APOD3.3 Comet McNaught from New STEREO Satellite

The brightest comet (magnitude -5) since comet Ikeya-Seki in 1965 (magnitude -7) has rounded the sun and is heading away from earth. People in the southern hemisphere can still see the comet and it has gotten so bright that you could see it in broad daylight if you block the sun with your hand.
This picture of the comet was taken by a new satellite that opened on January 11. The comet's ion tail is clearly seen being swept by the solar winds, while the coma is so bright that it saturates. In the picture the tail spans 7 degrees.