darksky.org
[Non-text portions of this message have been removed]
________________________________________________________________________
________________________________________________________________________
Message: 4
Date: Sat, 14 Dec 2002 11:35:38 -0500
From: Gary Citro <callisto@optonline...>
Subject: Re: FCO vs. Drop Lens
Jim Benya wrote:
<<Your comments about "ignoring photobiology and the
capabilities of the human eye..." are not clear - but let me repeat, my work
for IDA on the MLO follows the IDA position statement on photobiology and
the capabilities of the human eye. If you have a problem with that, please
address your comments to Dr. Crawford.<<
OK, there's an IDeA.
On that note, I have tried unsuccessfully to find the "IDA position
statement on photobiology and
the capabilities of the human eye" even through a search of the site. Can
you help me out there?
One thing I did find was "IDA's Position on Lighting Ordinances":
http://www.darksky.org/ordsregs/positionlo.html
which I actually found pretty alarming, particularly the last 2 paragraphs.
I wonder if the nearly 10,000 members of the IDA are in agreement that we
should all be waiting until the MLO is completed before we try to enact
local ordinances, and not use any of the existing examples already in place
and working well??!!!
>From my experience, the "lighting professionals" where I live don't seem to
be qualified AT ALL to assist in the development of light pollution
*reduction* ordinances. In fact, despite our best good faith educative and
political efforts, I've seen more acorns and garbage lighting go up in the
last few years than ever before.
If we had a LAW, like the Hailey, the Ketchum, or *something* with teeth in
place here when I first got into this, my area would be much better off. I
support the development of a light pollution reducing MLO, but while it is
being developed I see no reason not to push for the best of what we already
have, which might even be better in the end.
Waiting for "the industry" to protect us doesn't seem to work where I live
when it comes to almost any environmental issue.
Gary Citro
________________________________________________________________________
________________________________________________________________________
Message: 5
Date: Sat, 14 Dec 2002 17:34:29 -0000
From: "ctstarwchr <ctstarwchr@aol...>" <ctstarwchr@aol...>
Subject: Re: FCO streetlight costs vs. regulare Cobra head
--- In DarkSky-list@yahoogroups..., Steve Davis <w2sgd@j.....> wrote:
>
> As for meeting ANSI RP-8-00, union guys from the utility
> company running around in bucket trucks don't qualify as lighting
> designers when they follow seat-of-the pants, every other
> pole - maybe - criteria with lights pointing every which way
> which hasn't cut off any federal highway funding. Power
> company salesmen and "specialists" don't qualify either.
> Neither do mayors and members of local governing boards.
> Your arguments are purely academic.
You're right about the union guys and local officials Steve, but not
about RP-8. Meeting RP-8-00 is not up to those union guys, it is up
to the DESIGNER to develop comprehensive plans so the crews in the
bucket trucks with pole augers can understand and apply. The problem
is that MANY designers think they can pick and choose criteria at
will in ala carte fashion without using ALL metrics in a given design
method while still claiming minimums for RP-8-00 have been met in
their designs. That is fundamentally wrong and technically incorrect
not to mention plain bad practice. Adding to that, RP-8 includes, on
page 11, two paragraphs clearly statinging this practice is not
acceptable, too!
I have quite a bit of experience chasing bucket trucks in efforts to
affect reform. In 1999 afer driving 350 miles of state roads in CT
to log how many flat lens cobras could be found I only discovered a
total of 8 out of thousands of semi-cutoffs. CT established State
Statute 13a-110a in 1996 requiring full cutoff lighting to be used on
all state funded roads. I saw those 8 fixtures installed over a
period of 3 years as being an egregious disregard for the law, so I
called in the Attorney General to do an investigation which he did,
and within a month, FCO luminaires started popping up along state
routes in many places. Neither DOT nor the utility companies had
ever been made aware the law existed by an official state agency. Go
figure, but take it as a valuable lesson to assure code is written
into any state law providing requirements on how to disseminate the
information for the best results. None currently do this.
