Dr Ivan D. Reid wrote:
On Fri, 27 Oct 2006 18:19:04 +0100, Paul Terry
wrote in :
I *think* this curious question may be related to transport ...

Our local part of the South Circular had new streetlamps fitted by TfL
about a year ago. The lamp posts have two brackets (presumably for
hanging, say, "London Olympics" banners); the lamp housings are circular
and on the top of each is raised dome. I thought nothing of the latter
until, getting up early a few days ago, I looked out of our loft window
and saw that the domes are actually skyward-pointing bright blue lights
that were illuminated on this one occasion.

It seems to be the "done thing" to illuminate everything with blue
LEDs, now that they are available -- the refurbished Students' Onion building
at Brunel has them for no obvious reason.

It's to balance out the Glowing Orange Blob on top of Tower A.
I wonder if the Uni has an environmental policy at all?

Anyway, I much prefer the angle-dependent ones in the wall at the
entrance to the Heathrow tunnel.

Does anyone know what these lamps are for? The South Circular through
Putney and East Sheen is pretty much exactly on one of the incoming
Heathrow flight-paths ... but surely they wouldn't be some kind of
landing lights, as we are about 9 miles away from Heathrow.

Also streetlamps tend to be along roads, which tend to have bends...
how many of these lamps are there?

Do air ambulances have designated landing spots - could it indicate
something like that?

The colour's weird too - the human eye isn't very sensitive to blue,
so (per Watt) it seems a bad choice for something to be seen from a
distance, or in fog...

Hth

Henry