Wednesday, January 21, 2015

Capturing a Ghostly Visitor!

While the mainstream press has (thankfully) ignored it, amateur astronomer circles are buzzing with the "bright" comet C/2014 Q2 Lovejoy, delivering spectacular views even before Christmas. Discovered just a few months ago (August 17th, 2014) by Australian amateur Terry Lovejoy, imaging with a wide-field 8" telescope, it passed both closest to the earth and the sun a week or two ago, easily visible (about 4th magnitude) to the naked eye from a dark sky. I say the press thankfully ignored it because it is virtually impossible to observe from any urban area without a good knowledge of the sky and your equipment, and astronomy would be poorly served by the general public not being able to find a dim if not invisible glowing green spot from town.

Of course, while it was nearest to us, I was an inpatient at our local hospital.  Once out, the wife and warden, Melinda wouldn't consider my going out to darker skies.  They had a point - I was recovering from a cute bronchitis (acute - get it?) and exposure to cold night air might not be good for my recovery. Even setting up a small scope in the back yard Sunday night didn't scratch the itch enough, so on Monday the 19th (20th Universal Time), with moon waxing through the week and a weather forecast that also looked bleak, I talked Melinda into letting me go out for a few hours.

I took a very portable setup, my Polarie mount (made by Vixen), and planned to shoot wide angle with the DSLR camera. I needed a dark sky overhead with short driving distance, so went east on I-10, then south on Route 83 about 12 miles to some roadside tables. It was about a 45 minute drive, and should provide nice skies. I arrived after dark, did the quick setup include polar alignment, and was just about to do my first test shot and looked up - clouds! Fortunately they were thin, so I was able to do my pointing and framing of the field. With an 85mm lens, I could nicely get the comet along with the Pleiades in the same field. I should have used my Canon 70-200 zoom, but chose the decades-old Nikon glass because of its smaller size, and got some reddish star glow as a result, but otherwise think the result is good. Shown here is a 5-frame stack of 3 minutes each, ISO 800 and F/2.8. The comet was moving slowly enough that its trailing against the stars wasn't too objectionable for the 15 minutes.

The comet was visible to the naked eye as a greenish, not quite point-like star. It wasn't blinding, but was comparable to a 4th magnitude star nearby. In binoculars it was quite impressive! I used a pair of 9X63s that had a 6 degree field of view. From comet to Pleiades was almost exactly 2 fields of view, and the tail was visible in the binoculars reaching about 3/4 of the way to the halfway star.  The binoculars also amplified the greenish glow of the comet's coma, though no color could be seen in the tail.

EDIT:  Today, 29 January, I reworked the above images to use the camera raw files as starting point, rather than the original jpegs I used to quickly put up the post.  If you recall the original files, they suffered from some color gradients that looked a little garish on some monitors.  I think these are better.  The fisheye shots below are still from the original processing from jpegs...

I also decided to try a wide-field shot with the 16mm Nikon fisheye, also at F/2.8.  There is a huge confluence of objects large and small in this part of the sky, but as my time was running out, only got in 2 frames of 3 minutes each.  The stack is shown at left, with a labeled version at right.  Even with the Pleiades very near the zenith, the Zodiacal Light in the west nearly reached up to it!  Between the Zodiacal glow, and the Winter Milky Way glow, the nebulae in Orion, the Triangulum Galaxy hiding towards the right edge and a multitude of open clusters, it is a very nice wide field.

I quickly packed and left for home, getting there a little later than I had promised, but still before 9:30 pm.  Seeing the bright comet made up for any discomfort from the bronchitis, and while I'm still suffering some effects of it, can't say I'd be any better if I hadn't gone...

The next day I happened to be swapping e-mails with my observatory building contractor John Vermette.  He forwarded a copy of a photo he had taken at the same time I was shooting!  He uses more state-of-the-art equipment, a full-fledged CCD camera and a 4" telescope from his own back yard observatory near Foothills Mall.  This exposure with the monochrome detector (black and white) was 10 frames of 1 minute each, with 100 seconds each of color information through red, green and blue filters.  I think it is a spectacular image, particularly from town.  You owe it to yourself to poke around his website, and especially check out this frame in larger size.

Unfortunately, it is at its brightest now, and by the time the moon departs the sky in a couple weeks it will be fainter, though still perhaps naked eye.  I'll be taking a look - perhaps I'll see you somewhere under a dark sky!

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