Also, I carried stacks of copies of the law in my car and would pass
them out to the utility crews parked along state roads and speak with
them about lighting they were working on. Once I hit the jackpot and
got 30 in one shot before they hit the roads while they were going
over the plans for the day! In favor of your statement above, the
most interesting reply I ever got when asking, "Do you know what full
cutoff luminaires are?" came from a lineman who had been installing
roadway lights every day for over 30 years. He believed that a full
cutoff luminaire, "cut the power off when someone hit a utility
pole!" AAARRRRGGGGGH!!??!! Trying hard not to laugh I patiently
explained, "No, they are the ones with flat lenses not the dropped
bowl shaped lenses," and I asked if he had ever installed or had seen
any back at the supply shed. The answer was no and none existed at
the supply shed, but he had seen one installed on a pole. He could
not recall where it was though. I ended up getting back a copy of my
business card a few weeks later from the utility company. The guy
went to his boss and also sent copies of the state law to the NU
headquarters in Mass. I was intrigued that such a simple effort
along the roadside traveled that far and as time passed more FCOs
continued to pop up all over the place.
> As for the M400, you missed one. Also, the M400 is a big,
> no holds barred, road blaster so lighting control for LT is not
> much of a factor.
Nothing was missed at all. You're just bringing moots into the
equation. The fact remains, with the GE M400 (not a cheap knock-
off), the flat glass lens is directly interchangeable with the semi-
cutoff refractor BECAUSE they use the same reflector. However, the
socket position of the lamp must be changed (raised) to one of the 18
other possible locations depending on desired photometric
performance. The GE M400 EVEN comes packaged with instructions on
how to do it, and that's pretty cool in my book. The M400 Cutoff is
one FCO that works excellent for light pollution control WITHOUT
reducing pole spacing when mounted at and over 39 feet high in many
(but not all) large road applications. It is not the most
appropriate for most municipal use, especially in residential areas.
Clear skies,
Cliff Haas
http://members.aol.com/ctstarwchr
________________________________________________________________________
________________________________________________________________________
Message: 6
Date: Sat, 14 Dec 2002 12:15:44 -0500
From: Steve Davis <w2sgd@juno...>
Subject: Now
Mark your calendar for the PBS program "NOW" with Bill Moyers,
"The Environment in the Supreme Court". If you check <pbs.org>,
there is stuff on global warming and sustainable environment.
This show is so popular that the local station had to suspend
its fund raising or face a viewer revolt.
Maybe they would consider a program on LP if enough people
were to write connecting the dots? -sd
________________________________________________________________
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________________________________________________________________________
Message: 7
Date: Sat, 14 Dec 2002 09:56:54 -0800
From: "James Benya" <jbenya@benyalighting...>
Subject: Re: Re: FCO vs. Drop Lens
ABOUT LIGHT AND PHOTOBIOLOGY
The IDA position has been stated by Dr. Crawford on several occasions. I
was making this point because Steve Davis, Steve Pauley and others
periodically introduce human health and photobiology into the discussions
here, and I wanted to make it clear that the MLO work will take whatever the
official IDA position is. We are all very excited about the latest findings
by Bud Brainard and others about human photobiological response, and many of
us think that some day there will be compelling science to support
relatively radical restrictions to outdoor lighting. However, some
contributors to this forum want to leap to conclusions about serious health
consequences caused by unwanted light. The IDA's official position is that
the science is not sufficiently conclusive and we can't make this step.
We continue to develop the MLO because there are many good environmental
reasons as well as reasons of common sense and interest in astronomy.
NEEDING A LAW NOW
It is my experience that government agencies are LOATHE to change a law once
enacted, especially a law that involves a number of public hearings and ties
up the city council's agenda for a period of six months or more. Once they
do it, they will want to move on to other things. When a poorly written law
is enacted, it stays on the books for years.
If you "roll your own", you isolate yourself from what we are trying to
organize, which is an international movement for everyone to adopt the same
ordinance. In my vision, we create a broadly accepted, competent ordinance
(or two) for which we can develop supporting literature, and then use the
combined and orchestrated efforts of thousands of volunteers at the grass
roots level to get the MLO accepted everywhere. Then, we can teach MLO
compliance classes to city planners and engineers, and we can teach MLO
design classes to municipal engineers, planners, architects, etc. Finally,
we can teach MLO principles to electricians so that the very people who
install the lighting help us enforce it.
