RASC Hamilton Comet C/2012 S1 (ISON) - putative dSLR Image

[David Galbraith]

Hi,

As I have reported, this morning I took several dSLR images of the morning sky in the area where Comet ISON should appear, from the Burlington Waterfront. I wasn't able to spot the comet with binoculars or a 5" Mak telescope.

Attached is an attempt to find the comet on one of the frames from the tripod-mounted dSLR, compared to predicted locations of the comet and some markers. On the right is the predicted location of the comet at 6:15 AM relative to Mercury, Saturn, and the star Zubenelgenubi, a Stellarium screen capture from yesterday, for 6:15 AM this morning, with the comet highlighted.

On the left is an inverted B&W image from this morning, cropped, with contrast and brightness adjusted. This was a 4 second exposure at ISO 800, f/4.7, 63 mm focal length lens. There is a faint smudge in the correct spot. The enlarged rectangle above the labelled point on the larger image to the left is a 2x enlargement relative to the original pixels of the image.

The smudge is very close to where the comet should be. The ratios of distances on the photo between Saturn, Zubenelgenubi, and the putative cometary smudge are within 2% of those on the Stellarium screen capture.

A more sophisticated photographic and analysis approach would, I am sure, have done a better job (such as having the camera on a tracking mount and subsequently stacking several images) but given that there was perhaps 5 minutes without cloud of some sort before the area was just too light to find anything, I'm reasonably sure that the smudge represents the comet. I'd be happy for feedback.

cheers,

- David 		 	   		  
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