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[DSLF] Digest Number 520
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There are 19 messages in this issue.
Topics in this digest:
1. Re: Glare From Vehicle Headlamps and Other Front-Mounted Lamps
From: "P. Edward Murray" <edward12@erols...>
2. Re: Lighting Levels and the Relative Cost of the Product Being Sold
From: Steve Davis <w2sgd@juno...>
3. Re: Lighting Levels Question
From: Bob Parks <bob@innovisionmm...>
4. Re: Lighting Levels Question
From: Steve Davis <w2sgd@juno...>
5. Re: Re: Lighting Levels Question
From: "David Keith" <david.keith@mindspring...>
6. RE: Re: Lighting Levels Question
From: "John Nusbaum" <jnusbaum@bellatlantic...>
7. Re: RE: 'Plasma-induction' lamps
From: "Karolyn Beebe" <keedos@earthlink...>
8. Re: Lighting Levels Question
From: "chris withheld" <chrisdlm5@hotmail...>
9. Re: Re: Lighting Levels Question
From: "David Keith" <david.keith@mindspring...>
10. Ordinance Question
From: Anthony Arrigo <Anthony.Arrigo@CampusPipeline...>
11. Re: Re: Lighting Levels Question
From: ctstarwchr@aol...
12. Re: Lighting Levels Question
From: Steve Davis <w2sgd@juno...>
13. U.S. Energy Information
From: Barry Johnson <johnsonb@ivwnet...>
14. Re: RE: 'Plasma-induction' lamps
From: "Terry McGowan" <lighting@ieee...>
15. Eye Friendly Luminaires Discovered Today
From: ctstarwchr@aol...
16. Re: New file uploaded to DarkSky-list
From: ctstarwchr@aol...
17. Re: Eye Friendly Luminaires Discovered Today
From: Paul Greenhalgh <fvas@shaw...>
18. Re: Eye Friendly Luminaires Discovered Today
From: ctstarwchr@aol...
19. RE: Eye Friendly Luminaires Discovered Today
From: "John Nusbaum" <jnusbaum@bellatlantic...>
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Message: 1
Date: Thu, 13 Dec 2001 14:10:04 -0500
From: "P. Edward Murray" <edward12@erols...>
Subject: Re: Glare From Vehicle Headlamps and Other Front-Mounted Lamps
Every time I see some car with these horrible headlights
I flash my brights at him/her.
Possibly, these folks will realize something is the matter.
Ed
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Message: 2
Date: Thu, 13 Dec 2001 14:30:53 -0500
From: Steve Davis <w2sgd@juno...>
Subject: Re: Lighting Levels and the Relative Cost of the Product Being Sold
John Nusbaum wrote:
<The lower the price the brighter the lights!>
They want volume to make up for the discount merchandise.
The moth effect! ... they can't help it... low I.Q.
Steve
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Message: 3
Date: Thu, 13 Dec 2001 14:38:36 -0500
From: Bob Parks <bob@innovisionmm...>
Subject: Re: Lighting Levels Question
Anthony,
What is your location? I am interested because .01 fc is actually a very
good level to be included in a light trespass ordinance. I would take the
time to buy a certified light meter before you try suing the county. It will
be cheaper. Here is a link to a reasonable one. Look at the bottom of the
page for the certification option.
http://www.technika.com/Sper/s840021.htm
If it turns out that the level actually exceeds the maximum permitted in the
code, I would write the head of the zoning enforcement department and cc:
your county/city elected representative. This could be a Board of Supervisor
or City Council. Most government offices have a requirement to answer a
letter in writing from a constituent. This at least forces the official to
put in writing that they can not enforce the ordinance. This also may force
the county/city to allocate more money in the future to meet its legal
responsibility. If they can not resolve the situation, I would start sending
letters to all the members of the Board of Supervisors or City Council,
making them aware of the situation. You might find one member who will make
a call for you to get the situation resolved.
Be prepared for it to take a while to resolve. Government often moves at a
glacial rate. After the situation is resolved, your could donate the meter
to the zoning department if they promise to use it to resolve other citizen
complaints. If not, donate it to our group and I will make sure it gets used
to solve similar problems.
