FreeLists / az-observing / [AZ-Observing] Re: iridescent green mother of pearl sky

["Tom Polakis" <polakis@xxxxxxx>]

Bill,

It's in your subject line; it sounds like iridescence, which shows up
often when there are sheared, wind-blown clouds present.  See the
Astronomy Picture of the Day from a couple months ago.

http://antwrp.gsfc.nasa.gov/apod/ap030311.html

They aren't all that rare.  I think they show up in middle-level clouds
more than cirrus, as they are due to diffraction around water droplets,
and not ice crystals.

Tom



> I would like an explanation please of the following.
>
> Saturday, May 2 at Kartchner Caverns State Park, was the middle of the
four day Astrofest with speakers and nightly star parties. Towards sunset
the sun was shining through high cirrus clouds. A large section of the
clouds southeast of the sun became incredibly brilliant mother of pearl
blue and rich aqua green.  This area was NOT 22* south of the sun and
absolutely NOT sundogs, nor were they in line to be sun pillars.  In fact
the phenomenon was not at all symmetrical.  What is this?
>
> Bill Peters
> afls@xxxxxxx
>
> --
> See message header for info on list archives or unsubscribing, and
please
> send personal replies to the author, not the list.
>


--
See message header for info on list archives or unsubscribing, and please 
send personal replies to the author, not the list.