SOHO/Near-Sun Comet News and Views
2007 News

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December 22, 2007
Congratulations to Rainer Kracht on becoming the first to find 200 SOHO comets. A faint Marsden comet he reported yesterday was his 200th. This was the first Marsden comet since March 2006 and the 31st overall (according to the list on the Sungrazer Web site, although some may be reappearances of previously reported objects, as Marsden comets are believed to be periodic, with periods of about 5.5 years). As for the other low-inclination new comet group, this one discovered by Rainer himself, there hasn't been a new Kracht comet in the past two years. Rainer has proposed that as many as 7 Kracht comets seen in 2002 may return over the next 6 months, between February and July 2008, though some may be too faint to be seen in LASCO images.

Today, Arkadiusz Kubczak reported a moderately bright C3 Kreutz. Arek's comet, which approaches the Sun on a trajectory slightly to the left, or clockwise,of most Kreutz comets at this time of year, is probably Kreutz Subgroup II, akin to the Great Comet of 1882 and 1965's Ikeya-Seki. On December 20, Shihong Yuan reported a C2 Kreutz in yesterday's (UT) images. It was well seen, fairly spherical and condensed. Hua Su also reported a C2 Kreutz, this one on December 16.

December 14, 2007
The bright Kreutz (SOHO-1414) that I reported on December 12 as it entered C3 has completed its inbound journey, and was vaporized by its close approach to the Sun.. As it moved through C3 it brightened and developed a narrow and delicate tail that extended about a degree. It was well seen in C2, and visible (barely) up to the edge of the occcultiing disk. Although one of the brightest comets of the year, it didn't quite rival some of SOHO's most spectacular.

Yesterday, Rob Matson reported a Kreutz, faint in C3 and brighter in C2. When SOHO-1414 entered C3, it was trailed by a small, elongated companion, which was first reported by Parrish Collison, his first SOHO discovery after two years of  searching. I noted that the object appeared to be double, with two distinct components very close together. When SOHO-1414 was about halfway across the C2 field of view, I noticed on the opposite side of C2 (the field's upper right) what appeared to be a Meyer comet, and sure enough, it was confirmed as such. It should be the 83rd Meyer comet, which would put Meyer-100 about 2 years away.

December 13, 2007
Among the confirmations by Karl Battams yesterday were several milestones--among them SOHO's 1,400th comet (found by Bo Zhou); Zhangwei Jin's first SOHO comet and Michal Kusiak's first two; Hua Su's 150th and my 100th . Rainer Kracht is just one comet away from becoming the first SOHO hunter to find 200.

I found my 100th SOHO comet on December 10, after 6 1/2 years of hunting. (I started my search in late June of 2001. It took me 7 months to find my first SOHO comet, and 2 1/2 years to find my first 10.)  I sort of figured that after finding my 100th I would go into "semi-retirement" and look much less frequently. I probably still will do so, but I still had one surprise in store for me. The night after finding  no. 100, I got home late, and  noticed what might have been a comet entering the C3 field. I reported it, and sure enough, it's a very bright Kreutz comet that's now approaching the Sun. Shortly after that, I reported a much fainter C3 Kreutz, which Rob Matson posted 12 seconds before me, and we share credit for that one. It took me 5 months of searching to find comets 97-99; I found my most recent 3 in just over a day. Go figure.

December 10, 2007
It's been a busy time for SOHO hunting, now that the keyhole period is over. When Karl does the next round of confirmations, I should have at least one SOHO hunting milestone to announce. (Hint: check out my "My Search for SOHO Comets" page.)

Along with the usual Kreutz comets found in a comet storm period such as we're in, there have been a couple of other interesting finds. On December 3, Masanori Uchina reported a  non-Kreutz comet that entered the C2 field from the right of the Sun and cut across the upper right corner of the field, fading out when it was above the Sun. Today, Hua Su reported a Meyer comet in C2, the 82nd Meyer comet to be found. (On November 9, Zhangwei Jin detected a faint Meyer comet; it was Zhangwei's first SOHO comet.)

