"Bernard Burton" wrote in message
...
Roger,
To be illuminated by the sun at that time and in that location, they would
have to be at noctilucent cloud height, ca 80km, as any tropspheric clouds
would be in the earth's shadow, and appear black, or nearly so, even
cirrus
cloud.

--
Bernard Burton
Wokingham, Berkshire, UK.


Thanks Bernard. I did not have time to do my sums. Because of the clear
sky and the recent reports I was indeed glancing up for sight of noctilucent
clouds when I joined the motorway, but when I saw the illuminated streaks
low down in the north I felt unable to judge whether they were what I was
looking for.

Regards, Roger