Greenie KOOKS rarely address one easy-to-fix energy waste problem:Light pollution

They don't even need hyper-expensive LEDs being pushed by the lighting
industry, they just need to get rid of the ancient, 1950's-style
street light fixtures and replace them with shielded ones.

Light pollution:

25 April 2013 Last updated at 13:14 ET
LED streetlamp aims to improve public's view of stars
By Leo Kelion Technology reporter

Researchers believe they have come up with a new type of LED-powered
streetlamp that could radically reduce light pollution.

Current designs "leak" large amounts of light in unwanted directions,
obscuring views of the stars, wasting energy and making it harder for
drivers to see.

The team, based in Mexico and Japan, said they believed their solution
was the "best ever reported".

However, they have yet to turn their theory into a working prototype.

The study - carried out by scientists in Mexico and Taiwan - appears
in the open-access journal Optics Express.
LED lens

According to the researchers, conventional street lamps - which use
high-pressure sodium or mercury vapour - scatter up to 20% of their
energy horizontally or vertically because it is difficult to control
their beams.

It is easier to direct light from LEDs because it is being emitted
from a smaller area.

So, while manufacturers controlled the direction of the light rays
from older lamps using a reflector typically made out of polished
aluminium, they can now take advantage of lenses to be more precise.

The researchers say the best LED (light-emitting diode) streetlamps on
the market direct about 10% of their energy horizontally or
vertically.

But they claim their own invention could further reduce the amount to
just 2%.

Their proposed lamp uses three features to ensure the vast majority of
its light is limited to a pre-determined rectangular shape covering
the road:

A special "total internal reflection" lens for each LED designed
to focus its light's rays so that they travel parallel to each other
in a single direction. This is rather than criss-crossing and
diverging from each other causing many to spill beyond the target
area.
A reflecting cavity into which the lens-covered LEDs are fitted.
This helps "recycle" any light rays which fail to travel the desired
path.
A diffuser through which the focused light passes to help tackle
unwanted glare.

The researchers suggest that the set-up would also save on electricity
costs since it should require between 10 and 50% less power to
illuminate a section of road than current LED streetlamps.

They added that they were now working to build a prototype and hoped
to have it completed by October.
LED revolution

London-based light design firm Speirs and Major unveiled an LED-based
streetlamp design of its own last year.

The firm's associate director, Andrew Howis, said the latest study was
just one of several efforts under way aimed at tackling the problem of
stray light.

"As a result of LEDs it is now possible to place light exactly where
it is needed and to greatly reduce spill light and energy wastage," he
said.

"This new research is an example of the innovation in LED optics - of
which there are many - which uses a fairly sophisticated optical
system to produce an optimised distribution for street lighting.

"It sounds like an advance on what is already available, but of itself
is not revolutionary. The change from conventional light sources to
LED is the revolution."

The Campaign to Protect Rural England (CPRE) also gave the new work a
qualified welcome.

The lobby group carries out an annual star count to publicise the
problem of light pollution which it says disrupts wildlife and
people's sleep.

It noted that the new technology would only be of use if councils were
willing to invest in it.

"From 1993 to 2000, light pollution in England increased by 26%, which
shows the huge amount of energy and money wasted," said campaigner
Emma Marrington.

"It should be seen as an investment for local authorities to install
more efficient street lighting, which will save money and energy waste
in the long-term.

"Design is great but councils have to follow through with investment."

"$27 TRILLION to pay for Kyoto" wrote:
They don't even need hyper-expensive LEDs being pushed by the lighting
industry, they just need to get rid of the ancient, 1950's-style
street light fixtures and replace them with shielded ones.

Light pollution:

25 April 2013 Last updated at 13:14 ET
LED streetlamp aims to improve public's view of stars
By Leo Kelion Technology reporter

Researchers believe they have come up with a new type of LED-powered
streetlamp that could radically reduce light pollution.

Current designs "leak" large amounts of light in unwanted directions,
obscuring views of the stars, wasting energy and making it harder for
drivers to see.

