When I "retired" from systematic visual comet observing at the end of 2024 I did so with the caveat that I might occasionally "come out of retirement" for bright and/or interesting comets, and accordingly I expected to add additional comets to my tally from time to time. I never really thought, however, that I would completely fill up a ten-entry page and start a second such page in less than a year, but with the flurry of "bright and/or interesting" comets that appeared during the latter months of 2025, here I am . . .

This particular comet is an intrinsically faint short-period object that I have seen on three previous returns, beginning with its discovery return in 2003 (no. 335) and then in early 2009 (no. 446) as a part of "Countdown" and more recently in 2020 (no. 677). In my write-ups for both the 2008-09 and 2020 returns I noted that the return this year would be a relatively favorable one, and in due course the comet was recovered on July 20, 2025 by the Pan-STARRS survey in Hawaii, about three weeks before it went through opposition. It remained primarily within southern hemisphere skies afterwards and was imaged on a fairly regular basis, and I successfully imaged it a couple of times (in mid-September and early October) via the Las Cumbres Observatory network when it was still a relatively faint object near 18th magnitude. It apparently began to brighten somewhat rapidly after that, and when the final images were obtained by observers in the southern hemisphere at the beginning of November before it entered evening twilight, it was near 12th to 13th magnitude.

Comet Christensen was nearest Earth (0.43 AU) on November 9 and went through inferior conjunction with the sun about a week later, and by the last few days of November began emerging into the northern hemisphere's morning sky. The earliest post-perihelion images I'm aware of were taken on the 26th, when its elongation was 26 degrees, and showed it as being between magnitudes 9 1/2 and 10. The comet's elongation has been steadily increasing since then, but in all honesty in my current state of "retirement" I wasn't sure I would bother looking for it. However, on the morning of December 2, when I was already up to obtain one final observation of Comet 3I/ATLAS (no. 769) -- now having faded slightly, to a bit below 10th magnitude -- before the full moon, I decided I would go ahead and try for it (with its elongation having by then increased to 34 degrees), and after it had emerged from behind the trees I have in that direction I successfully detected it near the beginning of twilight as a small and moderately condensed object near magnitude 10 1/2.

Comet Christensen is presently located in southeastern Virgo 2 1/2 degrees east of the star Kappa Virginis and is traveling towards the northeast at slightly over 20 arcminutes per day, gradually curving more directly eastward. As it continues pulling away from both the sun and Earth its elongation hereafter increases more slowly, to only 44 degrees by mid-December and to 54 degrees by the end of the year; meanwhile it will likely fade quite rapidly. With all this, and with the bright moon now in the morning sky, it is rather unlikely that I will look for it again. But, to address the thoughts that I expressed at the end of my write-up for its 2020 return, I was indeed able to grab at least one observation of this comet this time around . . . and, for whatever it's worth, this turns out to be the brightest observation I have ever made of it.

INITIAL OBSERVATION: 2025 December 2.52 UT, m1 = 10.4, 1.4' coma, DC = 4-5 (41 cm reflector, 70x)

772. COMET P/(139359) P/2001 ME1          Perihelion: 2001 August 12.36, q = 0.357 AU

Once again, I add a comet to my tally retroactively, an object I briefly observed as an "asteroid" on a single night almost a quarter-century ago. It was discovered on June 16, 2001 by the LINEAR program in New Mexico, already a somewhat bright object near 14th magnitude. I happened to be in Zimbabwe at that time, in order to observe the total solar eclipse that took place on June 21, but after my return a few days later I tried to make plans to observe it. The evening of the 25th started out cloudy, but towards midnight I saw that the sky had cleared somewhat, and despite the fact that its altitude was starting to get somewhat low and the conditions still weren't ideal, I managed to spot 2001 ME1 as a stellar object near magnitude 14 1/2 (although given the conditions I considered this somewhat uncertain and suspected that it might have been slightly brighter than that). I was only able to follow it for about eight minutes before clouds moved in again, but during that time I detected clear motion (as it was then traveling at over seven degrees per day).