I know this will work and we are doing as much as we can with volunteer
labor. I have spent almost a month's worth of professional time this year
on the MLO and IDA matters - like you and others' efforts, it is all
volunteer. We are trying to get a grant that could help us speed this up,
allowing the IDA to hire people to carry this effort forward, but even THAT
takes volunteer time. We are working as fast as we can - your support would
be appreciated.
James R. Benya, PE, FIES, IALD, LC
Benya Lighting Design
1880 Willamette Falls Drive
Suite 220
West Linn, OR 97068
(503) 657-9157 cell (503) 519-9631
Fax (503) 657-9153
----- Original Message -----
From: "Gary Citro" <callisto@optonline...>
To: "Dark-Sky Mailing List" <DarkSky-list@yahoogroups...>
Sent: Saturday, December 14, 2002 8:35 AM
Subject: [DSLF] Re: FCO vs. Drop Lens
> Jim Benya wrote:
> <<Your comments about "ignoring photobiology and the
> capabilities of the human eye..." are not clear - but let me repeat, my
work
> for IDA on the MLO follows the IDA position statement on photobiology and
> the capabilities of the human eye. If you have a problem with that,
please
> address your comments to Dr. Crawford.<<
>
> OK, there's an IDeA.
> On that note, I have tried unsuccessfully to find the "IDA position
> statement on photobiology and
> the capabilities of the human eye" even through a search of the site. Can
> you help me out there?
>
> One thing I did find was "IDA's Position on Lighting Ordinances":
> http://www.darksky.org/ordsregs/positionlo.html
> which I actually found pretty alarming, particularly the last 2
paragraphs.
>
> I wonder if the nearly 10,000 members of the IDA are in agreement that we
> should all be waiting until the MLO is completed before we try to enact
> local ordinances, and not use any of the existing examples already in
place
> and working well??!!!
> From my experience, the "lighting professionals" where I live don't seem
to
> be qualified AT ALL to assist in the development of light pollution
> *reduction* ordinances. In fact, despite our best good faith educative
and
> political efforts, I've seen more acorns and garbage lighting go up in the
> last few years than ever before.
> If we had a LAW, like the Hailey, the Ketchum, or *something* with teeth
in
> place here when I first got into this, my area would be much better off.
I
> support the development of a light pollution reducing MLO, but while it is
> being developed I see no reason not to push for the best of what we
already
> have, which might even be better in the end.
> Waiting for "the industry" to protect us doesn't seem to work where I live
> when it comes to almost any environmental issue.
>
> Gary Citro
>
>
>
________________________________________________________________________
________________________________________________________________________
Message: 8
Date: Sat, 14 Dec 2002 11:45:49 -0800
From: "James Benya" <jbenya@benyalighting...>
Subject: Re: Compare FCO to Fully-shielded
For your purposes, the concepts are simple. The INTENT of the concept is two primary things:
1. Sky glow is caused in part by light emitted from a luminaire above the horizontal plane. This light is purely wasted energy and serves no good purpose. Most lighting ordinances should ban luminaires that emit light upwards, with exceptions for a few styles of luminaires under very limited conditions.
2. Light trespass is light which "trespasses" onto adjacent properties, which is a nuisance and can be very objectionable. This light is also waste because it is not lighting the intended area. Most lighting ordinances should ban light trespass, except perhaps from adjoining commercial properties.
Now the confusing part:
The most objectionable light causing trespass is light emitted just below the horizontal, roughly elevated between 75 and 90 degrees relative to nadir (straight down). To many dark sky advocates, light trespass prevention is as important as reducing sky glow. Since most dark sky advocates are familiar with the term "full cut off", many expect that it will address both forms of light pollution.
However, roadway lighting engineers histroically have used light in the 65-75 degree region to improve uniformity of roadway light, and inevitably, this can cause increased emissions in the 80-90 degree range and sometimes above 90 degrees. Thus they designated luminaires with a little upward emission and considerable 80-90 degree emission "cut off" and luminaires with more upward emission and 80-90 degree emission"semi cut off".