Bob Parks
Executive Director
Virginia Outdoor Lighting Taskforce
VOLT.ORG
"If you lit your house with bare 250 watt bulbs and no shades, people would
call you crazy. But if you do it outside, they call you a DOT Lighting
Designer".
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Message: 4
Date: Thu, 13 Dec 2001 15:01:26 -0500
From: Steve Davis <w2sgd@juno...>
Subject: Re: Lighting Levels Question
Anthony Arrigo wrote:
<Would somebody know or be willing to venture a guess as to the light
level generated by a 100watt bulb about 40 feet from a property line.>
E = I / D^2 = 1800 lumens / 40 ft x 40 ft = 1.13 fc when viewed straight
on.
The horizontal component may be small, but the vertical component is
large.
The vertical component is the one that causes the trespass and glare when
viewed straight on. Vector mathematics is a little difficult to explain
without
the aid of a diagram. Good project for an IDA Info Sheet since everybody
should have the basic concepts straight.
Furthermore, measuring the horizontal footcandles is almost a useless
exercise, since the value is so low, and the meters suffer from low
sensitivity and poor cosine correction at large angles away from the
normal to the sensor.
Sorry about the techie stuff, but it is necessary. We are talking about
physics and not personal impressions. - Steve
________________________________________________________________
GET INTERNET ACCESS FROM JUNO!
Juno offers FREE or PREMIUM Internet access for less!
Join Juno today! For your FREE software, visit:
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Message: 5
Date: Thu, 13 Dec 2001 13:29:49 -0700
From: "David Keith" <david.keith@mindspring...>
Subject: Re: Re: Lighting Levels Question
I would like to (again) point out that lumens are not intensity - which is
the "I" in the Inverse Square equation E = I*cosine(incident angle) /
Dsquared. Therefore in the following example a factor of at least 4*pi
(more than 12) is missing - which does rather change the result.
As noted below, this should be done right.
Assuming that the lamp produces 1800 lumens initially - and that there is
the lumens are uniformily distributed out of the lamp - this would
correspond to an intensity estimate of 1800 lumens / 12.6 steradians or
around 143 "initial" candela - which are the SI units of intensity suitable
for use in the Inverse Square equation. For a surface "facing" the source
from 40 feet away, this would correspond to 143 cd / 40*40 feet squared or
0.09 footcandles - about 1 lux initial. In addition, any reduction in lumen
output - due to lamp age, dirt, lower voltage, etc. would further reduce the
intensity and therefore the illuminance - typically by 25% or more,
corresponding to an overall Light Loss Factor of 0.8 for "average over the
lamp life" - and down to 0.6 for incandescent lamps at end of life.
Therefore, an appropriate estimate for the *lamp-life average* illuminance
for a surface pointing toward an unshielded 100W incandescent lamp would be
around 0.8 lux.
Any other surface orientation would have illuminance values reduced by the
factor of the cosine of the angle between the path of the light and the
orientation of the surface - a number which is always less than one.
I recommend anyone interested in being able to discuss these topics
correctly read/take the IESNA Lighting Fundamentals course ED-100.
David Keith
----- Original Message -----
From: "Steve Davis" <w2sgd@juno...>
To: <DarkSky-list@yahoogroups...>
Sent: Thursday, December 13, 2001 1:01 PM
Subject: [DSLF] Re: Lighting Levels Question
>
> The horizontal component may be small, but the vertical component is
> large.
> The vertical component is the one that causes the trespass and glare when
>
> viewed straight on. Vector mathematics is a little difficult to explain
> without
> the aid of a diagram. Good project for an IDA Info Sheet since everybody
> should have the basic concepts straight.
>
> Furthermore, measuring the horizontal footcandles is almost a useless
> exercise, since the value is so low, and the meters suffer from low
> sensitivity and poor cosine correction at large angles away from the
> normal to the sensor.
>
> Sorry about the techie stuff, but it is necessary. We are talking about
> physics and not personal impressions.
>
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Message: 6
Date: Thu, 13 Dec 2001 16:21:14 -0500
From: "John Nusbaum" <jnusbaum@bellatlantic...>
Subject: RE: Re: Lighting Levels Question
>David Keith said:
>
>I would like to (again) point out that lumens are not intensity - which
is
>the "I" in the Inverse Square equation E = I*cosine(incident angle) /
>Dsquared. Therefore in the following example a factor of at least 4*pi
>(more than 12) is missing - which does rather change the result.
