When light from the moon hits ice crystals in our upper atmosphere, the light diffracts in much the same way as sunlight does to create rainbows. Since these ice crystals typically have the same structure (a hexagonal shape) the size of the halo is always the same size, 46˚ in diameter. Accompanying this Lunar Halo is also a Moon Corona (the smaller, brighter circle). Moon Coronas are caused by a thin layer of clouds present in the upper atmosphere. These objects are only a few degrees in size. Looking closely at the very center of the image, there is an extremely bright and small circle. Zooming in on this area reveals the full moon, only 0.5˚ in size. In this image, the moon is in the constellation of Gemini. Within the lunar halo (to the lower left of the moon) is Mars. Location: Friend's Creek, IL Date: 2010-01-28 Camera: Canon XSi (Hap Griffin modified) Lens: Sigma 10mm f/2.8 Fisheye Mount: Still Tripod Shot: 1x15 seconds, 1x6 seconds, 1x2.5 seconds, 1x1/1600th second. All at f/4 @ ISO 200 Processing: Photoshop
Special Thanks to Michelle M. for her assistance on that cold, cold night! Location: Castlewood Canyon State Park, CO Date: 2010-12-21 Camera: Canon XSi (modified) Lens: Canon 200mm f/2.8L Extender: Canon 2x II EF Telextender Mount: Autotrac Shot: 3.2secs for Moon and 8sec for Stars f/5.6 ISO 100 Processing: Photoshop
Special Thanks to Michelle M. for her assistance on that cold, cold night! Location: Castlewood Canyon State Park, CO Date: 2010-12-21 Camera: Canon XSi (modified) Lens: Canon 200mm f/2.8L Extender: Canon 2x II EF Telextender Mount: Autotrac Shot: Ranging from 1/1250th sec to 3.2 secs @f/5.6 ISO 100 Processing: Photoshop