The team, based in Mexico and Japan, said they believed their solution
was the "best ever reported".

However, they have yet to turn their theory into a working prototype.

The study - carried out by scientists in Mexico and Taiwan - appears
in the open-access journal Optics Express.
LED lens

According to the researchers, conventional street lamps - which use
high-pressure sodium or mercury vapour - scatter up to 20% of their
energy horizontally or vertically because it is difficult to control
their beams.

It is easier to direct light from LEDs because it is being emitted
from a smaller area.

So, while manufacturers controlled the direction of the light rays
from older lamps using a reflector typically made out of polished
aluminium, they can now take advantage of lenses to be more precise.

The researchers say the best LED (light-emitting diode) streetlamps on
the market direct about 10% of their energy horizontally or
vertically.

But they claim their own invention could further reduce the amount to
just 2%.

Their proposed lamp uses three features to ensure the vast majority of
its light is limited to a pre-determined rectangular shape covering
the road:

A special "total internal reflection" lens for each LED designed
to focus its light's rays so that they travel parallel to each other
in a single direction. This is rather than criss-crossing and
diverging from each other causing many to spill beyond the target
area.
A reflecting cavity into which the lens-covered LEDs are fitted.
This helps "recycle" any light rays which fail to travel the desired
path.
A diffuser through which the focused light passes to help tackle
unwanted glare.

The researchers suggest that the set-up would also save on electricity
costs since it should require between 10 and 50% less power to
illuminate a section of road than current LED streetlamps.

They added that they were now working to build a prototype and hoped
to have it completed by October.
LED revolution

London-based light design firm Speirs and Major unveiled an LED-based
streetlamp design of its own last year.

The firm's associate director, Andrew Howis, said the latest study was
just one of several efforts under way aimed at tackling the problem of
stray light.

"As a result of LEDs it is now possible to place light exactly where
it is needed and to greatly reduce spill light and energy wastage," he
said.

"This new research is an example of the innovation in LED optics - of
which there are many - which uses a fairly sophisticated optical
system to produce an optimised distribution for street lighting.

"It sounds like an advance on what is already available, but of itself
is not revolutionary. The change from conventional light sources to
LED is the revolution."

The Campaign to Protect Rural England (CPRE) also gave the new work a
qualified welcome.

The lobby group carries out an annual star count to publicise the
problem of light pollution which it says disrupts wildlife and
people's sleep.

It noted that the new technology would only be of use if councils were
willing to invest in it.

"From 1993 to 2000, light pollution in England increased by 26%, which
shows the huge amount of energy and money wasted," said campaigner
Emma Marrington.

"It should be seen as an investment for local authorities to install
more efficient street lighting, which will save money and energy waste
in the long-term.

"Design is great but councils have to follow through with investment."

You would have a difficult job finding any 1950s street lamps in Britain.

On Apr 25, 2:32*pm, Mike Collins wrote:
"$27 TRILLION to pay for Kyoto" wrote:









They don't even need hyper-expensive LEDs being pushed by the lighting
industry, they just need to get rid of the ancient, 1950's-style
street light fixtures and replace them with shielded ones.

Light pollution:

*25 April 2013 Last updated at 13:14 ET
LED streetlamp aims to improve public's view of stars
By Leo Kelion Technology reporter

Researchers believe they have come up with a new type of LED-powered
streetlamp that could radically reduce light pollution.

Current designs "leak" large amounts of light in unwanted directions,
obscuring views of the stars, wasting energy and making it harder for
drivers to see.

The team, based in Mexico and Japan, said they believed their solution
was the "best ever reported".

However, they have yet to turn their theory into a working prototype.

The study - carried out by scientists in Mexico and Taiwan - appears
in the open-access journal Optics Express.
LED lens

According to the researchers, conventional street lamps - which use
high-pressure sodium or mercury vapour - scatter up to 20% of their
energy horizontally or vertically because it is difficult to control
their beams.

