Coronas Around the Moon
February 16, 2014
Photographer: Michael Grossmann; Michael's Web site
Summary Author: Michael Grossmann; Jim Foster
Sometimes you can see colored rings around the Moon or the Sun. These corona rings lie very close to the lunar/solar disk and result from diffraction of light through cloud droplets. The rings featured here were observed through a thin altostratus cloud around the half- illuminated Moon (quarter phase), from Kampfelbach, Germany, on the evening of December 9, 2013. It's possible to see distinct multiple rings if the droplets are of similar sizes -- a long exposure time brings out more color in a photograph. Each successive ring outward from the Moon becomes dimmer as the light source is further removed. Note also the scratch-like star trails.
Photo details: Canon EOS 60d camera; F/5; f/96mm; ISO 250; t=1/400 - 13 sec. exposure; 6 images generated with Photoshop.