Astronomy Magazine: LED lighting the WORST for light pollution

Not because they point them all skyward, but because their spectrum washes across the ENTIRE visible range. There are no hard, discrete line outputs that can be filtered. If the MORON politicians can be persuaded to keep them as DIRECTIONAL and dim as is needed, that might mitigate some of the coming problem.

On Wed, 30 Aug 2017 16:54:03 -0700 (PDT), RichA
wrote:

Not because they point them all skyward, but because their spectrum washes across the ENTIRE visible range. There are no hard, discrete line outputs that can be filtered. If the MORON politicians can be persuaded to keep them as DIRECTIONAL and dim as is needed, that might mitigate some of the coming problem.

They are the best for light pollution, and energy efficiency, if they
are properly implemented, however.

But it doesn't really matter for serious astronomy, since very few
important observatories are significantly impacted by light pollution,
or likely to be.

On 31/08/2017 04:31, Chris L Peterson wrote:
On Wed, 30 Aug 2017 16:54:03 -0700 (PDT), RichA
wrote:

Not because they point them all skyward, but because their spectrum washes across the ENTIRE visible range. There are no hard, discrete line outputs that can be filtered. If the MORON politicians can be persuaded to keep them as DIRECTIONAL and dim as is needed, that might mitigate some of the coming problem.

They are the best for light pollution, and energy efficiency, if they
are properly implemented, however.

Not true yet. Low pressure sodium gas discharge still beats the best
production LEDs even today and is easily filtered. It is mandated in
zones around major optical observatories along with full cutoff
sheilding and time switched to drop them off entirely late at night.

This is also true of some new LED systems. Dimmer or off very late.

But it doesn't really matter for serious astronomy, since very few
important observatories are significantly impacted by light pollution,
or likely to be.

Encrouchment of light at many of the Northern hemisphere observatory
sites is getting to be a problem. Palomar is all but unusable now. Las
Palmas is headed that way - skies noticeably worse than in the 1980's.

http://web.archive.org/web/200201020...gon/apagon.htm

Unfortunately it doesn't save the spectrum graphs.

Chilean skies are still pristine and truly dark.

--
Regards,
Martin Brown

On Thu, 31 Aug 2017 08:36:48 +0100, Martin Brown
wrote:

On 31/08/2017 04:31, Chris L Peterson wrote:
On Wed, 30 Aug 2017 16:54:03 -0700 (PDT), RichA
wrote:

Not because they point them all skyward, but because their spectrum washes across the ENTIRE visible range. There are no hard, discrete line outputs that can be filtered. If the MORON politicians can be persuaded to keep them as DIRECTIONAL and dim as is needed, that might mitigate some of the coming problem.

They are the best for light pollution, and energy efficiency, if they
are properly implemented, however.

Not true yet. Low pressure sodium gas discharge still beats the best
production LEDs even today and is easily filtered. It is mandated in
zones around major optical observatories along with full cutoff
sheilding and time switched to drop them off entirely late at night.

Nope. LPS is less energy efficient because it can't be dimmed. And
that precludes turning them off in most places. Depending on the
relationships between cities and observatories, special lighting may
be agreed upon. But certainly, most observatories are not strongly
impacted by light pollution, and it is horrible public policy to
design lighting standards around astronomical needs.

But it doesn't really matter for serious astronomy, since very few
important observatories are significantly impacted by light pollution,
or likely to be.

Encrouchment of light at many of the Northern hemisphere observatory
sites is getting to be a problem. Palomar is all but unusable now. Las
Palmas is headed that way - skies noticeably worse than in the 1980's.

Palomar is more productive than ever. A great many usages don't
require dark skies at all. With adaptive optics, a huge number of
options exist for utilizing the ability of large mirrors to collect
high resolution imagery, often of bright targets.

On Wednesday, 30 August 2017 23:31:14 UTC-4, Chris L Peterson wrote:
On Wed, 30 Aug 2017 16:54:03 -0700 (PDT), RichA
wrote:

Not because they point them all skyward, but because their spectrum washes across the ENTIRE visible range. There are no hard, discrete line outputs that can be filtered. If the MORON politicians can be persuaded to keep them as DIRECTIONAL and dim as is needed, that might mitigate some of the coming problem.

They are the best for light pollution, and energy efficiency, if they
are properly implemented, however.

But it doesn't really matter for serious astronomy, since very few
important observatories are significantly impacted by light pollution,
or likely to be.

For now. BTw, what in the world would make you think, after 100 years of bad outdoor lighting, that they would be implemented properly, or are you just Hell-bent on being a contrarian?

On Thu, 31 Aug 2017 17:01:44 -0700 (PDT), RichA
wrote:

On Wednesday, 30 August 2017 23:31:14 UTC-4, Chris L Peterson wrote:
On Wed, 30 Aug 2017 16:54:03 -0700 (PDT), RichA
wrote:

Not because they point them all skyward, but because their spectrum washes across the ENTIRE visible range. There are no hard, discrete line outputs that can be filtered. If the MORON politicians can be persuaded to keep them as DIRECTIONAL and dim as is needed, that might mitigate some of the coming problem.