It is easier to direct light from LEDs because it is being emitted
from a smaller area.

So, while manufacturers controlled the direction of the light rays
from older lamps using a reflector typically made out of polished
aluminium, they can now take advantage of lenses to be more precise.

The researchers say the best LED (light-emitting diode) streetlamps on
the market direct about 10% of their energy horizontally or
vertically.

But they claim their own invention could further reduce the amount to
just 2%.

Their proposed lamp uses three features to ensure the vast majority of
its light is limited to a pre-determined rectangular shape covering
the road:

* * A special "total internal reflection" lens for each LED designed
to focus its light's rays so that they travel parallel to each other
in a single direction. This is rather than criss-crossing and
diverging from each other causing many to spill beyond the target
area.
* * A reflecting cavity into which the lens-covered LEDs are fitted..
This helps "recycle" any light rays which fail to travel the desired
path.
* * A diffuser through which the focused light passes to help tackle
unwanted glare.

The researchers suggest that the set-up would also save on electricity
costs since it should require between 10 and 50% less power to
illuminate a section of road than current LED streetlamps.

They added that they were now working to build a prototype and hoped
to have it completed by October.
LED revolution

London-based light design firm Speirs and Major unveiled an LED-based
streetlamp design of its own last year.

The firm's associate director, Andrew Howis, said the latest study was
just one of several efforts under way aimed at tackling the problem of
stray light.

"As a result of LEDs it is now possible to place light exactly where
it is needed and to greatly reduce spill light and energy wastage," he
said.

"This new research is an example of the innovation in LED optics - of
which there are many - which uses a fairly sophisticated optical
system to produce an optimised distribution for street lighting.

"It sounds like an advance on what is already available, but of itself
is not revolutionary. The change from conventional light sources to
LED is the revolution."

The Campaign to Protect Rural England (CPRE) also gave the new work a
qualified welcome.

The lobby group carries out an annual star count to publicise the
problem of light pollution which it says disrupts wildlife and
people's sleep.

It noted that the new technology would only be of use if councils were
willing to invest in it.

"From 1993 to 2000, light pollution in England increased by 26%, which
shows the huge amount of energy and money wasted," said campaigner
Emma Marrington.

"It should be seen as an investment for local authorities to install
more efficient street lighting, which will save money and energy waste
in the long-term.

"Design is great but councils have to follow through with investment."

You would have a difficult job finding any 1950s street lamps in Britain.

Not in North America.

"$27 TRILLION to pay for Kyoto" wrote:
On Apr 25, 2:32 pm, Mike Collins wrote:
"$27 TRILLION to pay for Kyoto" wrote:









They don't even need hyper-expensive LEDs being pushed by the lighting
industry, they just need to get rid of the ancient, 1950's-style
street light fixtures and replace them with shielded ones.

Light pollution:

25 April 2013 Last updated at 13:14 ET
LED streetlamp aims to improve public's view of stars
By Leo Kelion Technology reporter

Researchers believe they have come up with a new type of LED-powered
streetlamp that could radically reduce light pollution.

Current designs "leak" large amounts of light in unwanted directions,
obscuring views of the stars, wasting energy and making it harder for
drivers to see.

The team, based in Mexico and Japan, said they believed their solution
was the "best ever reported".

However, they have yet to turn their theory into a working prototype.

The study - carried out by scientists in Mexico and Taiwan - appears
in the open-access journal Optics Express.
LED lens

According to the researchers, conventional street lamps - which use
high-pressure sodium or mercury vapour - scatter up to 20% of their
energy horizontally or vertically because it is difficult to control
their beams.

It is easier to direct light from LEDs because it is being emitted
from a smaller area.

So, while manufacturers controlled the direction of the light rays
from older lamps using a reflector typically made out of polished
aluminium, they can now take advantage of lenses to be more precise.

The researchers say the best LED (light-emitting diode) streetlamps on
the market direct about 10% of their energy horizontally or
vertically.

