Comet Over Cottonwood
Hartley 2, the 103rd comet to have its periodic orbit determined (103P), is a Jupiter-family comet discovered in March 1986 by Malcolm Hartley from Siding Spring Observatory in NSW, Australia. It returned to perihelion in 1991, 1997, 2004 and its latest apparition in 2010. This latest return has the been the most favorable of all in terms of its visibility from Earth, being glimpsed with the naked eye from very dark sky sites, and having passed a mere 11 million miles (0.12 AU) from the Earth on October 20th. According to the photographer “ I went out into rural NE Kansas on the morning of Hartley 2’s closest approach to Earth, and made this image of the fast-moving comet in the heart of Auriga above an autumn Cottonwood tree. The sky was very clear, and the atmospheric seeing was excellent, allowing for the sharp recording of star images in this rich region of the winter Milky Way. Open star clusters M37 and M38 are visible at left, as well as the faint red of emission nebulae – brilliant Capella (Alpha Aurigae) is at right. I used an 85mm lens for my final exposure of Hartley 2 just before the onset of morning twilight. It is a 254 second exposure @ f/2.8 at ISO 800, and during the final seconds of the exposure, the aperture was stopped to f/16 and the focus shifted to the Cottonwood trees which were illuminated with an 800,000 candlepower flashlight.” Click on the second photo to see a wider photograph of the same view.