As some interesting posts have appeared (and some strange ones), I will
add the following:

Twilight.
Information of twilight can be found here
http://www.bbc.co.uk/dna/h2g2/A4149452

As to twilight at my location in midsummer, the following is a rough
guide (in BST rounded to nearest 30 minutes or so).

Sunset 2230
Civil twilight 2230 - 0030
Nautical twilight 0030 - 0200
Civil twilight 0200 - 0400
Sunrise 0400

Thus it never gets dark at this time of year.

The photograph.
The image which prompted my original post was one of a series I made for
purposes unrelated to my meteo site and it showed an effect which looks
rather like "a small sunset in the north at midnight".
It was not intended as simply 'a picture of twilight' (although twilight
was unavoidable) as twilight may be seen to varying degrees throughout
the world and is not normally considered photogenic.

The effect depicted cannot be seen from southern england, flat horizons
or not (nor does nautical twilight last all night there). Similarly, it
cannot be seen from the south midlands of england (where I used to live)
or the north coast of norfolk (where I spent a lot of time). The only
glow in the sky in the south midlands was from the combined effect of
far too much street lighting!

It is fair to say that the meagre lighting of the small town of
Peterhead contributed little to the effect in the photograph (which was
mostly over the sea).

Noctilucent cloud.
I have never (previously) heard of this, and never knowingly seen it. I
can deduce some of the definition from 'nocti' and 'lucent' of course,
but have no idea if it really exists.


The obejective (here) was simply to share a 'pretty moment'. The
photograph does not convey what it was like to 'be there' but then they
hardly ever do.

I was out last night/this morning collecting photographs of the full
moon (not worth the effort) and of the sunrise (ditto). There was no
repeat performance of the northern glow - too much cloud.

I may change the pic in a few days to one taken at about the same time
showing the moon and a lighthouse - for those who like moons and
lighthouses (-:


--
Gianna Stefani

www.buchan-meteo.org.uk