An image of comet Hartley 2 taken on Sept. 3, 2010 at the 2.1 meter telescope at the Kitt Peak National Observatory near Tucson, Ariz. In this image, red denotes regions where CN gas is more abundant. The image is enhanced by removing the underlying background in order to highlight the jet feature present. North is up and east is to the left. The image is nearly 50,000 miles across and the comet nucleus which is not resolved is at the center. The red streaks are star trails. Credit: PSI