Correspondent Alan Garde sent in this picture of his accidental rainbow. He says:
"At this time of year the morning sun shines through the edge of our glass balustrade on the upstairs balcony and, courtesy of the massive A-Frame skylight through which I can view the moon and stars, shines on our Ikea poster of Amsterdam ..."
Dang that's good! Thanks Alan for sharing this unexpected rainbow. Click to embiggen.