But they claim their own invention could further reduce the amount to
just 2%.

Their proposed lamp uses three features to ensure the vast majority of
its light is limited to a pre-determined rectangular shape covering
the road:

A special "total internal reflection" lens for each LED designed
to focus its light's rays so that they travel parallel to each other
in a single direction. This is rather than criss-crossing and
diverging from each other causing many to spill beyond the target
area.
A reflecting cavity into which the lens-covered LEDs are fitted.
This helps "recycle" any light rays which fail to travel the desired
path.
A diffuser through which the focused light passes to help tackle
unwanted glare.

The researchers suggest that the set-up would also save on electricity
costs since it should require between 10 and 50% less power to
illuminate a section of road than current LED streetlamps.

They added that they were now working to build a prototype and hoped
to have it completed by October.
LED revolution

London-based light design firm Speirs and Major unveiled an LED-based
streetlamp design of its own last year.

The firm's associate director, Andrew Howis, said the latest study was
just one of several efforts under way aimed at tackling the problem of
stray light.

"As a result of LEDs it is now possible to place light exactly where
it is needed and to greatly reduce spill light and energy wastage," he
said.

"This new research is an example of the innovation in LED optics - of
which there are many - which uses a fairly sophisticated optical
system to produce an optimised distribution for street lighting.

"It sounds like an advance on what is already available, but of itself
is not revolutionary. The change from conventional light sources to
LED is the revolution."

The Campaign to Protect Rural England (CPRE) also gave the new work a
qualified welcome.

The lobby group carries out an annual star count to publicise the
problem of light pollution which it says disrupts wildlife and
people's sleep.

It noted that the new technology would only be of use if councils were
willing to invest in it.

"From 1993 to 2000, light pollution in England increased by 26%, which
shows the huge amount of energy and money wasted," said campaigner
Emma Marrington.

"It should be seen as an investment for local authorities to install
more efficient street lighting, which will save money and energy waste
in the long-term.

"Design is great but councils have to follow through with investment."

You would have a difficult job finding any 1950s street lamps in Britain.

Not in North America.

You're quoting a British story.

On Apr 25, 4:27*pm, Mike Collins wrote:
"$27 TRILLION to pay for Kyoto" wrote:









On Apr 25, 2:32 pm, Mike Collins wrote:
"$27 TRILLION to pay for Kyoto" wrote:

They don't even need hyper-expensive LEDs being pushed by the lighting
industry, they just need to get rid of the ancient, 1950's-style
street light fixtures and replace them with shielded ones.

Light pollution:

*25 April 2013 Last updated at 13:14 ET
LED streetlamp aims to improve public's view of stars
By Leo Kelion Technology reporter

Researchers believe they have come up with a new type of LED-powered
streetlamp that could radically reduce light pollution.

Current designs "leak" large amounts of light in unwanted directions,
obscuring views of the stars, wasting energy and making it harder for
drivers to see.

The team, based in Mexico and Japan, said they believed their solution
was the "best ever reported".

However, they have yet to turn their theory into a working prototype.

The study - carried out by scientists in Mexico and Taiwan - appears
in the open-access journal Optics Express.
LED lens

According to the researchers, conventional street lamps - which use
high-pressure sodium or mercury vapour - scatter up to 20% of their
energy horizontally or vertically because it is difficult to control
their beams.

It is easier to direct light from LEDs because it is being emitted
from a smaller area.

So, while manufacturers controlled the direction of the light rays
from older lamps using a reflector typically made out of polished
aluminium, they can now take advantage of lenses to be more precise.

The researchers say the best LED (light-emitting diode) streetlamps on
the market direct about 10% of their energy horizontally or
vertically.

But they claim their own invention could further reduce the amount to
just 2%.

