LPA Field Trip Apr 15-18, 2011 - Led by Bill Sutton and Sue Craft
Last fall, Bill had an idea… let’s go to Yosemite to capture the Moonbow! By planning over 6 months in advance, most of the group got a sweet deal at Yosemite Lodge. Book early, stay in the park, remember that the tent cabins have no power to charge your batteries, and that the shuttle stops running at 10pm so you want to be within walking distance of the waterfalls. Parking was a bit tight in April and the number of visitors is still very low.
Moonbows, also known as lunar rainbows, are a phenomenon that only occur about three or four times a year, and are only visible for about one to two hours each time they occur. Moonbows usually only occur during the months of April, May and June and are dependent upon having bright moonlight, the moon must have risen above the south rim of the Yosemite Valley, sufficient mist and spray from the snowmelt runoff, clear skies, and the moon at a direction toward the base of the falls at or near a “rainbow angle” of 42°. When the conditions are right, what appears as a “white”, “grey” or “silvery” streak to the human eye will reveal a photograph with the full spectrum of the rainbow’s colors.