Ivo -
From this listpost, I was hoping to drum up a couple of Utah and/or Salt Lake rainbow photos to add to the page.
Do you or other list members have suggestions of a favorite location to view/photograph rainbows from, in the Salt Lake Valley?
I don't think it's a matter of location; it's a matter of having a prepared mind during a favorable time window and keeping a camera handy. Topography plays a role - on the Wasatch Front that seems to favor spring. Personally, I've always seen them when standing or driving along 11th Avenue above the cemetry or for many years, when I was working on the 15th floor on the south side of a downtown office building. But, that is just where I live and work. Once you understand the geometry involved, I'm sure there are many other locations throughout Salt Lake, Davis and Utah counties that are just as good, for example your west bench Herriman description. I got started on this after deciding I wanted to capture some of these spring rainbows with a camera.
I was not as clear on the specifics . . . particularly with regard to the formation of secondary rainbows.
The secondary rainbows are at 52 degrees. In Salt Lake, I've only noticed them (and their reversed order spectra) during a near sunset scenario, when a near full 42 degree (80 degree arc) rainbow is also visible. Typically in April or early May.
Wikipedia has a good article . . . including a ray diagram of the double reflection . . .
Looks like I need to revise the webdoc. The first draft said, "one refraction and two reflections." Then I settled on "three refractions". Which terminology is right?
I thought if I were asked to explain it to a school class or other group I might find myself . . . stammering quite a bit . . . Thanks for including the Descartes figure.
I'm still unclear on how a side angle view works in three dimensions. Most frequently, I see rainbows when standing to the northwest of the rainbows' apparent position, which isn't what Descartes' figure shows. Glad you enjoyed the webdoc. Mothers with children under 8 seem to really get excited about this one for some reason. Guess it's something cool to do with the kids outdoors. - Kurt ____________________________________________________________________________________ Never miss a thing. Make Yahoo your home page. http://www.yahoo.com/r/hs