This is exactly why putting property line footcandle measurements in a
lighting code without also including shielding standards is so
problematic. These measurements alone have very little bearing on
glare.
I had a buddy that wanted to complain to the local DPZ about direct
glare coming off of some HPS lights from his community pool. The lights
were pretty much aimed right at his home. He did some research and
found that the county had "glare standards" that specified that action
could be taken if light falling on his property exceeded .5 footcandles.
That seemed like a pretty small number to him so he wanted to know if I
thought the lights would be in excess of this limit.
Well, we were in a school parking lot so I pulled out my light meter and
we walked towards a metal halide floodlight aimed at 90 degrees. The
glare was horrendous, but we had to get within around 50 feet before it
registered .5 footcandles with the meter pointed straight at the light!
So much for the county "glare standards"!
Needless to say my buddy was out of luck from the zoning point of view
and so are most people who are governed by this type of regulation.
Fortunately he did the common sense thing and actually spoke with his
home-owners association and they re-aimed the pool lights so that the
worst of the problem was eliminated.
John Nusbaum
Herndon VA
www.volt.org
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Message: 7
Date: Thu, 13 Dec 2001 15:04:19 -0600
From: "Karolyn Beebe" <keedos@earthlink...>
Subject: Re: RE: 'Plasma-induction' lamps
dorn@blackstarfarm...> wrote:
> I think supercritical steam plants may actually be a good bit more efficient
> than 33%. I wouldn't swear to it, but I think it may be so.
Looks like you might be right. From a 10/16/01 DOE article about
ultra-supercritical production: "Today's power plants are typically 35
percent efficient. By developing better materials that can withstand higher
temperatures, the Energy Department hopes to boost efficiencies to 52 to
55 percent. These efficiency gains, alone, would cut the release of carbon
dioxide and other emissions by nearly 30 percent."
Full text of "DOE Launches Project to Improve Materials for Supercritical
Coal Plants" is in:
http://www.fe.doe.gov/techline/tl_ultrasupercritical.shtml
That's in a Google search for "supercritical steam electricity generation".
Looking over the results I first learn more about the mess being made
world wide by cycling resources to electricity. That's what I see in light
pollution. Stars indicate health!
Ultra-supercritical power plants might slow the trashing of wilderness
in Montana, Virginia, many places, but they won't stop it. They run all
night like coal generators do, and sky glow means off-peak profits to
utility executives.
Wonder how many admire domes of glow from houses in dark enclaves. -kb
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Message: 8
Date: Thu, 13 Dec 2001 16:35:10 -0500
From: "chris withheld" <chrisdlm5@hotmail...>
Subject: Re: Lighting Levels Question
Funny you should ask...I am at this moment on the phone with clients I
represent in a lawsuit against a county relating to what we consider
irresponsible development....
Good luck with it. Chris
[ Please trim past messages before sending replies! ]
>From: Anthony Arrigo <Anthony.Arrigo@CampusPipeline...>
>Date: Thu, 13 Dec 2001 09:56:29 -0700
>
>They have a pretty decent ordiance... they've just... forgotten to enforce
>the lighting portions. Oops! I've been trying to get them to do their
> job, but... things don't happen too fast around here.
>Environmental lawyer??? Hmmmm....
>Ever sue a county :)
>
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Message: 9
Date: Thu, 13 Dec 2001 15:42:21 -0700
From: "David Keith" <david.keith@mindspring...>
Subject: Re: Re: Lighting Levels Question
I couldn't agree more - this is why the use of the technical terms is so
important.
Since glare is technically defined as "excessive contrast", the issue with
glare is not something which can be measured in lumens (or footcandles or
lux) but must be considered in terms of differences in luminance - or
ideally as ***intensity*** (that is, "source luminance" compared to a black
background) since intensity does not change over distance from the source.