Don't forget to look up! Even as Comet Holmes fades, it's still visible from here in NYC (though no longer a naked-eye object), and is huge and magnificent from a dark-sky site. I'll soon be adding a page with my observations and photos of 17P/Holmes. Comet 8P/Tuttle, which I observed for the first time on December 1, is brightening as it heads towards a close approach to Earth in less than a month.

November 2, 2007
I'm sorry it's been so long since I last updated these pages. I've made all the comet totals current. Of course, the big cometary news is the enormous outburst of Comet 17P/Holmes, which on and just prior to October 24 increased in brightness within a matter of days (if not hours) by nearly a millionfold  to become an easy naked-eye object in Perseus--it's been holding steady for the past week at about magnitude 2.2, and has emitted two expanding, concentric shells, the outer of gas and the inner of dust.

The big SOHO comet news in recent months was the return of SOHO's first official periodic comet, P/2007 R5, on September 10-11. The return of this comet, which is closely related to SOHO another comet (C/2002 R5), had been predicted by Sebastian F. Hönig. The comet was found by Bo Zhou, and it reached perihelion within about 4 hours of the predicted time! It had previously reached perihelion on September 5, 1999 and September 8, 2003, and had been found on those returns by Terry Lovejoy and Kazimieras Cernis, respectively.

July 17, 2007
Today Karl Battams posted confirmations of SOHO comets from June and July. They bring the SOHO comet total to 1343. All were Kreutz, except for a non-group comet found by Hua Su on June 25. Bo Zhou found 15 of the comets, Karl Battams and Hua Su, 3 each, I found 2, and Alan Watson, Rob Matson, Arkadiusz Kubczak, and Shihong Yuan, 1 each. All of the Kreutz comets over the past 3 weeks have been found in C3.

July 4, 2007
Yesterday, Karl Battams confirmed 14 comets found between May 16 and May 30, with June confirmations yet to come. One was a Meyer comet found by Hua Su; the rest were Kreutz. Seven of these were discovered or co-discovered by Bo Zhou, three by me, two by Rainer Kracht, and one by Maik Meyer.

A C3 comet first reported by Hua Su is approaching the Sun now. The C2 comet storm period is likely over; nearly all of the Kreutz comets found between now and early to mid-October will be discovered in C3 images.

June 15, 2007
It has been a very busy few weeks. As this "comet storm" period persists, nearly a Kreutz fragment per day has been found in C2 images. Many of them, particularly in the past 10 days, have also been visible in C3. These include an especially brilliant Kreutz comet found by Shihong Yuan on June 6, which although relatively faint through most of its passage through C3, developed dramatically as it approached the Sun, growing a substantial tail that appeared to lengthen even as it passed through C2, becoming more than a degree long. What's more, it persisted more than 12 hours after the comet's head passed behind the occulting disk, presumably until well after the head had vaporized and the comet had passed perihelion.

May 21, 2007

A few days ago, Karl Battams posted confirmations of 23 comets, including 16(!) found by Bo Zhou, including 11 realtime comets found between April 18 and May 15 as well as 5 archive claims. Confirmations also included a C3/C2 Kreutz found by Shihong Yuan and several previously mentioned comets: a bright Meyer comet plus a Kreutz found by Rainer Kracht, Vladimir Bezugly's Kreutz of April 22, and three C2 Kreutz that I discovered.

Since the confirmations, Bo Zhou has continued his amazing pace of discovery, finding 5 more Kreutz comets. I found a C2 Kreutz today in delayed images, and Hua Su reported a rather bright Meyer comet on May 18. It was visible in both C2 and C3.

Meanwhile, on the STEREO front, Alan Watson and others continue to detect various known asteroids down to fainter than magnitude 13, and known comets such as 2P/Encke and 29P/Schwassmann-Wachmann 2.

May 6, 2007

Less than a month after Comet 96P/Machholz put on a fine show in SOHO (and STEREO), another short-period comet passed through the outer part of LASCO C3. Comet 2P/Encke entered C3 on April 27 at lower left, below the pylon, and crossed the bottom of the field from left to right, showing a nice tail. Here is an image of Encke created by Rainer Kracht from STEREO data.

