Comet C/2013 US10 Catalina shows two spectacular tails and a bright aqua coma this morning (Dec. 6) . The dust tail, made
of dust boiled off the comet during it recent close approach to the sun, points to the southeast. Sunlight pushes the dust away
from the coma. The gas tail is made of gases such as carbon monoxide that fluoresce in solar ultraviolet light.
Credit: Michael Jaeger
http://astrobob.areavoices.com/2015/12/06/comet-catalina-impresses-see-the-moon-cover-venus-monday/