There are some streetlamps at the end of Camden Road which consist of a pole
with a horizontal arm on top. The long end of the arm holds the main lamp:
the short end pointing the other way has a faint blue light on it. What's
that about?

In article , John Rowland
writes

There are some streetlamps at the end of Camden Road which consist of a pole
with a horizontal arm on top. The long end of the arm holds the main lamp:
the short end pointing the other way has a faint blue light on it. What's
that about?

Chavved-up streetlights?

They've also been installed along the recently refurbished Edge Lane
arterial road in Liverpool, but these have the blue LED at the top of
the vertical pole.

All the 1L Saxo boys with stick-on tinted windows and tin-can exhausts
must be made up.

--
(\__/)
(='.'=) Bunny says Windows 7 is Vi$ta reloaded.
(")_(") http://imgs.xkcd.com/comics/windows_7.png

On Feb 28, 8:50*am, Mike Tomlinson wrote:
In article , John Rowland
writes



There are some streetlamps at the end of Camden Road which consist of a pole
with a horizontal arm on top. The long end of the arm holds the main lamp:
the short end pointing the other way has a faint blue light on it. What's
that about?

Chavved-up streetlights?

They've also been installed along the recently refurbished Edge Lane
arterial road in Liverpool, but these have the blue LED at the top of
the vertical pole.

All the 1L Saxo boys with stick-on tinted windows and tin-can exhausts
must be made up.

A wild guess: maybe it's to do with distinguishing between power off
and the lamp failing?

Mike Tomlinson wrote:
In article , John Rowland
writes

There are some streetlamps at the end of Camden Road which consist
of a pole with a horizontal arm on top. The long end of the arm
holds the main lamp: the short end pointing the other way has a
faint blue light on it. What's that about?

Chavved-up streetlights?

Not half as chavved-up as the one in Crowndale Road, just down from Koko.
Today there were two pairs of Rockports, tied together by the laces, hanging
from the horizontal lamp-arm. Must have taken some very accurate throwing to
get them up there!

In message
, MIG
writes

[ blue lights on street lamps]

A wild guess: maybe it's to do with distinguishing between power off
and the lamp failing?

That's possible, but I posted here a long time ago about new street
lamps on the South Circular that have a very distinct (and not at all
feint) blue lens pointing upwards.

This is very obvious from above, but can only be seen from ground level
if standing a very long way from the lamp post concerned.

If it is some sort of pilot lamp, it seems very badly positioned.

I didn't receive any plausible replies when I posted about this, but I
have seen it suggested that modern "cobra" street lamps are so well
designed to prevent night-sky pollution, that they need an upward aspect
in blue in order to delineate the location of major roads for aircraft
that, due to failure of automatic systems, are having to rely on visual
navigation at night.

I have no idea whether this is true (despite quite a lot of fruitless
research), but I have noticed that most of these upwardly-directed blue
lights are on major trunk routes in the capital (specifically on TfL red
routes).

All of the new red-route lamposts around here also have two brackets,
about two metres apart vertically, with eyes that seem to be designed to
tie banners. No banner has ever appeared - if the only one that ever
does is "London Olympics 2012", I shall be even more despondent about
the hidden costs of "the games" - an awful lot of welded steel has gone
into these appendages.
--
Paul Terry

Paul Terry wrote:
In message
,
MIG writes

[ blue lights on street lamps]

A wild guess: maybe it's to do with distinguishing between power off
and the lamp failing?

That's possible, but I posted here a long time ago about new street
lamps on the South Circular that have a very distinct (and not at all
feint) blue lens pointing upwards.

This is very obvious from above, but can only be seen from ground
level if standing a very long way from the lamp post concerned.

If it is some sort of pilot lamp, it seems very badly positioned.

I didn't receive any plausible replies when I posted about this, but I
have seen it suggested that modern "cobra" street lamps are so well
designed to prevent night-sky pollution, that they need an upward
aspect in blue in order to delineate the location of major roads for
aircraft that, due to failure of automatic systems, are having to
rely on visual navigation at night.

I have no idea whether this is true (despite quite a lot of fruitless
research), but I have noticed that most of these upwardly-directed
blue lights are on major trunk routes in the capital (specifically on
TfL red routes).

All of the new red-route lamposts around here also have two brackets,
about two metres apart vertically, with eyes that seem to be designed
to tie banners. No banner has ever appeared - if the only one that
ever does is "London Olympics 2012", I shall be even more despondent
about the hidden costs of "the games" - an awful lot of welded steel
has gone into these appendages.

Possibly they're markers for police and other emergency helicopters?

"Brimstone" wrote in message
...
Paul Terry wrote:
In message
,
MIG writes

[ blue lights on street lamps]

A wild guess: maybe it's to do with distinguishing between power off
and the lamp failing?

That's possible, but I posted here a long time ago about new street
lamps on the South Circular that have a very distinct (and not at all
feint) blue lens pointing upwards.

This is very obvious from above, but can only be seen from ground
level if standing a very long way from the lamp post concerned.

If it is some sort of pilot lamp, it seems very badly positioned.

I didn't receive any plausible replies when I posted about this, but I
have seen it suggested that modern "cobra" street lamps are so well
designed to prevent night-sky pollution, that they need an upward
aspect in blue in order to delineate the location of major roads for
aircraft that, due to failure of automatic systems, are having to
rely on visual navigation at night.

Lit roads are perfectly visible even if you can't see individual lamps.
Besides, there are usually much better markers than roads - sports stadia
are very distinctive, for example.

....
Possibly they're markers for police and other emergency helicopters?

That sounds the most likely. They would want to know where the posts are
when trying to land on a road.

Colin Bignell

"Paul Terry" wrote
All of the new red-route lamposts around here also have two brackets,
about two metres apart vertically, with eyes that seem to be designed to
tie banners. No banner has ever appeared - if the only one that ever does
is "London Olympics 2012", I shall be even more despondent about the
hidden costs of "the games" - an awful lot of welded steel has gone into
these appendages.

Be grateful for the emptiness - in my neck of the woods, they all have
McDonalds adverts - either way, don't blame the olympics - it's the local
council trying raise revenue.
--

Andrew
http://www.flayme.com/

"If A is success in life, then A = x + y + z.
Work is x; y is play; and z is keeping your mouth shut." ~ Albert Einstein

"nightjar" cpb@insert my surname here wrote:

Possibly they're markers for police and other emergency helicopters?

That sounds the most likely. They would want to know where the posts are
when trying to land on a road.

Hmm, which road in Camden Town do you think you could land a helicopter
on?

In message , nightjar
writes

"Brimstone" wrote in message
...

Possibly they're markers for police and other emergency helicopters?

That sounds the most likely. They would want to know where the posts are
when trying to land on a road.

You'd never land a helicopter on the road concerned. The south circular
in these parts is a narrow single-carriageway road, with buildings right
up to the pavement.

Also, most buildings are higher than the lamp posts - I can clearly see
the upward-pointing blue lights from my second floor because they are
just below window level. They are very hard to see from pavement level.

I wondered if they could be for aircraft recognition because we are
close to the spot where the Battersea heliport flight paths cross the
incoming Heathrow flight path, albeit at a lower level. But if these
lights are appearing in other parts of London, that would not be the
reason and, as has been pointed out, there is plenty of light diffusion
on main roads to see their positions from the air.

Given that the blue light is in the position normally occupied by the
dusk - dawn light sensor, I wonder if the blue glow is some way of
making the sensor more accurate in densely-lit areas?
--
Paul Terry