Strange sunset/sunrise calulation

[yjb]

Not sure how this is handled in the different OS environments, and if you can use this in Gamba's:

Determine the current offset from GMT
# date +%z
+0200

Determine the current timezone (in winter this will be CET for Europe)
# date +%Z
CEST

[RDNZL]

Have to check how we can make this work for non Europeans.