Comet Elenin (C/2010 X1) made its debut on December 10th when Leonid Elenin, an observer in Lyubertsy, Russia, remotely acquired four 4-minute-long images using an 18-inch (45-cm) telescope at the ISON-NM observatory near Mayhill, New Mexico. Follow-up images by Aleksei Sergeyev and Artyom Novichonok at Maidanak Observatory in Uzbekistan revealed more about the new find: it had a teardrop-shaped, very diffuse coma just 6 arc seconds across and a tiny tail.
What's gotten hearts beating a little faster since the discovery is that Comet Elenin is still more than 4 astronomical units (375 million miles) from the Sun and headed inbound. It's still early, and the calculated orbit is certain to change in the weeks ahead as more position measurements are made, but right now it appears that the comet's perihelion will occur well inside Earth's orbit, about 0.45 a.u. (42 million miles) from the Sun, next September 5th.
Right now, odds are that Comet Elenin will become an easy target for binoculars around mid-August and reach naked-eye visibility for a couple of weeks around perihelion. The comet's elongation from the Sun shrinks to just 1° following perihelion, but soon thereafter the comet gets enough separate to position itself nicely for viewing in the predawn sky.
Moreover, it's traveling very near the ecliptic plane, and as it sweeps close to the Sun its sky location won't stray far from the ecliptic until mid-September, when the path arcs slowly northwestward through Leo. That's a plus for sky watchers in the Northern Hemisphere.
Finally, because Comet Elenin passes between the Sun and Earth, there's a chance its dust tail might "light up" (via forward-scattered light) due to the large Sun-comet-Earth angle and put on a really good show. The last interloper to do this, Comet McNaught, dazzled southern sky gazers in January 2007.
Leonid Elenin - Leonid Elenin lives near Moscow and is an accomplished optician who likes to observe asteroids and variable stars.
Mr. Elenin wrote to us with this comment regarding the FLI MicroLine ML09000: "Thanks for you very reliable and sensitive camera! Your ML format was an excellent fit for our telescope in New Mexico".
The image below shows the scope used for the discovery with the FLI MicroLine ML09000 mounted.
* Thank you to Leonid Elenin, Kelly Beatty and Sky and Telescope for permission to use this information.
MicroLine ML09000 used at prime focus for the discovery of Comet Elenin (C/2010 X1)