Their proposed lamp uses three features to ensure the vast majority of
its light is limited to a pre-determined rectangular shape covering
the road:

* * A special "total internal reflection" lens for each LED designed
to focus its light's rays so that they travel parallel to each other
in a single direction. This is rather than criss-crossing and
diverging from each other causing many to spill beyond the target
area.
* * A reflecting cavity into which the lens-covered LEDs are fitted.
This helps "recycle" any light rays which fail to travel the desired
path.
* * A diffuser through which the focused light passes to help tackle
unwanted glare.

The researchers suggest that the set-up would also save on electricity
costs since it should require between 10 and 50% less power to
illuminate a section of road than current LED streetlamps.

They added that they were now working to build a prototype and hoped
to have it completed by October.
LED revolution

London-based light design firm Speirs and Major unveiled an LED-based
streetlamp design of its own last year.

The firm's associate director, Andrew Howis, said the latest study was
just one of several efforts under way aimed at tackling the problem of
stray light.

"As a result of LEDs it is now possible to place light exactly where
it is needed and to greatly reduce spill light and energy wastage," he
said.

"This new research is an example of the innovation in LED optics - of
which there are many - which uses a fairly sophisticated optical
system to produce an optimised distribution for street lighting.

"It sounds like an advance on what is already available, but of itself
is not revolutionary. The change from conventional light sources to
LED is the revolution."

The Campaign to Protect Rural England (CPRE) also gave the new work a
qualified welcome.

The lobby group carries out an annual star count to publicise the
problem of light pollution which it says disrupts wildlife and
people's sleep.

It noted that the new technology would only be of use if councils were
willing to invest in it.

"From 1993 to 2000, light pollution in England increased by 26%, which
shows the huge amount of energy and money wasted," said campaigner
Emma Marrington.

"It should be seen as an investment for local authorities to install
more efficient street lighting, which will save money and energy waste
in the long-term.

"Design is great but councils have to follow through with investment."

You would have a difficult job finding any 1950s street lamps in Britain.

Not in North America.

You're quoting a British story.

Point is, they don't need hyper-expensive LED's to direct light at
pavement instead of the sky.

RichA wrote:
On Apr 25, 4:27 pm, Mike Collins wrote:
"$27 TRILLION to pay for Kyoto" wrote:









On Apr 25, 2:32 pm, Mike Collins wrote:
"$27 TRILLION to pay for Kyoto" wrote:

They don't even need hyper-expensive LEDs being pushed by the lighting
industry, they just need to get rid of the ancient, 1950's-style
street light fixtures and replace them with shielded ones.

Light pollution:

25 April 2013 Last updated at 13:14 ET
LED streetlamp aims to improve public's view of stars
By Leo Kelion Technology reporter

Researchers believe they have come up with a new type of LED-powered
streetlamp that could radically reduce light pollution.

Current designs "leak" large amounts of light in unwanted directions,
obscuring views of the stars, wasting energy and making it harder for
drivers to see.

The team, based in Mexico and Japan, said they believed their solution
was the "best ever reported".

However, they have yet to turn their theory into a working prototype.

The study - carried out by scientists in Mexico and Taiwan - appears
in the open-access journal Optics Express.
LED lens

According to the researchers, conventional street lamps - which use
high-pressure sodium or mercury vapour - scatter up to 20% of their
energy horizontally or vertically because it is difficult to control
their beams.

It is easier to direct light from LEDs because it is being emitted
from a smaller area.

So, while manufacturers controlled the direction of the light rays
from older lamps using a reflector typically made out of polished
aluminium, they can now take advantage of lenses to be more precise.

The researchers say the best LED (light-emitting diode) streetlamps on
the market direct about 10% of their energy horizontally or
vertically.

But they claim their own invention could further reduce the amount to
just 2%.

Their proposed lamp uses three features to ensure the vast majority of
its light is limited to a pre-determined rectangular shape covering
the road:

A special "total internal reflection" lens for each LED designed
to focus its light's rays so that they travel parallel to each other
in a single direction. This is rather than criss-crossing and
diverging from each other causing many to spill beyond the target
area.
A reflecting cavity into which the lens-covered LEDs are fitted.
This helps "recycle" any light rays which fail to travel the desired
path.
A diffuser through which the focused light passes to help tackle
unwanted glare.