For many reasons, the definitions given above are NOT GOOD ENOUGH. The IESNA has created a committee to re-state the definitions of cut-off, etc. The committee is in progress, meanwhile the industry is in limbo.
Meanwhile, "shielded" has been used as an alternative expression. The IDA uses it as part of the Outdoor Lighting Code Handbook in order to make the concept simpler and easier to understand by lay persons. Shielded means that light is prevented from upwards emission, but there is less concern over candlepower distribution as compared to the IESNA "cutoff" designations.
The MLO working group is anxiously awaiting the IESNA because laws should be technically measurable and accurate. In the meantime, I hope this helps.
James R. Benya, PE, FIES, IALD, LC
Benya Lighting Design
1880 Willamette Falls Drive
Suite 220
West Linn, OR 97068
(503) 657-9157 cell (503) 519-9631
Fax (503) 657-9153
----- Original Message -----
From: "Laverne Booth" <ljbooth@thevine...>
To: "Benya, Jim" <benya@attbi...>; "DarkSky-list" <DarkSky-list@yahoogroups...>
Sent: Saturday, December 14, 2002 5:46 AM
Subject: [DSLF] Compare FCO to Fully-shielded
> Jim, in one of your recent emails (I'm sorry I didn't save it), you made a statement to the effect that full-cutoff and fully-shielded are NOT the same. I know how both terms are defined in RP-33-99, but I need a good, simple explanation that I could use when talking with city council, planning and zoning, concerned citizens, etc. Help?
> -Laverne Booth
> Hesperia, CA
>
>
>
[Non-text portions of this message have been removed]
________________________________________________________________________
________________________________________________________________________
Message: 9
Date: Sat, 14 Dec 2002 15:36:56 EST
From: ctstarwchr@aol...
Subject: Re: FCO vs. Drop Lens
Greetings:
With all of my years of tedious research I've never found anything on this
subject. Does anyone know of any true scientific studies that have published
peer reviewed papers that accurately assessed the impact of what happens
above various different cutoff types of luminaires in their immediate
proximity? The Smart Road VDOT continues to develop between Blacksburg and
Christiansburg, Virginia would be the only place this type of study could be
performed in a controlled environment that is relatively far away from major
skyglow.
The overall negative impact of semi-cutoff and cutoff fixtures is extremely
difficult to quantify or assume accurately based on the 2-1/2 or 5% factor
allowed for emission angles at and above the horizontal plane because the
photometric report vertical intensity emission data terminates at 90 degrees
in many if not most cases of LM-63 Type C photometry -- even with noncutoff
luminaires.
The Smart Road is capable of reproducing any weather condition which means it
should be able to create fog! This capability offers an unparalleled
opportunity for researchers who can apply for time to study when coupled with
the amazing analysis power of a wide range dynamic radiometer to accurately
quantify how much light is truly scattered at low angles above the
horizontal.
http://www.virginiadot.org/projects/constsal-smartrdoverview.asp
And...
http://www.biospherical.com/products/wlr-2800.pdf
With the current mission of IESNA to redefine the terms of cutoff that will
be applied to the lighting industry including manufacturers I do hope the
following is considered.
Task lighting area is obviously of the greatest concern, however, wasted
energy in the form of light spilling to areas where it is neither useful nor
desired needs to be another. Here's where the night sky and light trespass
comes into play... Unless the engineers developing the new criterion also
take all Rayleigh and MIE scattering effects into account as well as factors
for absorption, refraction, and reflection characteristics of airborne
aerosols, and absorbent solids like soot and dust, it is very unlikely that
the assumptions of low impact from candela emissions in these zonal areas at
and above the horizontal are accurate. In a vacuum these would of course be
totally valid assumptions, but probably not nearly as accurate when direct
light emissions interact with those other very powerful and important factors
that cause light to radiate back to Earth from the sky caused by light coming
from the ground. Peer reviewed and published scientific research has clearly
indicated that the reflected light sent skyward from the ground is not nearly
as damaging to the sky as direct emissions near and above the horizontal are.
Evaluating a string of luminaires in a foggy environment where the sensor is
placed at various heights above the point of opacity on the luminaires'
housings might reveal some very intriguing information that nobody has ever
truly quantified in a scientific manner before outside of sticking a
luminaire into the interior of a goniophotometer with a relatively inert and
well controlled atmosphere.
