An Eclipse-created Monochromatic Rainbow

During this past May 20, 2012, the citizens of the US experienced the second biggest astronomical event of the year (the first being the transit of Venus in June).  People were concentrating their eyes, cameras, and telescopes at the moon as it slowly moved in front of the sun. The highlight of the event was the annular eclipse in the western part of the US. People further away from this annular path were treated to a partial eclipse. But a very select few in the Midwest experienced a rarer visual spectre, a rainbow. But not just any rainbow. It was a monochromatic rainbow from an eclipsed sun.

To create a monochromatic rainbow, the sun has to be near sunset so that mainly red light shines through. On the map, the eclipse was occurring during sunset in areas between the far left and far right red lines.  Next, if too much of the sun is eclipsed, there will not be enough light at sunset to create the already faint monochromatic rainbow. Areas below the light blue line have more than 80% of the sun blocked. The dark blue line is the path where an annular eclipse could be viewed. Finally, you need rain to create a rainbow but the storm should have a distinctive western edge were the sunset sun can shine through. The only place which all 3 elements is over the midwest (upper peninsula of Michigan, Illinois, and eastern Missouri). The regions in Ohio could have it but its likely that not much of the sun would be eclipsed at sunset. 

The photo above is a mosaic of frames from a video capture of the monochromatic rainbow over the Chicago skyline. I wish i could have gotten a better shot of it with my camera but its the best I could do.