Lowell astronomer Matthew Knight helped obtain this image below of Comet ISON with the Hubble Space Telescope. To the right is an enhanced image of the original photo, with a scale in miles and kilometers.
The above photo of Comet ISON was taken on April 10, 2013 when it was at a distance of around 4.151+ AU (386+ million miles, 621+ million kilometers) from the sun. A F606W (V) filter was used, which gives the photo its vivid blue color. According to the official Hubble Space Telescope website, Comet ISON is “hurtling toward the sun at approximately 47,000 miles per hour.” It should reach perihelion (the closest approach to the sun) on November 28, 2013.
As of April 23, 2013, Comet ISON is not visible to the naked eye. It will become visible to the naked eye later on this year as it becomes closer to the sun.
Size: 3-4 miles across
Discovered: September 21, 2012
Speed: 47,000 mph toward the sun
Distance from sun on April 10, 2013: 4.151 AU (date image was taken)
Distance from Earth on April 10, 2013: 4.241 AU
Distance from sun on April 23, 2013: 3.995 AU
Distance from Earth on April 23, 2013 4.299 AU
Perihelion: November 28, 2013
URL for public domain photo downloads: http://hubblesite.org/newscenter/archive/releases/2013/14/image/a/
NASA, ESA, J.-Y. Li (Planetary Science Institute), and the Hubble Comet ISON Imaging Science Team
The photo image was created from Hubble data from proposal 13198: J.-Y. Li (Planetary Science Institute), P. Lamy (Laboratoire d’Astrophysique de Marseille), H. Weaver (JHU/APL), M. A’Hearn and M. Kelley (University of Maryland), M. Knight (Lowell Observatory), T. Farnham (University of Maryland), and I. Toth (Hungarian Academy of Sciences).