Comet McNaught (C2006/P1) - Jan 8-20, 2007

This comet turned out to be much brighter than originally expected - brighter than Hale-Bopp, and the brightest comet since Ikeya-Seki in 1965. I admit it kind of took me by suprise. My first look at the comet came after I called Allen G and we agreed to meet out front of his home in the hills of Aptos with a clear view of the ocean horizon. The comet came into the evening sky on Jan. 8 and promised a few nights setting late enough in twilight that it would be visible and photograph-able. I spotted it in the 10x70 binoculars soon after sunset, guessing it's magnitude to be -1.5 by comparing to Venus. The tail was immediately visible as a bright, short fan shape. Allen set up his Televue scope and had an adapter to mate his shirt-pocket Nikon digital, and got some nice images. We were very lucky to have perfect weather - clean skies, warm, high pressure, and no wind. And not a cloud in the sky.

Jan 8 - At Allen Ginzburg's Home

My best photo of this night; Dimage A2. Photoshop CS2: levels, cropped.

Allen's picture; I post-processed in Photoshop CS2 by rotating the comet to proper orientation, and doing 2 passes using Astro Tools 'space noise reduction', and applying levels


Allen's picture; No post-processing, just size and .jpg'ing. Comet is setting over the trees at Schwann's Lagoon in Live Oak. has posted this frame. Nice work!

Chris Kitting snapped this nice shot of aerial travellers going their separate ways on this same night, from his backyard in the Hayward Hills. Nikon 80-400mm zoom on tripod.

Jan 9 - Off Western Drive

More perfect weather tonight. This night I drove up Western Drive on the extreme west side of town and found a spot with a perfect horizon, with the sun setting over a ridge a half mile away with some photogenic trees to frame the images. A nice added suprise was to find UCSC astronomer Stephen Thorsett walking by with his young daughter, and they enjoyed the comet show with me. All pictures are through the Megrez 80mm f/6 APO refractor with the ST2000XCM at T=-20C and with the GM8 mount only approximately polar aligned, with no self-guiding. Not necessary - the exposure lengths are all 1 second or less! Altitudes below are unrefracted, using time and ECU software.

0.3 second exposure, single-shot color processed with DDP option in CCDOPS5, then in Photoshop CS2: levels, AstroTools 'space noise reduction', color balance. Comet altitude is 1° 05', and the sun is -7.5°.

0.6 second exposure, single-shot color processed with DDP option in CCDOPS5, then in Photoshop CS2: AstroTools 'space noise reduction', unsharp mask, color balance. In the heat of battle, this one was under-exposed. Note the image is all in the lowest of the 8-bit levels. Comet altitude is 0° 55', and the sun is -7.7°.

0.8 second exposure, single-shot color processed with RGB option in CCDOPS5, then Photoshop CS2: unsharp mask, color balance, brightness/contrast. Comet altitude is 0° 48', and the sun is -7.8°.

0.8 second exposure, single shot color processed with RGB option in CCDOPS5, then Photoshop CS2: levels, cropped, curves, brightness/contrast, AstroTools: 2x 'space noise reduction'. Comet altitude is 0° 40', and the sun is -8.0°.

At the laptop, in fading twilight

1 second exposure, single-shot color processed with DDP option in CCDOPS5, then in Photoshop CS2: smart sharpen, AstroTools 2x 'space noise reduction', levels, crop. Comet altitude is 0° 30', and the sun is -8.2°

Jan 10 - At Cabrillo College on Horticulture Hill

Jonathan Crockett and I met and did find the comet on this cloudy, cold, and windy evening. But, it only stayed above the clouds long enough to tempt us to scramble and set up our gear, only to have it disappear behind the advancing front. Got one nice hero shot, and that's it.

