POTD Day 217: Blue Hour -sooo cool!

I am taking a GREAT online photog class from Kent Weakley called Night Photography. So far, I am LOVING it. He explains things so well and gives really detailed and thoughtful and consistent feedback to the participants.

Anyway, the first topic was about Blue Hour. I had never heard of it before..but it is really amazing. There is a "golden" (or BLUE) period of time when the sun isn't all the way up or all the way down and the light bounces off the atmosphere and back onto the earth. During that period, and with the correct camera settings, the sky will be different variations of blue. I took lots of shots tonight between 4:15 and 5:30 or so tonight just in my backyard to test the technique and effect. The first shot was taken at the very beginning of "blue hour" and the second was well into it. I will have to get a great shot of the Seattle skyline or an outside Christmas tree that is all lit up during this time and use this technique. Have you heard of this before or am I the only one who has now been enlightened?