Yes, many studies have been done of the results of both reflected and direct
skyward emissions around cities and far away from cities, but nobody has ever
taken it to the source level and measured radiance of the air at near 100%
humidity within close proximity to the luminaires themselves. Water droplets
small enough to remain airborne each form a sphere due to their own gravity
and surface tension. Therefore, very little absorption caused by impurities
like dust and soot might be likely to occur due to their refractive and
reflective powers.
This sounds to me like it might be a viable subject that is both scientific
enough and also beneficial enough for IDA or the IESNA or both to seek a
study grant from NSF or even various luminaire manufacturers to explore it.
After all, most photometric study reports of luminaires by the industry have
historically only considered how to improve light sent to intended target
areas and therefore may be one reason why most goniophotometer reports do not
evaluate anything above 90 degrees unless specifically requested to do so by
the manufacturer paying the bill for the report to be done.
It is amazing how a very small amount of light emitting above the horizontal
can travel great distances without deteriorating in visibility when the
reflective, magnification, and refractive powers of water droplets enter the
equation. Only evaluation of MIE scattering can address that on paper, but
when also adding gaseous aerosols where Rayleigh scatter comes into play it
compounds the problem even more, especially with the blue and green rich
frequencies of mercury vapor and metal halide lighting.
Food for thought I hope IDA feasts on. These data could allow assessing
*total* upward waste that could be applied to a $ sign at the luminaire.
That could benefit manufacturers in marketing literature (our fixture wastes
less light) and customer desires (we want more efficient use for our $) as
much as it could benefit dark sky advocates striving in their efforts to
affect reform as well. It sure would be nice to be able to say, "this type
of fixture generally puts 99.5% of its light where it belongs and we should
be using them to save energy."
Clear skies and good seeing,
Keep looking up!
Cliff Haas
Author: Light Pollution Awareness Website (LiPAW)
http://members.aol.com/ctstarwchr/index.htm
Fight for your right to see stars in the night!
Join IDA Today! http://www.darksky.org
[Non-text portions of this message have been removed]
________________________________________________________________________
________________________________________________________________________
Message: 10
Date: Sat, 14 Dec 2002 20:51:25 -0500
From: Yvan Dutil <yvan.dutil@sympatico...>
Subject: Re: Re: FCO vs. Drop Lens
Cliff, I am just working on this issue right now as about to complete my paper.
To say the true, the motto zero light above the horizon is true within a fraction
of a percent. The problem as you said it that nobody can garenteed that. Even
little dust on the optic and the ULOR gows from 1% to 3%! I if you add the margin
for misalignment, they goes to zero. As for foggy situaton the answer is quite
straitforward to calculation: the final light distribution will be perfectely
symetrical.
Yvan Dutil
ctstarwchr@aol... a écrit :
>
> Task lighting area is obviously of the greatest concern, however, wasted
> energy in the form of light spilling to areas where it is neither useful nor
> desired needs to be another. Here's where the night sky and light trespass
> comes into play... Unless the engineers developing the new criterion also
> take all Rayleigh and MIE scattering effects into account as well as factors
> for absorption, refraction, and reflection characteristics of airborne
> aerosols, and absorbent solids like soot and dust, it is very unlikely that
> the assumptions of low impact from candela emissions in these zonal areas at
> and above the horizontal are accurate. In a vacuum these would of course be
> totally valid assumptions, but probably not nearly as accurate when direct
> light emissions interact with those other very powerful and important factors
> that cause light to radiate back to Earth from the sky caused by light coming
> from the ground. Peer reviewed and published scientific research has clearly
> indicated that the reflected light sent skyward from the ground is not nearly
> as damaging to the sky as direct emissions near and above the horizontal are.
>
> Evaluating a string of luminaires in a foggy environment where the sensor is
> placed at various heights above the point of opacity on the luminaires'
> housings might reveal some very intriguing information that nobody has ever
> truly quantified in a scientific manner before outside of sticking a
> luminaire into the interior of a goniophotometer with a relatively inert and
> well controlled atmosphere.
