nightjar wrote:

"Nick Maclaren" wrote in message
...

In article ,
Victoria Clare writes:
|
| Frankly, why not spend your money on a chocolate teapot? Equally
| useful, and rather tastier.
|
| Only if you live somewhere with streetlights!

Or where there is massive sky glow, which accounts for over 99%
(perhaps 99.9%) of the UK population. I don't think that there is
anywhere left in the south east or midlands where the sky glow isn't
oppressive, and precious few places outside those.

'Oppressive' is a very subjective assessment and quite different from
'useful for seeing by'. I've spent more than a few nights standing out in
the Sussex countryside without being able to see my hand in front of my
face, at least, not without night vision equipment.

For how long ? Most places I have been in the UK you can see well enough to
walk by sky glow even on a moonless night after only ten minutes. If you lack
the patience then yes it is too dark to see anything, but the eye is
tremendously adaptable if you give it time. Dark adapted an LED torch using
just 50uA current is usable (thats about 2 years of continuous light from AA
cells). Some modern torches for emergency use now incorporate LEDs on low
standby current as markers so that they can be found easily in the pitch
dark.

Even in remote arid regions and after the end of astronomical twilight I can
still see my hand in front of my face as a silhouette against the night sky.
It takes around half an hour for your eyes to become fully dark adapted.

Solar lighting is pretty much an expensive toy as presently sold to the
public. The most recent set of bankrupt stock I saw were still not worth
buying for the batteries they contained at 30% of rrp.

Regards,
Martin Brown