Boulder County, Colorado's Land Use calls for (among other conditions):
1. Lights shall be fully shielded or arranged in a manner so that
concentrated rays of light will not shine directly onto other properties;
While I hope to settle with my neighbor about the new 250W(?) HPS wall pack
about 200 ft from my front door in a "friendly" fashion, I do think this
vague language will provide some recourse if needed. Meanwhile I am
volunteering to help with a revision which will hopefully include
illuminance restrictions - to limit spill light - and intensity and/or
shielding requirements - to limit glare.
Needless to say, it is important to understand the metrics and use the
appropriate values if the limitations are to be any use - and *then* insist
on enforcement.
David Keith
[ Please trim past messages before sending replies! ]
----- Original Message -----
From: "John Nusbaum" <jnusbaum@bellatlantic...>
Sent: Thursday, December 13, 2001 2:21 PM
>
> This is exactly why putting property line footcandle measurements in a
> lighting code without also including shielding standards is so
> problematic. These measurements alone have very little bearing on
> glare.
>
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Message: 10
Date: Thu, 13 Dec 2001 15:00:40 -0700
From: Anthony Arrigo <Anthony.Arrigo@CampusPipeline...>
Subject: Ordinance Question
Hi
The following came directly from the Summit County Ordinance:
(http://www.co.summit.ut.us/dept/planng/sville/Chptr4.htm#4.22)
F. Specific Requirements for Lighting Applications and Fixtures
1. Area Lighting. The following shall apply to area lighting
applications such as but not limited to parking lots.
...
b. Pole Top Area Symmetrical Lighting
...
iii. These fixtures shall be used in interior parking/site installations
only, and a full cut-off variety shall be used. There shall be no more
than ten (10) percent of the total lumen output of the
fixture will come out at 90 degrees above the horizontal plane of the
fixture from nadir.
I know this doesn't meet my understanding of FCO, but... that's what
I've got to work with.
Question: Our brand new COUNTY library has parking lot lights that
almost look like a glass acorn with a flat top.
What percent of total lumen output would this produce at 90*???
Hope I described the scene well enough???
To give an extra example... these shine without any obstruction down and
out.
So... they'd easily illuminate 180* and probably closer to 270*.
Thanks!
APA
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Message: 11
Date: Thu, 13 Dec 2001 18:27:08 EST
From: ctstarwchr@aol...
Subject: Re: Re: Lighting Levels Question
In a message dated 12/13/01 4:26:34 PM Eastern Standard Time,
jnusbaum@bellatlantic... writes:
> The lights were pretty much aimed right at his home. He did some
> found that the county had "glare standards" that specified
> could be taken if light falling on his property exceeded .5
> footcandles.
>
OH MY!!! 0.5 footcandles is 50 times the ground illuminance of a full
moon!!! That is nowhere near an acceptable amount of someone else's light to
bear!
Clear skies and good seeing,
Keep looking up!
Cliff Haas
Chair Light Pollution Education
Astronomical Society of Greater Hartford
http://members.aol.com/copernicanview
Light Pollution Awareness Website (LiPAW)
http://members.aol.com/ctstarwchr
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]
________________________________________________________________________
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Message: 12
Date: Thu, 13 Dec 2001 23:35:05 -0500
From: Steve Davis <w2sgd@juno...>
Subject: Re: Lighting Levels Question
Time for another engineering clarification; in other words, I screwed up!
Anthony Arrigo wrote:
<Would somebody know or be willing to venture a guess as to the light
level generated by a 100watt bulb about 40 feet from a property line.>
A 100 watt incandescent bulb produces a total of 1800 lumens.
That total is spread out in all directions. This has to be converted to
flux per unit solid angle. Since there are 4 Pi steradians in a sphere,
divide 1800 by 4 Pi to get the luminous intensity in the direction of
the target (light meter) which is 143.24 lumens.
There are lumens, and there are lumens (per steradian) which gets
confusing.
Manufacturers will put the bigger number on the package to sell product
just like horsepower for cars and watts for stereos. Which one?
Now:
E = I / * D^2 = 143.24 lumens / 40 ft * 40 ft = 0.09 fc when viewed
straight on.
The horizontal component may be small, but the vertical component is
large.
The vertical component is the one that causes the trespass and glare when
viewed straight on. Vector mathematics is a little difficult to explain
without
the aid of a diagram. Good project for an IDA Info Sheet since everybody
should have the basic concepts straight (including me).