>
> Yes, many studies have been done of the results of both reflected and direct
> skyward emissions around cities and far away from cities, but nobody has ever
> taken it to the source level and measured radiance of the air at near 100%
> humidity within close proximity to the luminaires themselves. Water droplets
> small enough to remain airborne each form a sphere due to their own gravity
> and surface tension. Therefore, very little absorption caused by impurities
> like dust and soot might be likely to occur due to their refractive and
> reflective powers.
>
> This sounds to me like it might be a viable subject that is both scientific
> enough and also beneficial enough for IDA or the IESNA or both to seek a
> study grant from NSF or even various luminaire manufacturers to explore it.
> After all, most photometric study reports of luminaires by the industry have
> historically only considered how to improve light sent to intended target
> areas and therefore may be one reason why most goniophotometer reports do not
> evaluate anything above 90 degrees unless specifically requested to do so by
> the manufacturer paying the bill for the report to be done.
>
> It is amazing how a very small amount of light emitting above the horizontal
> can travel great distances without deteriorating in visibility when the
> reflective, magnification, and refractive powers of water droplets enter the
> equation. Only evaluation of MIE scattering can address that on paper, but
> when also adding gaseous aerosols where Rayleigh scatter comes into play it
> compounds the problem even more, especially with the blue and green rich
> frequencies of mercury vapor and metal halide lighting.
>
> Food for thought I hope IDA feasts on. These data could allow assessing
> *total* upward waste that could be applied to a $ sign at the luminaire.
> That could benefit manufacturers in marketing literature (our fixture wastes
> less light) and customer desires (we want more efficient use for our $) as
> much as it could benefit dark sky advocates striving in their efforts to
> affect reform as well. It sure would be nice to be able to say, "this type
> of fixture generally puts 99.5% of its light where it belongs and we should
> be using them to save energy."
>
> Clear skies and good seeing,
> Keep looking up!
>
> Cliff Haas
> Author: Light Pollution Awareness Website (LiPAW)
> http://members.aol.com/ctstarwchr/index.htm
>
> Fight for your right to see stars in the night!
> Join IDA Today! http://www.darksky.org
>
> [Non-text portions of this message have been removed]
>
> _________________________________________________
> To subscribe to the DarkSky List Forum send email
> to: DarkSky-list-subscribe@yahoogroups... or visit:
>
> http://groups.yahoo.com/group/DarkSky-list/join
>
> Help save your town from obtrusive lighting --
> Invite your Planning and Zoning department and
> local officials to join us! Please visit the IDA
> website at http://www.darksky.org frequently, too!
>
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Message: 11
Date: Sat, 14 Dec 2002 19:52:22 -0600
From: "Karolyn Beebe" <keedo@merr...>
Subject: Re: Re: bulbs with lampshades?
Thanks gentlemen, I've seen those cones in some
modern designs, but they're a lot bigger. Looks like
they reflect light up. Still like the lampshade idea
though, in the 'carriage lamp' on a post in a nearby yard
(top too small for extending the bulb into). Not on the
bulb, but suspended over it, attached to the top with a
strap or chain..
Just tried it with paper.. cut a disk; cut it to the middle;
made a parallel cut to make a strap; turned the disk into
a cone. The flare could be adjusted for the situation -
this one should light the walkway, steps and porch, but
the post is tall enough to make that easy.
I'll get back with results.
Karolyn - Madison WI
Cliff sent: More available here...
http://www.moldcast.com/products_peri_h.html
and Patric wrote:
> http://www.merlin-net.com/commerce/edit_item.asp?SKU=132960&RecNo=1
> This might fit under the category of "nighttime senior citizen
> repellent."
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Message: 12
Date: Sat, 14 Dec 2002 23:38:05 -0500
From: Steve Davis <w2sgd@juno...>
Subject: Re: Now
On Sat, 14 Dec 2002 12:15:44 -0500 Steve Davis <w2sgd@juno...> writes:
> Mark your calendar for the PBS program "NOW" with Bill Moyers,
> "The Environment in the Supreme Court". If you check <pbs.org>,
> there is stuff on global warming and sustainable environment.
Here is the interview link:
http://www.pbs.org/now/printable/transcript_hertsgaard_print.html
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