A Comet Caught by Its Trail
Comet trails have been imaged before — but with very big scopes. To mention a few examples I've found: the orbiting Infrared Space Observatory recorded the trail of periodic comet 2P/Encke in July 1997; Steward Observatory's 2.3-meter Bok Telescope imaged it in September 2002; and NASA's Spitzer Space Telescope also photographed Encke riding its dust trail in July 2004.
At this point I knew that I would need some help. So I contacted a few people who'd assisted me before in explaining features in comet images I'd taken in the past. To my surprise, that same day a reply arrived that suggested my curious feature was the comet's trail. William T. Reach of Caltech's Infrared Processing and Analysis Center had logged many hours with Spitzer data. A colleague had pointed him to my image, and he kindly offered to make the dynamical calculations needed to determine the nature of the feature I'd imaged.
Two days later Reach had completed his simulations. "The structures were due almost exclusively to particles millimeter size and larger,” he reported to me, “and not the result of the dust tail created as a comet comes closer to the Sun." He noted that although I hadn't broken new scientific ground, he was particularly interested because of the small telescope I'd used. "This means that there is promise for doing more of this type of observation using small telescopes," Reach continued, because it's the kind of work that isn't done very often by professional astronomers using larger instruments.
This was just exciting for me. I have in the past contributed amateur observations to NASA's Deep Impact mission, and I've posted hundreds of images just for fun. But this was a "first" for me — no doubt looking for trails will become another one of my obsessions when I image comets in the future.