After a slow start, the C2 "comet storm" season that runs from April to June has picked up. No Kreutz comets were found between April 8 and April 20, when Rainer Kracht reported a C2 comet. Vladimir Bezugly found one two days later, and Bo Zhou found three more in the last week in April, plus another on May 3. Bo had one other C2 comet reporton April 18 that I suspect is a real comet but wasn't certain enough to confirm it. (Yesterday, Bo reported three possible members of the great Kracht comet "storm" of May 5-15, 2004, in which at least 9 Kracht fragments appeared--one of Bo's new ones has been confirmed so far.) Rainer Kracht reported a bright Meyer comet in C2 images of May 2; it was also visible in C3. On May 4, I found two Kreutz comets. both quite faint, within an hour of each other, one in C3 and one in C2. The C3 comet was later nicely seen in  C2, moderately bright and with a short tail. These were my SOHO comets #90 and 91.

April 8, 2007

Comet 96P/Machholz has completed its passage across the C3 field of view. This short-period comet, discovered by American amateur astronomer Donald Machholz in 1986, made its its second passage through the SOHO FOV. It entered C3 on April 1 near the bottom of the field, a bit below the pylon, then moved clockwise skirting the edge of  the field and finally exiting to the upper left. Comet 96P/Machholz is believed to be associated with the Marsden and Kracht comet groups as well as the June [daytime] Arietid meteor shower; the comet is likely their parent body.

On Friday, Karl Battams confirmed six SOHO comets, the six most recent I mention below (four by Bo Zhou, one by Vladimir Bezugly, and my Kreutz of March 29 (the only C2-only comet of the group). This brings the official SOHO count to 1279. Karl mentioned that most if not all of these comets were observed in the SECCHI HI-1A instrument as well, thanks to the hard work of people like Alan Watson and Rainer Kracht. This means, for one thing, that Karl will be able to measure positions for these comets both in LASCO and at least one STEREO instrument, doubtless improving orbital accuracy.

Two days ago, Bo Zhou reported a faint Kreutz comet entering C2. It's easily visible in 3 images, but there's a gap of an hour between images, and I haven't been able to make anything out clearly in the images to follow. Hopefully Karl will be able to fsee it in enough images to officially confirm it.  Last night I found a C2 Kreutz after a gap in images. It was moderately bright and visible in 8 or 9 images.

March 30, 2007

Bo Zhou  found two more nice comets in the past few days.. On March  27, he found a C3 Kreutz comet (likely Subgroup II)  traveling up along the lefthand edge of the occulting disk pylon. It was rather bright and teardrop-shaped in C2. The next day, he reported a rather bright C2 Meyer comet that was also visible in C3. Yesterday I reported a Kreutz comet entering C2, elongated and fairly diffuse.

March 23, 2007

Two days ago, Bo Zhou reported a Kreutz comet in C3. Although near the edge of the field, it brightened and showed a teardrop shape. It was fairly bright in C2 and looked very nice there as well, trailing a narrow, straight tail.

March 18, 2007

Terry Lovejoy of Australia, who in 1999 became the first amateur to discover a comet in online (SOHO) images, has achieved what appears to be another cometary first. His discovery of Comet 2007 E2 (Lovejoy) is apparently the first to have been made with a (non-CCD, no telescope) digital camera, a Canon 350D (Digital Rebel XT) DSLR. Terry joins three other SOHO comet hunters to have received discovery credit for comets they've found in the night sky. Kazimieras Cernis of Lithuania, finder of more than 20 SOHO comets, discovered three comets visually between 1980 and 1990. Sebastian Hönig, finder of 39 SOHO comets, discovered C/2002 O4 in a 10-inch SCT on July 22, 2002.(It was the first comet discovered by a German amateur since 1946.) Austria's Michael Jäger, who discovered P/1998 U3 photographically, also was the co-finder of C/2005 P3 (SWAN) in SOHO's SWAN images.