The researchers suggest that the set-up would also save on electricity
costs since it should require between 10 and 50% less power to
illuminate a section of road than current LED streetlamps.

They added that they were now working to build a prototype and hoped
to have it completed by October.
LED revolution

London-based light design firm Speirs and Major unveiled an LED-based
streetlamp design of its own last year.

The firm's associate director, Andrew Howis, said the latest study was
just one of several efforts under way aimed at tackling the problem of
stray light.

"As a result of LEDs it is now possible to place light exactly where
it is needed and to greatly reduce spill light and energy wastage," he
said.

"This new research is an example of the innovation in LED optics - of
which there are many - which uses a fairly sophisticated optical
system to produce an optimised distribution for street lighting.

"It sounds like an advance on what is already available, but of itself
is not revolutionary. The change from conventional light sources to
LED is the revolution."

The Campaign to Protect Rural England (CPRE) also gave the new work a
qualified welcome.

The lobby group carries out an annual star count to publicise the
problem of light pollution which it says disrupts wildlife and
people's sleep.

It noted that the new technology would only be of use if councils were
willing to invest in it.

"From 1993 to 2000, light pollution in England increased by 26%, which
shows the huge amount of energy and money wasted," said campaigner
Emma Marrington.

"It should be seen as an investment for local authorities to install
more efficient street lighting, which will save money and energy waste
in the long-term.

"Design is great but councils have to follow through with investment."

You would have a difficult job finding any 1950s street lamps in Britain.

Not in North America.

You're quoting a British story.

Point is, they don't need hyper-expensive LED's to direct light at
pavement instead of the sky.

Of course.
But if you are replacing the lamps anyway LEDs could be a good choice .
Depends in the power consumption and overall cost over the lifetime of the
lamp.

On 25/04/2013 21:27, Mike Collins wrote:
"$27 TRILLION to pay for Kyoto" wrote:
On Apr 25, 2:32 pm, Mike Collins wrote:
"$27 TRILLION to pay for Kyoto" wrote:

They don't even need hyper-expensive LEDs being pushed by the lighting
industry, they just need to get rid of the ancient, 1950's-style
street light fixtures and replace them with shielded ones.

Light pollution:

25 April 2013 Last updated at 13:14 ET
LED streetlamp aims to improve public's view of stars
By Leo Kelion Technology reporter

Researchers believe they have come up with a new type of LED-powered
streetlamp that could radically reduce light pollution.

Current designs "leak" large amounts of light in unwanted directions,
obscuring views of the stars, wasting energy and making it harder for
drivers to see.

This is incorrect to begin with. All of the new full cut-off typically
cobra head designs leak zero light above the horizontal. Actually not
quite prefectly since they insist on painting the poles light grey.

The team, based in Mexico and Japan, said they believed their solution
was the "best ever reported".

However, they have yet to turn their theory into a working prototype.

The study - carried out by scientists in Mexico and Taiwan - appears
in the open-access journal Optics Express.
LED lens

According to the researchers, conventional street lamps - which use
high-pressure sodium or mercury vapour - scatter up to 20% of their
energy horizontally or vertically because it is difficult to control
their beams.

It is easier to direct light from LEDs because it is being emitted
from a smaller area.

The new LED designs (I have seen them at a UK jamboree to con councils
into spending insanely large amounts of money for illusory future
"savings") are a control freaks paradise. Every LED has an independent
optical train consisting of a deep parabola and a fancy cast acrylic
lens on the front. They have an irregular outer surface to make them
harder to clean and so are not quite full cutoff once they get dirty.

So, while manufacturers controlled the direction of the light rays
from older lamps using a reflector typically made out of polished
aluminium, they can now take advantage of lenses to be more precise.

The researchers say the best LED (light-emitting diode) streetlamps on
the market direct about 10% of their energy horizontally or
vertically.