Jan 11 - At Cabrillo College on Horticulture Hill

This time, we were joined by Chris Angelos, and also a mother and young daughter who stayed after a nice sunset to see the comet. It been almost doubling its brightness every other night... I estimate magnitude -3 this night, and the brilliant nucleus and fan tail were visible easily as soon as the sun hit the horizon, even though the comet was only 7 degrees above the sun and very deep in twilight. In fact, I had a hard time photographing it because the twilight was so bright it saturated the CCD camera even at the smallest exposure times, until relatively late in the show. And even then, the brilliant nucleus and very brief window of opportunity, led to underexposure on the tail due to the inability of the camera to show a raw image properly scaled. Jonathan took shots through his Megrez with his digital camera and will hopefully send me his best. Below, all are with the Megrez 80mm APO refractor, ST2000XCM with chip T=-20C. All are dark subtracted and flatfielded. My choice was to bring out the tail as much as possible, and different single-shot color processing was required for each exposure. The colors were a big problem on the early shots. Perhaps because the detector spent a fair amount of time overexposed before beginning shooting. Bad columns are also evident. All exposures needed photoshop 'clone stamp' tooling to remove blooming on the nucleus' pixel column. A very bright comet in very bright twilight - extreme conditions.

5:34:00pm. Exposure 0.02sec. sRGB+gamma in CCDOPS5. The nucleus was so bright it bloomed over the 16 bit limit. The short exposure led to grainy sky background and poor color rendition. Comet altitude is 2 56', sun is -4 28'.


5:36:54pm. Exposure 0.02sec. Comet alt = 2 24', sun -5 01'. sRGB+gamma in CCDOPS5.

5:39:00pm. Exposure 0.10sec. Comet alt = 2 03'. sRGB color processing in CCDOPS. The color was just impossible to fix, so I made this into a more artsy picture.

5:40:22pm, exposure 0.10sec. DDP single-shot color in CCDOPS. Photoshop - Heavy color alterations and processing to bring out the comet tail. Couldn't get the colors to look realistic. But it's got a great moody look so who cares about realism?

5:41:33pm. Exposure 0.11sec. DDP color processed in CCDOPS5. Photoshop CS2: slight hue/saturation, sharpen edges

5:42:07pm. Ambient twilight now low enough to allow better color rendition. Comet altitude= 1 33'. Exposure 0.11sec. RGB color processed in CCDOPS5. Photoshop CS2: Levels, sharpen edges, AstroTools 'space noise reduction'.

After Comet-set, our happy crew, including a lucky local and her daughter, who came for the sunset and got a lot more.

The sunset was nice, suitable for making this over-the-top amp'ed up version in Photoshop.


Chris Kitting got this nice moody shot from the Hayward Hills - 5:46pm PST. Nikon D200. 400mm on tripod. 1/6 sec at f/6.3 ISO 400. Photoshop: curves, cropped. Clouds over the SF Bay and San Mateo.

January 12 - Off Western Drive

This night, the night before perihelion and expected to be our last, Jay joined me. Plan "A" was to meet at the west field house at UCSC, but after 45 minutes of trying, I could not find an unobstructed horizon in the critical direction, so we both retreated to Western Drive, this time to the little park at the end of the cul-de-sac and with a nice view to an adjacent ridge essentially at 0 degrees altitude. We quickly assembled the neighborhood, who enjoyed the view of the comet while Jay and I both gathered camcorder footage. Jay used a telephoto lens on the front of his Canon, and I used the built-in 20x optical zoom, mounting the camcorder on the approximately polar aligned GM8 mount.


Jan 13 - Perihelion Day!

Weather was once again perfectly clear and cold and had many reports of easy daylight visibility. I gave it a try from home, at 1pm from my carport I hid the sun behind the neighbor's trees and found the comet easily in binoculars, and then by just looking up without the bino's. Amazing! My first daylight comet. I recalled my attempts to see Comet Ikeya-Seki in 1965 by hiding the sun behind a corner of the gym at Newton Junior High School, and failing. I estimated the magnitude at m=-5.5, definitely much brighter than Venus. It is not possible to get a good magnitude estimate after sunet, as Venus is too high and to much in a dark sky, while the comet was buried in bright twilight and only a couple of degrees up. Only by trying to remember what Venus looked like a month ago when it was setting in similar conditions in the west, could some guess be made. I thought about driving up to Berkeley to photo the comet setting over the Golden Gate Bridge - something I've wanted to do for some time. But I also wanted to attend the Santa Cruz Track Club annual banquet - so I compromised - I drove up to Fremont Peak hoping the gain in altitude would help make the twilight comet easier to see now that it was setting sooner, and I calculated it would set over Pacific Grove/Monterey Peninsula, making a nice shot. When I arrived, I found the campground gate locked - doh!! I needed to be there to see the comet set on an ocean horizon. Best alternative was to park in the upper lot and forget about using the telescope, and instead walk to the radio towers and photograph just using the dimage A2. I noticed a couple who hiked to the summit and stayed after sunset to see the comet with binoculars. It was a little less impressive than the previous night due to the early setting and a layer of haze near the horizon. But I snapped a few shots (posted soon).

