May 16, 2015
When we were sailing in the Marquesas back at the beginning of this cruise, I was surprised one night by a star that had vibrant colors that were constantly changing. I looked at it through the binoculars and as I wiggled the binoculars around, the colors became very pronounced.
The explanation, it turns out, is that our atmosphere is refracting the light, causing us to see the star jumping around, twinkling or changing color. The lower in the sky the star is, the more atmosphere the light must pass through to get to our eyes, and the more the light is refracted. There’s a good explanation here.
I saw a very colorful star on our last passage and I decided to try to get a picture. By wiggling the camera, I could get the star to draw a pattern and the separate colors became very distinct.
It turns out, this doesn’t usually happen with planets, just stars, which are more of a point-source of light. Here’s an example of a planet…
OK, reading about this might have taken the mystery out of the colorful stars for me, but they’re still beautiful! -Rich
