Explanation: Comet Hale-Bopp, the Great Comet of 1997, was quite a sight. In the above photograph taken on 1997 April 6, Comet Hale-Bopp was imaged from the Indian Cove Campground in the Joshua Tree National Park in California , USA . A flashlight was used to momentarily illuminate foreground rocks in this six minute exposure. An impressive blue ion tail was visible above a sunlight-reflecting white dust tail . Comet Hale-Bopp remained visible to the unaided eye for over a year before returning to the outer Solar System and fading. As Comet ISON approaches the Sun this week , sky enthusiasts around the Earth are waiting to see if its tails will become even more spectacular than those displayed by Comet Hale-Bopp.

Happy Holidays: Free APOD 2014 Calendar in PDF format