Furthermore, measuring the horizontal footcandles is almost a useless
exercise in this case, since the value is so low, and the meters suffer
from low sensitivity and poor cosine correction at large angles away
from the normal to the sensor.
Sorry about the techie stuff, but it is necessary. We are talking about
physics and not personal impressions. - Steve
PS: Did I beat David to the punch, or should I say avoid it? :)
________________________________________________________________
GET INTERNET ACCESS FROM JUNO!
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Join Juno today! For your FREE software, visit:
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________________________________________________________________________
Message: 13
Date: Fri, 14 Dec 2001 00:19:42 -0500
From: Barry Johnson <johnsonb@ivwnet...>
Subject: U.S. Energy Information
The Statistical Abstract of the United States
(Stat Abstract) includes Section 19 Energy.
Section 19 includes national statistics by year
and by fuel on electric energy production and
consumption, and on the electric and gas utility
industries.
Section 19 Energy is available on line at
http://www.census.gov/prod/2001pubs/statab/sec19.pdf
(221K)
The principal sources of information are the
U.S.Department of Energy’s Energy Information
Administration (EIA), the Edison Electric
Institute, Washington,DC, and the American Gas
Association, Arlington,VA.
The data given seems to confirm the IDA's values
given for kilowatt hours of electricity
generated per ton of coal (about 2000 KWH/ton).
Ton here means short ton or English ton.
Regards,
Barry Johnson
[Non-text portions of this message have been removed]
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Message: 14
Date: Fri, 14 Dec 2001 00:23:14 -0500
From: "Terry McGowan" <lighting@ieee...>
Subject: Re: RE: 'Plasma-induction' lamps
Some additional corrections are needed:
The efficiency of an HPS lamp is about 35% (conversion of electrical power
to visible light).
The coefficient of utilization is the amount of light reaching the desired
area divided by the lumens of the lamp, not the luminaire.
There are three types of so-called "plasma induction" or electrodeless
fluorescent lamp/systems currently on the market in North America. Two
systems are designed for very long life applications (rated lamp lives of
100,000 hours) and have efficacies of 50-60 lumens/watt (mean values over
life). The third system (the GE Genura) is a small 23 watt integral lamp,
rated at 15,000 hours life and intended to replace a 75 watt incandescent
reflector lamp. Its efficacy is 38 lumens/watt (mean over life).
Terry McGowan
----- Original Message -----
From: Steve Davis <w2sgd@juno...>
Sent: Wednesday, December 12, 2001 10:09 PM
> Cliff wrote:
>
> <Efficacy of plasma induction lights is
> only around 70 lumens per watt and they have been available for several
> years. That taps in on the brightness scale about half way between
> mercury vapor and metal halide.>
>
> Whoa! Go to http://www.timesunion.com/communities/darksky/
> and click on "LP Basics" then "Examples".
>
> After that click on "Light Efficiency" to see what you get for your
> hard earned dollar. - Steve
>
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Message: 15
Date: Fri, 14 Dec 2001 00:25:56 EST
From: ctstarwchr@aol...
Subject: Eye Friendly Luminaires Discovered Today
Greetings:
Some good stuff came to the office today. I received two inserts for my
Architectural Area Lighting catalog that includes two very good FCO fixtures.
The Indirect is an attractive contemporary looking post top fixture that has
already been proposed for the Memphis downtown spruce up. It is awesome!
The other fixture is called the Flex. It is a very modern looking thin
profile luminaire with an intriguing mounting apparatus. The catalog for the
Flex states the following on its first page:
"The Flex is designed as a full cutoff fixture which means there is no light
emitted above 90 degrees horizontal. This insures no light is beamed into
the sky which contributes to light pollution and wastes energy." (reproduced
with permission)
See these new fixtures at:
http://www.aal.net/contemporary.htm
After reading the pamphlets, I got so excited that I called the factory to
request the photometric data files because they are not available at the
website (yet). The rep (Alison) informed me that AAL will be sending out an
informative email to over 4,000 people on their corporate mailing list
informing them about the problems of Light Pollution and good light fixtures
that can prevent it! WOW!!! I LIKE this company!!!
The rep at AAL was delighted to learn their products already appear in the
Manufacturer's section of my LiteLynx List and on the IDA website, too.
