A spectacular set of photos taken by an amateur astrophotographer chronicles the evolution of Comet ISON over the last few months, which has seen the much-hyped icy wanderer brighten so much that it's now visible to the naked eye.
"In September, ISON was just a smudge smaller than most stars,"Mike Hankey wrote SPACE.com in an email. "The tail, while visible, was short, faint and had little detail."
Hankey started imaging Comet ISON using a 14.5-inch RCOS telescope located at the Sierra Remote Observatories in Auberry, Calif. He spent roughly an hour each morning imaging the comet remotely from the California observatory while he was at home in Maryland. [Photos of Comet ISON: A Potentially Great Comet]
'As the weeks went on, the comet grew brighter and larger.'
- Photographer Mike Hankey
"I experimented with various exposure lengths, tracking settings and processing techniques. As the weeks went on, the comet grew brighter and larger," Hankey said.
Comet ISON is barreling toward a close encounter with the sun on Nov. 28, when the object will skim just 730,000 miles above the solar surface. If ISON survives this close pass, it could put on a great show for skywatchers throughout much of December, experts say.
But the celestial fireworks have already begun.
By mid-October, ISON had grown in size significantly, taking up a respectable portion of the photographer’s CCD chip. Before long, the comet with its tail would not fit in the available field of view. After another two weeks, ISON grew so much that Hankey could no longer fit the comet on his imaging CCD without cropping out some of the tail.
"The real excitement started, though, on the morning of November 10. As soon as the first image was downloaded from the camera and displayed, I saw a distinct jet shooting out of the coma that I had not seen previously," Hankey said.
The photographer managed to capture startling detail of the increasingly bright ISON on Nov. 14, when the comet entered full outburst mode.
"It was brighter than I had ever seen and had an amazing detail; multiple jets radiating from the coma were evident," Hankey said. Prior to Nov. 14, Hankey had been shooting 180-second exposures, but due to the decreasing window of time he shortened this to 60 seconds.
To see more amazing night sky photos submitted by SPACE.com readers, visit our astrophotography archive.
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