[DSLF] Digest Number 1719

[DarkSky-list@yahoogroups...]

There are 3 messages in this issue.

Topics in this digest:

      1. Re: Dark Sky Meter for research
           From: BGSTARLITE@aol...
      2. Re: LED Streetlamps
           From: "Barry Johnson" <johnsonb52@comcast...>
      3. Light Pollution in Legal Cases
           From: Mike Hansen <mhansen@einhornresearch...>


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Message: 1         
   Date: Sat, 23 Jul 2005 15:33:54 EDT
   From: BGSTARLITE@aol...
Subject: Re: Dark Sky Meter for research

In a message dated 7/22/05 8:35:14 P.M. Eastern Daylight Time,  
jhollan@amper....muni.cz writes:

And  there is another important research field: amounts of light on
overcast  nights. They should be lower than on the clear ones. However, in
urbanized  areas they are not. This is of course a major disruption of
natural  environment, with various probable impacts on wildlife. What's the
sky (or  terrain) luminance at your site on non-clear moonless nights? You
can  measure it now...
List members:
 
This is an excellent argument for metered dark sky readings. I  never thought 
of using cloud reflectance measurements to bring "to light" our  cause.
It is possible to "track down" lighting offenders by noting where the  
reflected glow is emanating from on a low cloud or mildly fog laden night. The  
color, thus, the type of light is usually more evident on foggy  nights  
Using a basic light meter may bring about acceptable results also.
It is discouraging to be able to read a newspaper in your backyard solely  by 
the light reflected off the low cloud ceiling.
Here, simple star magnitude estimates couldn't work.
 
Bill, Massachusetts  USA 
 







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



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Message: 2         
   Date: Sat, 23 Jul 2005 16:50:05 -0400
   From: "Barry Johnson" <johnsonb52@comcast...>
Subject: Re: LED Streetlamps

None of your predictions has anything to do with "cheaper."  As of today, 
LEDs have a substantial efficacy disadvantage compared to HID.
You're confusing the comparison of LEDs with low voltage incandescent lamps 
in your flashlight with the comparison of LEDs to HID for roadway lighting. 
Compared with the latter, LEDs fare badly.  Clearly, you're talking about 
pie-in-the-sky things that don't exist, with nothing to back it up.  Anyone 
can predict anything they want.

Barry Johnson

----- Original Message ----- 
From: "Eric S. Johansson" <esj@harvee...>
To: <DarkSky-list@yahoogroups...>
Sent: Friday, July 22, 2005 9:26 PM
Subject: Re: [DSLF] LED Streetlamps


> Barry Johnson wrote:
>> ----- Original Message ----- 
>> From: "Eric S. Johansson" <esj@harvee...>
>> To: <DarkSky-list@yahoogroups...>
>> Sent: Thursday, July 21, 2005 8:47 PM
>> Subject: Re: [DSLF] LED Streetlamps
>>
>>
>>
>>>like I said earlier, it potentially offers a cheaper form of better
>>>light distribution.
>>>
>>
>>
>> Then please explain how it will be cheaper when it takes 4 times as much
>> eletricity as HPS.
>
> because the cheaper refered to here is not electric power related.  what
> I said was "cheaper form of better light distribution".  the operative
> phrase being "better light distribution" as in from the luminare.  LED's
> will make high control fixtures cheaper which means it will be possible
> to control and abuse light in ways we can only begin to imagine.
>
> for example, imagine yellow illumination highlighting emergency pulloffs
> but white light on the roads.  Or street lamps with uniform
> illuminations 30 ft to either side of the pole along the road but not
> more than 1-2 ft over the road edge.  These ideas may not be practical
> today but as leds with better control are developed, what I predict will
> come closer to reality.
>
> --- eric



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Message: 3         
   Date: Sat, 23 Jul 2005 21:52:35 -0400
   From: Mike Hansen <mhansen@einhornresearch...>
Subject: Light Pollution in Legal Cases

Interesting item from a British newspaper:

http://tinyurl.com/7jk95

A reader wrote to a legal column wondering if he could sue a neighbor  
for lighting that he felt lowered the value of his property.  
Interesting response from the legal editor. May or may not be  
applicable elsewhere.

Mike Hansen
2561 Massachusetts Ave. #1
Cambridge, MA 02140-1020
(617)661-6520



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



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