apod
06-10-08, 01:51 PM
http://antwrp.gsfc.nasa.gov/apod/image/0806/circumhorizonarc_gitto.jpg (http://antwrp.gsfc.nasa.gov/apod/image/0806/circumhorizonarc_gitto_big.jpg) A Fire Rainbow Over New Jersey
Credit & Copyright: Paul Gitto (http://antwrp.gsfc.nasa.gov/apod/mailto: pg190 at Comcast dot net)(Arcturus Observatory)
Explanation: What is that inverted rainbow in the sky? Sometimes known as a fire rainbow for its flame-like appearance, a circumhorizon arc (http://en.wikipedia.org/wiki/Circumhorizon_arc) is created by ice, not fire. For a circumhorizon arc (http://www.atoptics.co.uk/halo/cha2.htm) to be visible, the Sun must be at least 58 degrees high in a sky where cirrus clouds (http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/cld/cldtyp/hgh/crs.rxml) are present. Furthermore, the numerous, flat, hexagonal ice-crystals (http://www.lsbu.ac.uk/water/ice1h.html) that compose the cirrus cloud (http://en.wikipedia.org/wiki/Cirrus_cloud) must be aligned horizontally (http://www.atoptics.co.uk/halo/platcol.htm) to properly refract sunlight (http://youtube.com/watch?v=U98KPM2b9IA) like a single gigantic prism (http://micro.magnet.fsu.edu/primer/java/scienceopticsu/newton/). Therefore, circumhorizon arcs (http://antwrp.gsfc.nasa.gov/apod/ap040804.html) are quite unusual to see. Pictured (http://cometman.com/Arcs/Circumhorizon-Arcs.html) above (http://cometman.com/Lightroom/CHA-05-28-2008/index.html), however, a rare fire rainbow (http://antwrp.gsfc.nasa.gov/apod/) was captured above trees in Whiting (http://en.wikipedia.org/wiki/Whiting%2C_New_Jersey), New Jersey (http://en.wikipedia.org/wiki/New_Jersey), USA (http://en.wikipedia.org/wiki/United_States) in late May (http://en.wikipedia.org/wiki/May_2008).
Source (http://antwrp.gsfc.nasa.gov/apod/ap080610.html)
Credit & Copyright: Paul Gitto (http://antwrp.gsfc.nasa.gov/apod/mailto: pg190 at Comcast dot net)(Arcturus Observatory)
Explanation: What is that inverted rainbow in the sky? Sometimes known as a fire rainbow for its flame-like appearance, a circumhorizon arc (http://en.wikipedia.org/wiki/Circumhorizon_arc) is created by ice, not fire. For a circumhorizon arc (http://www.atoptics.co.uk/halo/cha2.htm) to be visible, the Sun must be at least 58 degrees high in a sky where cirrus clouds (http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/cld/cldtyp/hgh/crs.rxml) are present. Furthermore, the numerous, flat, hexagonal ice-crystals (http://www.lsbu.ac.uk/water/ice1h.html) that compose the cirrus cloud (http://en.wikipedia.org/wiki/Cirrus_cloud) must be aligned horizontally (http://www.atoptics.co.uk/halo/platcol.htm) to properly refract sunlight (http://youtube.com/watch?v=U98KPM2b9IA) like a single gigantic prism (http://micro.magnet.fsu.edu/primer/java/scienceopticsu/newton/). Therefore, circumhorizon arcs (http://antwrp.gsfc.nasa.gov/apod/ap040804.html) are quite unusual to see. Pictured (http://cometman.com/Arcs/Circumhorizon-Arcs.html) above (http://cometman.com/Lightroom/CHA-05-28-2008/index.html), however, a rare fire rainbow (http://antwrp.gsfc.nasa.gov/apod/) was captured above trees in Whiting (http://en.wikipedia.org/wiki/Whiting%2C_New_Jersey), New Jersey (http://en.wikipedia.org/wiki/New_Jersey), USA (http://en.wikipedia.org/wiki/United_States) in late May (http://en.wikipedia.org/wiki/May_2008).
Source (http://antwrp.gsfc.nasa.gov/apod/ap080610.html)