In reply to Iain Thow:
Agree, I see brocken spectre's several times a year, once you know the required conditions you have a good chance of generating them. Only ever seen a fog-bow, once and like Robert with a Brocken within it.
Other interesting light events I've encountered is a moon-bow (rainbow by moonlight), mother of pearl cloud and a perfectly horizontal rainbow (i.e. without the bow) across the surface of a loch during heavy rain, not only were there rain-drops but the rain was so hard there were splash droplets being ejected upwards from the loch, plus spindrift being whipped by the wind.
Never seen a green flash as the sun dips below the horizon over the ocean.
Wonder if anyone has ever seen a brocken spectra or fog-bow by moonlight............