Comet Lovejoy was found at a declination of -50, and visible just to southern-hemisphere observers. By its first published orbit, the comet will reach perihelion next week at a distance of 1.09 a.u. from the Sun. By April 20, it will have passed north of the celestial equator, It will be closest to the Earth around April. 25, at around 0.44 a.u. away, when it  may be about magnitude 7.5. and visible in the morning sky.

It has been a slow time for SOHO comet hunting, with the last comets to be found a C3 Kreutz by Vladimir Bezugly on March 9, and another C3 Kreutz found by  Bo Zhou on March 2. SOHO is emerging from a keyhole period, but the C3 Kreutz track will soon be occulted by the pylon (of the occulting disk), so conditions are less than optimal for finding SOHO comet for the next few weeks--but still, we persist in trying.

February 25, 2007

It has been a slow time for SOHO comets for the past week, largely due to the keyhole period. (LASCO is now closed, as the SOHO spacecraft is being flipped.) On February 24, I found a C3 Kreutz comet, but due to the huge gaps in images, it may not be visible in enough positions to be made official. Earlier in the month, Karl Battams confirmed 11 SOHO comets, bringing the total to 1,269. These included Masanori Uchina's first, a bright one that was found near the edge of the C3 field. Bo Zhou and Hua Su also found bright C3 comets Bo Zhou's becoming especially bright. Hua Su also found a  C2 Meyer comet, as well as a C3 non-group comet. Since Karl's confirmations, Hua Su found two more C3 Kreutz comets and Arkadiusz Kubczak found one; Bo Zhou also found an archival Kracht comet from May 13, 2004, one of 7 Kracht fragments thatt appeared in a three-day span.

January 27, 2007

Yesterday, Karl Battams confirmed 10 comets, bringing SOHO's total to 1258. These include Alan Watson's first comet, a Meyer comet that I found on January 11, and two non-group comets with trajectories somewhat similar to Kreutz comets. One was found by Luciano Cane and one by Rainer Kracht; Rainer's comet had previously been classified as an X/comet.

Karl Battams has posted a link to an animation of Comet McNaught passing through STEREO, as well as still images of the comet in STEREO, to the SOHO Sungrazer site's news page. SOHO comet hunters Rainer Kracht, Rob Matson, and Alan Watson have all been working with STEREO images and identifying asteroids in them. STEREO images are currently available only in FITS format and require special processing.

January 15, 2007

Comet McNaught has finished its passage through the C3 field of view, and SOHO's image cadence and C3 resolution have returned to normal. A decrease in the "pixel bloom" as the comet was exiting C3 implies that the object is fading, and visual observations bear this out. Here's hoping that the comet puts on a fine show for our Southern Hemisphere friends.

January 13, 2007

Comet McNaught (C/2006 P1), the brightest comet ever seen in SOHO and the brightest to be observed since Ikeya-Seki in 1965, is currently making its way across the LASCO C3 field of view. It has become visible with the naked eye in full daylight, although it is very near the Sun. It's clouded out here in New York, but I was able to see the comet on four successive nights earlier in the week, a beautiful sight in binoculars despite clouds and horizon obstructions. I've put up a page on it.

The last few weeks of 2006 were a for SOHO comet hunting; an average of a comet a day was discovered during the last 3 weeks of the year. Karl Battams confirmed most of these in late December to bring SOHO's total to 1248. All except a Meyer comet found by Rainer Kracht were Kreutz comets, about half visible in C3 as well as C2. Among the more intteresting were a pair of relatively bright Kreutz comets, found by me and Bo Zhou, separated by about 8 hours, which in C3 emerged out of the Sagittarius star clouds; when they entered C2, three additional fragments were seen between them. The first SOHO comet of 2007 was found by Hua Su on January 5; since Karl's last confirmations, about half a dozen SOHO comets have been found, including the first comet found by Alan Watson of Melbourne, Australia, who had been monitoring LASCO since SOHO-1000 days, a Meyer comet that I found a few days ago, and a possible non-group comet found by Luciano Cane that followed a track similar to a Kreutz path except that it didn't seem to curve.

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