Daylight Comet! 1:05pm. Dimage A2, overexposed, then severely 'level'ed in Photoshop CS2. The comet is on the left side of the bloom, just above a protruding patch of avacado tree leaves. The tail is pointing up and to the left.


Jan 14 - from home. No photos today, but I did find the comet in binoculars once again. But it was distinctly fainter. I'd estimate m=-4. I tried but failed to find it by naked eye. The tail was now less linear and instead came from the head in a wide near-circumference. The following day, Jan 15, I was not able to find it in binoculars. However, the sky was a bit hazier as well, and the comet was now south of the sun which made hiding the sun harder to do well.

Jan 19 - Coast Rd. I thought the show was over... but the jets of dust evaporated off near perihelion shot northward in a giant splash and graced the evening skies for several days this week. I missed the opportunity on the 18th but got a nice set of cloud silhouettes from the turnoff of Hwy 1 and Coast Rd a few miles north of Santa Cruz.

6:47pm. 44sec with ST2000XCM + 24mm Zuiko lens at f/2.8, on tripod. Venus is setting into the Pacific, and the comet streamers had to compete with a strong zodiacal light background. Visible to the naked eye even through the clouds. These streamers extend over 20 degrees above the horizon, and the head of the comet was over 21 degrees BELOW the horizon. Tip to tail, this comet is almost as big now as Comet Hyakutake. It's simply gorgeous! Dark subtracted and flat fielded, single-shot color RGB processed in CCDOPS. Photoshop CS2: levels, AstroTools 'make stars smaller', 'space noise reduction', 'deep space noise reduction'.


Jan 20 - Bonny Doon Airfield. I got together with the Santa Cruz Astronomy Club's monthly observing session, with my main goal to photograph the comet tail with tall redwoods in the distance as a foreground, and hopefully some deep sky targeting afterwards. The nucleus was now way deep into the southern hemisphere in microscopium, and yet the tail streamers extend across Aquarius and almost into Pegasus. Stem to stearn, the visible comet now extends almost 60 degrees by my estimate, and growing exponentially each day. This dramatic increase in side is because the comet was approaching us towards perihelion, which came on the near side of the sun, and the fantastic boil-off is headed into our direction. Interesting exercise - try and match up the star patterns last night to tonight. Not easy, because your expectation is that the tail is moving roughly like a planet, migrating slowly eastward. In fact, the tail has moved almost one entire wide-angle field of view upward in a single day! The treeline horizon in tonight's picture is approximately the top of the previous night's frame. The pair of bright stars in the Jan 19 photo at extreme upper left corner, are down almost at the treeline (one star has the hooked streamer going through it) in the picture at lower right. At this rate, the tail streamers will easly outpace the eastward moving sun and will stay in our sky for good - except that the waxing moon will ruin the view from now on. I also did some deep sky object photography after the comet show was over - here's a link to that page.


6:59pm. 1 minute guided. sRGB single shot color processed in CCDOPS5. Photoshop CS2: levels, color balance, rotate canvas, cosmetics on undersampled stars, AstroTools 'space noise reduction'. Horizontal light cirrus contrast with the blue dusty comet tail streamers. 4% cresent moon 3 degrees up, behind those trees, and lightened the sky significantly

7:04pm. 3 minute guided. sRGB single shot color processed in CCDOPS5. Photoshop CS2: color balance, rotate canvas, cosmetics on undersampled stars, levels, AstroTools 'space noise reduction', rebalance color, brightness, conrast, hue, saturation. 4% cresent moon 2 degrees up, behind trees.

7:25pm, just after moonset. 44 sec unguided on tripod. sRGB single shot color in CCDOPS5. Photoshop CS2: color balance, levels, AstroTools 'space noise reduction', more color balance, brightness, contrast