Sounds like a symbiotic relationship may be developing. We need more
luminaire manufacturers like this one who are willing to take proactive steps
to sway the current market trends!
Take a look at their products and then consider writing a short note to AAL
to thank them for developing these exciting new eye friendly outdoor lighting
products.
Architectural Area Lighting
14249 Artesia Boulevard
La Mirada, CA 90638
714-994-2700
Email: info@aal...
Website: http://www.aal.net
Clear skies and good seeing,
Keep looking up!
Cliff Haas
Chair Light Pollution Education
Astronomical Society of Greater Hartford
http://members.aol.com/copernicanview
Light Pollution Awareness Website (LiPAW)
http://members.aol.com/ctstarwchr
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: 16
Date: Fri, 14 Dec 2001 01:10:01 EST
From: ctstarwchr@aol...
Subject: Re: New file uploaded to DarkSky-list
Hello DarkSky List Forum Members,
Just want to let you know that I've uploaded one of my PowerPoint
Presentations titled, "Light Right For Sight At Night"
After signing into the Forum you can access the file at the following URL:
<http://groups.yahoo.com/group/DarkSky-list/files/Presentation/PowerPoint/LightRightForSightAtNight.ppt>
Cheers,
Cliff Haas
[Non-text portions of this message have been removed]
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Message: 17
Date: Thu, 13 Dec 2001 22:39:35 -0800
From: Paul Greenhalgh <fvas@shaw...>
Subject: Re: Eye Friendly Luminaires Discovered Today
You know Cliff, my wife made a very interesting comment tonight on our way
over to our Clubs Christmas Party tonight. We drove through that test
section the city has in place with the FCO's. I've been so busy looking up
at the lights and side areas and what not, I missed a very interesting tid
bit of information here. But thanks to the misses, it's excellent ammo if
someone asks questions about FCO's.
It is raining super hard here tonight, and as we drove through this section
the wife pops up and says, I really like these new lights, you can actually
see the lines on the road. As we left that area and into a conventional
streetlight area, the roadway lines disappeared in the glare of headlights
and streetlights. HOLY Cow she is so right, how could have I missed this?!
Another check mark for the information booklet I thought!
It just goes to show you behind ever good man is an awesome woman!
Clear Skies!
_________________________________________
Paul Greenhalgh (Director)
Fraser Valley Astronomers Society
British Columbia Canada
http://www.fvas.net
________________________________
________________________________________________________________________
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Message: 18
Date: Fri, 14 Dec 2001 03:02:42 EST
From: ctstarwchr@aol...
Subject: Re: Eye Friendly Luminaires Discovered Today
Hi Paul:
Thanks for the report. Sounds like you have a real keeper there! ;-) Bet
she is pretty proud of you too! She should be, because if it wasn't for your
efforts those FCOs wouldn't be there! Keep up the great work!
Tonight the weather was very misty on the ride home from work. Connecticut
DOT has installed hundreds of FCOs along Route 91 in the New Haven area where
I get on the highway to return home. What a treat it is now to drive on this
road under inclement conditions! The light cones shining down onto the
roadway were completely visible from each luminaire. Although these
luminaires are tilted upward by 6 degrees for greater forward throw, the
uplighting effect was nonexistent. The sky overhead is completely dark and
the road is illuminated as well if not better than it is under the same
spacing used for semi-cutoff luminaires.
About 4 miles to the north, offensive glare blasts straight into drivers'
eyes for several miles and it is coming from the lack luster standard fare of
semi-cutoff cobraheads overhead. I've been noticing people slamming on their
brakes as soon as they get blasted by these lights when coming from the much
better quality lighting offered by FCOs.
What is most interesting is the fact that each semi-cutoff luminaire appears
ringed by a 360 degree halo, indicating that just as much light is going in
all directions from these highly efficient energy wasters! Having reviewed
hundreds of photometric files I know this is not what the manufacturers data
suggests, but this ubiquitous condition happens just the same. It is a
fairly sure indication from my observations that most skyglow occurs because
of semi-cutoff roadway lighting directly shining into the sky and NOT because
of upward reflected luminance/exitance coming from the roadway.