Perhaps they mean upwards? This is nonsense anyway. There are already
trivial designs that emit no light above the horizontal (at least if the
monkeys that install then level the units after fitting).

But they claim their own invention could further reduce the amount to
just 2%.

Which is pointless since all of the light that hits the ground with an
average albedo of about 20-30% will go back up again roughly 10ns later.

Their proposed lamp uses three features to ensure the vast majority of
its light is limited to a pre-determined rectangular shape covering
the road:

A special "total internal reflection" lens for each LED designed
to focus its light's rays so that they travel parallel to each other
in a single direction. This is rather than criss-crossing and
diverging from each other causing many to spill beyond the target
area.
A reflecting cavity into which the lens-covered LEDs are fitted.
This helps "recycle" any light rays which fail to travel the desired
path.
A diffuser through which the focused light passes to help tackle
unwanted glare.

They give an interesting strobe effect when driving past because of the
extreme directivity - at least the ones I have seen do.

The researchers suggest that the set-up would also save on electricity
costs since it should require between 10 and 50% less power to
illuminate a section of road than current LED streetlamps.

They added that they were now working to build a prototype and hoped
to have it completed by October.
LED revolution

London-based light design firm Speirs and Major unveiled an LED-based
streetlamp design of its own last year.

Interesting. Most of the ones I have seen in the UK have been designed
for a much lower latitude and have excessive sized aluminium heatsinks
to handle nighttime ambient temperatures that are *NEVER* seen in the UK.

The firm's associate director, Andrew Howis, said the latest study was
just one of several efforts under way aimed at tackling the problem of
stray light.

"As a result of LEDs it is now possible to place light exactly where
it is needed and to greatly reduce spill light and energy wastage," he
said.

"This new research is an example of the innovation in LED optics - of
which there are many - which uses a fairly sophisticated optical
system to produce an optimised distribution for street lighting.

"It sounds like an advance on what is already available, but of itself
is not revolutionary. The change from conventional light sources to
LED is the revolution."

The Campaign to Protect Rural England (CPRE) also gave the new work a
qualified welcome.

I'll bet they haven't looked too carefully at them then. I am sure it is
a great scheme for the installers, but the early adopters will get their
fingers severely burned with a technology that isn't yet ready. The MTBF
of these things has not matched the claims made for them.

The lobby group carries out an annual star count to publicise the
problem of light pollution which it says disrupts wildlife and
people's sleep.

It noted that the new technology would only be of use if councils were
willing to invest in it.

"From 1993 to 2000, light pollution in England increased by 26%, which
shows the huge amount of energy and money wasted," said campaigner
Emma Marrington.

"It should be seen as an investment for local authorities to install
more efficient street lighting, which will save money and energy waste
in the long-term.

"Design is great but councils have to follow through with investment."

You would have a difficult job finding any 1950s street lamps in Britain.

Not in North America.

You're quoting a British story.



--
Regards,
Martin Brown

On Monday, April 29, 2013 at 06:37 UTC, Martin Brown wrote:

But they claim their own invention could further reduce the amount to
just 2%.

Which is pointless since all of the light that hits the ground with an
average albedo of about 20-30% will go back up again roughly 10ns later.

Exactly! At least we could filter LPS, now we have a mixture of LED, HPS, and LPS.
So we go from mag 2 skies to mag 3 - BFD! Anything less than mag 5 is fookin' useless...

The Campaign to Protect Rural England (CPRE) also gave the new work a
qualified welcome.

I'll bet they haven't looked too carefully at them then. I am sure it is
a great scheme for the installers, but the early adopters will get their
fingers severely burned with a technology that isn't yet ready. The MTBF
of these things has not matched the claims made for them.

Ah well, they only have to last a political term... ;-)

On Apr 28, 5:27*am, Mike Collins wrote:
RichA wrote:
On Apr 25, 4:27 pm, Mike Collins wrote:
"$27 TRILLION to pay for Kyoto" wrote:

On Apr 25, 2:32 pm, Mike Collins wrote:
"$27 TRILLION to pay for Kyoto" wrote:

They don't even need hyper-expensive LEDs being pushed by the lighting
industry, they just need to get rid of the ancient, 1950's-style
street light fixtures and replace them with shielded ones.

