Observing rainbows

Although most of our work in Astronomy 110 Lab is related to astronomical phenomena observed when the sky is dark, there are two exceptions. One is obvious: we will try to observe the Sun, which is the star closest to us. The other is perhaps a bit less obvious: we want to observe rainbows, which are the spectrum of the Sun produced by the refraction of solar light within raindrops. Rainbows are quite frequent in Honolulu, so we can try to collect empirical data which we can later use to understand the basic geometry of this natural "light show".

So whenever you see a rainbow, please stop for a few minutes, get your log book if available, or at least get paper and pen, write down date, time, and location, observe carefully, and try to answer the following questions.

Making sense out of it

If we are lucky, by the end of the semester we will have collected a variety of rainbow observations. Then we will devote part of one lecture to compare all these rainbow observations and explain the measured properties and the correlations between them.


Roberto H. Méndez (mendez@ifa.hawaii.edu)

Last modified: September 12, 2005