No matter what angle these semi-cutoff luminaires are viewed from, that halo
veil of luminance still encircles each one of them completely! A cutoff line
should be visible at some point because of the opaque housing, but it doesn't
seem apparent once that light passes through the refracting lens. It may be
there and is just getting overwritten on the retina by the direct glare
coming from these horrible lights. The science of photometry presently does
not consider the effect a luminaire has on aerosols. It should because this
indicator will enhance the development of more efficient reflector designs.
No light cone shining down onto the roadway where illumination is desired was
visible at all throughout the entire expanse that was illuminated with
semi-cutoff cobras. Light was indeed ubiquitous, but it was not shining
where it was needed. Although it was not measured with a meter, the visual
perception of lighting uniformity (ground illuminance) was absolutely no
different than it was with the FCOs either. Some engineers claim uniformity
to be a problem when using FCO, but it surely doesn't seem apparent in
applied practice on the roads. What was much different is the fact that FCO
lighting made it so much easier to see the road and no eerie luminescent glow
appeared in the air except within the light cones themselves.
It never ceases to amaze me that some lighting engineers will strongly insist
that semi-cutoff lighting is so much better and so much more efficient than
FCO. That may be the result of data extrapolation crunched in a spreadsheet,
but it certainly is not the case when driving on the roadway. It is a
pleasure to be able to drive at night without having to pull down the sun
visor to ward off the glare!
One more new FCO was noticed installed on this road today! It was in the
middle of a string of semi-cutoffs. Connecticut has gone from having only 8
FCOs on state roads in December of 1999, to having literally hundreds today
and it is getting better each month as time progresses onward. I also
noticed 25 more new FCO cobras on city roads while out shopping in Middletown
tonight. :-)
>From the document titled "Highway Lighting and Driver Performance" the first
line says it all.
http://ntl.bts.gov/DOCS/97095/ch02/body_ch02_04.html
It also says, "...there have been some reports of accident rates increasing
after installation of fixed lighting systems (Gordon and Schwab, 1979)."
Light right for sight at night. Light the road and not the drivers'
eyeballs! Turn semi-cutoff lighting into paper weights and door stops. At
least then they will serve some form of useful purpose for society.
Clear skies and good seeing,
Keep looking up!
Cliff Haas
Chair Light Pollution Education
Astronomical Society of Greater Hartford
http://members.aol.com/copernicanview
Light Pollution Awareness Website (LiPAW)
http://members.aol.com/ctstarwchr
Fight for your right to see stars in the night!
Join IDA Today! http://www.darksky.org
In a message dated 12/14/01 1:52:36 AM Eastern Standard Time, fvas@shaw...
writes:
> It is raining super hard here tonight, and as we drove through this section
> the wife pops up and says, I really like these new lights, you can actually
> see the lines on the road. As we left that area and into a conventional
> streetlight area, the roadway lines disappeared in the glare of headlights
> and streetlights. HOLY Cow she is so right, how could have I missed this?!
> Another check mark for the information booklet I thought!
>
> It just goes to show you behind ever good man is an awesome woman!
>
[Non-text portions of this message have been removed]
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Message: 19
Date: Fri, 14 Dec 2001 09:22:05 -0500
From: "John Nusbaum" <jnusbaum@bellatlantic...>
Subject: RE: Eye Friendly Luminaires Discovered Today
>Cliff said:
>
>The Indirect is an attractive contemporary looking post top fixture
that >has already been proposed for the Memphis downtown spruce up. It
is >awesome!
Speaking of indirect outdoor lighting ... Has anyone out there seen a
WaWa Convenience store? They use indirect lighting on the station
canopies! It is really quite nice!
You can click on this link to see what the station looks like.
http://www.wawa.com/wawaprofile/pro-home.asp
The lights are mounted on each of the pillars and shine up into the
canopy. The light reflects down and they give very even illumination.
Because the canopy is angled slightly in towards the store, the light is
also reflected onto the walkway and towards the front of the building.
It was pretty creative and there was no glare for sure.
I first saw these stores on my way to Ocean City Maryland last spring
for a couple of days of feasting on Crab Cakes! I'm kicking myself
right now for not pulling out my camera and getting a few pics.
-John Nusbaum
www.volt.org
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