In reply to UKC/UKH Articles:
Some pedantry follows ...
"Scientists and mountain photographers are divided as to how exactly alpenglow occurs: some believe it requires direct sunlight, others indirect - and some think it can occur in both circumstances. "
I don't think that is right -- there is disagreement in the definition of alpenglow, whether it is direct or indirect lighting, but how it occurs is understood for both definitions.
And anti-crepuscular rays can be near horizontal, and in the west, if you get up early enough