The Machinery of Night

Foto Friday: Bay of Rainbows

Rainbow over Hilo Bay, HI, Sep. 1995

This bay is not on the Moon, but in Hilo, Hawaii. Note the double rainbow. This was taken (I'm pretty sure) from the back of the Hilo Bay Hotel, aka Uncle Billy's, a funky, kitschy hotel on Banyan Drive in Hilo. Long may it wave.

The sky between the two rainbows is supposed to be noticeably darker than the sky within the primary and outside the secondary, but you can't really tell that here.

Rainbow over Coconut Island, Hilo, HI, Sep. 1995

Here it is a few minutes later. Note how unusually low it is! Rainbows always occur opposite the sun. It's not unusual for a storm to clear at sunset, say, leaving the sky clear in the west while the eastern sky is still black. Then, the sun is low and the rainbow is high.

But here the sun is high in the sky, shining almost straight down on the little rainstorm. In most cases the clouds would block the sun. You can only get this effect when the rain is very localized -- and then you have to be lucky.

Fred Schaaf's The Starry Room has a good chapter on rainbows, even though it's really a book about astronomy. (If I recall correctly, he has a list of the sorts of conditions under which you might see a rainbow. He left out one I saw in West Texas: a rainbow in virga -- the long tail of precipitation that hangs from a cloud, but evaporates before it hits the ground. I didn't have my camera out at the time, though.)

Another fun book is Rainbows, Halos, and Glories by Robert Greenler, which is apparently totally out of print and goes for ridiculous prices. Huh. Anyhow, many neat pictures of atmospheric phenomena in that bok.