BlueLightning wrote:
I sure saw a glow in the northern sky last night.

Around 2:30am, it was before dawn

The sky looked almost electrically charged, but not moving or changing
like northern lights. Don't normally see northern lights anyway, since
i'm in south-west england

I speculated it might have been high altitude clouds with the bright
moon shining off


There was a nice display of NLC at 2am with the northern horizon aglow.
I think you are describing the same (51.5°N).

Felly sgrifennodd Roger Smith :
Astronomical twilight does not end until the sun is 12 deg below the
horizon, so at the summer solstice it lasts all night at latitudes north of
54.5 deg.

Unless definitions have changed, I think that's a little confused.

Civil twilight: 0-6 degrees below
Marine twilight: 6-12 degrees below
Astronomical twilight: 12-18 degrees below

Even the Lizard peninsula experiences astronomical twilight all night at
this time of year (by about 1.5 degrees). Gianna gets marine twilight all
night (sun is about 9 degrees below) and shetland gets civil (terrestrial
I think I read it as) twilight all night.

When I lived between Aberdeen and Peterhead, I remember walking on Forvie
Sands at midnight (local: i.e. about 1:08 am). A full moon was shining, but
based on the shadow cast, the full moon was giving less light than the
sun.

Adrian

--
Adrian Shaw ais@
Adran Cyfrifiadureg, Prifysgol Cymru, aber.
Aberystwyth, Ceredigion, Cymru ac.
http://users.aber.ac.uk/ais uk

"Adrian D. Shaw" wrote in message
...
Felly sgrifennodd Roger Smith :
Astronomical twilight does not end until the sun is 12 deg below the
horizon, so at the summer solstice it lasts all night at latitudes north
of
54.5 deg.

Unless definitions have changed, I think that's a little confused.

Civil twilight: 0-6 degrees below
Marine twilight: 6-12 degrees below
Astronomical twilight: 12-18 degrees below

Even the Lizard peninsula experiences astronomical twilight all night at
this time of year (by about 1.5 degrees). Gianna gets marine twilight all
night (sun is about 9 degrees below) and shetland gets civil (terrestrial
I think I read it as) twilight all night.

When I lived between Aberdeen and Peterhead, I remember walking on Forvie
Sands at midnight (local: i.e. about 1:08 am). A full moon was shining,
but
based on the shadow cast, the full moon was giving less light than the
sun.

Adrian

--
Sorry Adrian, my mistake - carelessness, not ignorance. All of the UK (ie
anywhere north of 48.5 deg) is afflicted by this phenomenon at this time of
year.

Regards, Roger