Light pollution:

*25 April 2013 Last updated at 13:14 ET
LED streetlamp aims to improve public's view of stars
By Leo Kelion Technology reporter

Researchers believe they have come up with a new type of LED-powered
streetlamp that could radically reduce light pollution.

Current designs "leak" large amounts of light in unwanted directions,
obscuring views of the stars, wasting energy and making it harder for
drivers to see.

The team, based in Mexico and Japan, said they believed their solution
was the "best ever reported".

However, they have yet to turn their theory into a working prototype.

The study - carried out by scientists in Mexico and Taiwan - appears
in the open-access journal Optics Express.
LED lens

According to the researchers, conventional street lamps - which use
high-pressure sodium or mercury vapour - scatter up to 20% of their
energy horizontally or vertically because it is difficult to control
their beams.

It is easier to direct light from LEDs because it is being emitted
from a smaller area.

So, while manufacturers controlled the direction of the light rays
from older lamps using a reflector typically made out of polished
aluminium, they can now take advantage of lenses to be more precise..

The researchers say the best LED (light-emitting diode) streetlamps on
the market direct about 10% of their energy horizontally or
vertically.

But they claim their own invention could further reduce the amount to
just 2%.

Their proposed lamp uses three features to ensure the vast majority of
its light is limited to a pre-determined rectangular shape covering
the road:

* * A special "total internal reflection" lens for each LED designed
to focus its light's rays so that they travel parallel to each other
in a single direction. This is rather than criss-crossing and
diverging from each other causing many to spill beyond the target
area.
* * A reflecting cavity into which the lens-covered LEDs are fitted.
This helps "recycle" any light rays which fail to travel the desired
path.
* * A diffuser through which the focused light passes to help tackle
unwanted glare.

The researchers suggest that the set-up would also save on electricity
costs since it should require between 10 and 50% less power to
illuminate a section of road than current LED streetlamps.

They added that they were now working to build a prototype and hoped
to have it completed by October.
LED revolution

London-based light design firm Speirs and Major unveiled an LED-based
streetlamp design of its own last year.

The firm's associate director, Andrew Howis, said the latest study was
just one of several efforts under way aimed at tackling the problem of
stray light.

"As a result of LEDs it is now possible to place light exactly where
it is needed and to greatly reduce spill light and energy wastage," he
said.

"This new research is an example of the innovation in LED optics - of
which there are many - which uses a fairly sophisticated optical
system to produce an optimised distribution for street lighting.

"It sounds like an advance on what is already available, but of itself
is not revolutionary. The change from conventional light sources to
LED is the revolution."

The Campaign to Protect Rural England (CPRE) also gave the new work a
qualified welcome.

The lobby group carries out an annual star count to publicise the
problem of light pollution which it says disrupts wildlife and
people's sleep.

It noted that the new technology would only be of use if councils were
willing to invest in it.

"From 1993 to 2000, light pollution in England increased by 26%, which
shows the huge amount of energy and money wasted," said campaigner
Emma Marrington.

"It should be seen as an investment for local authorities to install
more efficient street lighting, which will save money and energy waste
in the long-term.

"Design is great but councils have to follow through with investment."

You would have a difficult job finding any 1950s street lamps in Britain.

Not in North America.

You're quoting a British story.

Point is, they don't need hyper-expensive LED's to direct light at
pavement instead of the sky.

Of course.
But if you are replacing the lamps anyway LEDs could be a good choice .
Depends in the power consumption and overall cost over the lifetime of the
lamp.

Meanwhile, the so-called much longer lifespans of CFC's (home use) and
LED's are B.S. The electronics to support them burn out in as little
as 1500 hours, especially the crap coming in from China. Is anyone
going to "repair" a disposable fixture? No.