They are the best for light pollution, and energy efficiency, if they
are properly implemented, however.

But it doesn't really matter for serious astronomy, since very few
important observatories are significantly impacted by light pollution,
or likely to be.

For now. BTw, what in the world would make you think, after 100 years of bad outdoor lighting, that they would be implemented properly, or are you just Hell-bent on being a contrarian?

Well, in actual practice, a great many places are incorporating much
better lighting design as they switch to LEDs. There are several
reasons for that, such as the fact that the luminaires are designed
with shielding from the beginning, and part of the sales pitch is the
reduced cost associated with intelligent control, which is often sold
as part of the entire package.

Chris L Peterson wrote:
On Thu, 31 Aug 2017 08:36:48 +0100, Martin Brown
wrote:

On 31/08/2017 04:31, Chris L Peterson wrote:
On Wed, 30 Aug 2017 16:54:03 -0700 (PDT), RichA
wrote:

Not because they point them all skyward, but because their spectrum
washes across the ENTIRE visible range. There are no hard, discrete
line outputs that can be filtered. If the MORON politicians can be
persuaded to keep them as DIRECTIONAL and dim as is needed, that might
mitigate some of the coming problem.

They are the best for light pollution, and energy efficiency, if they
are properly implemented, however.

Not true yet. Low pressure sodium gas discharge still beats the best
production LEDs even today and is easily filtered. It is mandated in
zones around major optical observatories along with full cutoff
sheilding and time switched to drop them off entirely late at night.

Nope. LPS is less energy efficient because it can't be dimmed. And
that precludes turning them off in most places. Depending on the
relationships between cities and observatories, special lighting may
be agreed upon. But certainly, most observatories are not strongly
impacted by light pollution, and it is horrible public policy to
design lighting standards around astronomical needs.

But it doesn't really matter for serious astronomy, since very few
important observatories are significantly impacted by light pollution,
or likely to be.

Encrouchment of light at many of the Northern hemisphere observatory
sites is getting to be a problem. Palomar is all but unusable now. Las
Palmas is headed that way - skies noticeably worse than in the 1980's.

Palomar is more productive than ever. A great many usages don't
require dark skies at all. With adaptive optics, a huge number of
options exist for utilizing the ability of large mirrors to collect
high resolution imagery, often of bright targets.


Tha sodium light almost opposite my house is turned off every day (at least
it is now the council repaired the daylight sensor).
So why couldn't it be turned off during darkness?

On Fri, 1 Sep 2017 16:34:37 -0000 (UTC), Mike Collins
wrote:

Tha sodium light almost opposite my house is turned off every day (at least
it is now the council repaired the daylight sensor).
So why couldn't it be turned off during darkness?

In theory, it could. But those old systems are not set up for that
kind of control, and in many cases "off" is not what is needed, as
opposed to "dim".

If an area is going to switch over to smart lighting, they're likely
to do it alongside the replacement of the fixtures and sources at the
same time.

Chris L Peterson wrote:
On Fri, 1 Sep 2017 16:34:37 -0000 (UTC), Mike Collins
wrote:

Tha sodium light almost opposite my house is turned off every day (at least
it is now the council repaired the daylight sensor).
So why couldn't it be turned off during darkness?

In theory, it could. But those old systems are not set up for that
kind of control, and in many cases "off" is not what is needed, as
opposed to "dim".

If an area is going to switch over to smart lighting, they're likely
to do it alongside the replacement of the fixtures and sources at the
same time.


This particular light is decades old. The daylight sensor is an add on. I
phoned the council to repair it when the daylight sensor broke hoping they
would replace the whole lamp post. I also reported that it's leaning after
a car hit it but they just ignored that. I want a properly shielded LED
lamp. But all they did was replace the sensor.

On Fri, 1 Sep 2017 23:33:13 -0000 (UTC), Mike Collins
wrote:

Chris L Peterson wrote:
On Fri, 1 Sep 2017 16:34:37 -0000 (UTC), Mike Collins
wrote:

Tha sodium light almost opposite my house is turned off every day (at least
it is now the council repaired the daylight sensor).
So why couldn't it be turned off during darkness?

In theory, it could. But those old systems are not set up for that
kind of control, and in many cases "off" is not what is needed, as
opposed to "dim".

If an area is going to switch over to smart lighting, they're likely
to do it alongside the replacement of the fixtures and sources at the
same time.


This particular light is decades old. The daylight sensor is an add on. I
phoned the council to repair it when the daylight sensor broke hoping they
would replace the whole lamp post. I also reported that it's leaning after
a car hit it but they just ignored that. I want a properly shielded LED
lamp. But all they did was replace the sensor.

Sure. But the smart lighting systems we're starting to see (especially
in Europe) are networked. Every streetlight is individually
controllable.