At the time of my observation 2001 ME1 was located 0.110 AU from Earth, and it passed 0.097 AU from Earth on the 29th (which, incidentally, puts it in 13th place on the list of closest-approaching comets on my tally). It rapidly moved inside Earth's orbit and accordingly faded quickly, and this, combined with its rapidly-shrinking elongation as well as increasing moonlight in the evening sky kept me from attempting to observe it again. The final ground-based observations before it disappeared into sunlight were obtained on July 4, and it was later picked up as a faint object in mid-January 2002. After observations were obtained around the time of its subsequent perihelion passage in December 2005 it was assigned the permanent number (139359) in December 2006.

(139359) 2001 ME1 travels in an orbit with a period of 4.3 years and an eccentricity of 0.87, which can be considered "cometary." The cometary nature of its orbit was evident at the time of its discovery announcement, and even in my observing notes for my observation I put the word "asteroid" in quotation marks, in anticipation of the possibility that it might actually be found to be a comet at some point. For the next couple of decades it was never observed as cometary, however just over a year ago it was identified as a member of a recently-christened class of objects called "dark comets," i.e., apparent "asteroids" that exhibit non-gravitational forces indicative of a cometary nature but not exhibiting cometary activity. In my statistical analysis that I completed after my "retirement" from systematic visual observing at the end of 2024 I specifically mentioned it in this context as a reasonable candidate for a retroactive addition to my tally someday.

In a just-published paper written by Qicheng Zhang at Lowell Observatory and his colleagues, the authors identified (139359) 2001 ME1 with a comet that was discovered by Thai researcher Worachate Boonplod in images taken by the LASCO C2 and C3 coronagraphs aboard SOHO shortly after mid-November 2018. The authors then were able to identify it in images taken with one of the Heliospheric Imager instruments aboard the STEREO-A spacecraft, and in ground-based images taken in early December 2018 by the Zwicky Transient Facility (ZTF) survey in California, where it initially appeared marginally cometary. They have also identified it in STEREO-A images taken in July and August 2014 and it also appeared marginally diffuse in ZTF images taken in March 2023. At the time of the LASCO and STEREO observations in 2018 it appeared at a very high phase angle (peaking at 176 degrees) which accordingly produced strong forward scattering of sunlight and a distinct cometary appearance. The identification as a comet seems solid, although the data indicate a very low activity level (a small fraction of 1% of the activity level of a more typical cometary nucleus of a similar size). The orbit has apparently been relatively stable for several millennia and the repeated close passages to the sun have apparently all but depleted its supply of volatile materials.

Figure 2 from the paper by Zhang et al (2026). These are "stacked" images taken by the LASCO coronagraphs aboard SOHO and by one of the Heliospheric Imagers aboard the STEREO-A spacecraft, as well as two ground-based images taken during the course of the Zwicky Transient Facility (ZTF) survey.

Unfortunately, it does not appear that this newly-identified comet will be amenable to detailed observations anytime within the near-term future. Its next perihelion passage is in June 2027, although this takes place on the far side of the sun from Earth, and thus there will not be any forward scattering enhancement when it passes through the LASCO field of view; it may be observable from the ground a couple of months earlier when it should be near 18th or 19th magnitude. It makes somewhat close approaches to Earth in September 2031 (0.63 AU) and in February 2036 (0.44 AU); the earlier of these does take place near inferior conjunction (and a corresponding phase angle of 170 degrees) and thus there should be some forward scattering enhancement detectable by whatever coronagraphs might be operating then. There are some very close approaches to Earth later in the 21st Century -- 0.117 AU in February 2062 and 0.070 AU in June 2070 -- but, of course, any observations then will have to be made by future generations of observers. Curiously, the comet also passes close to other planets in the inner solar system, for example, both Venus (0.047 AU in June 2053 and 0.083 AU in September 2057) and Mercury (0.034 AU in August 2057 and 0.039 AU in December 2061) have close approaches, and the comet passes only 0.015 AU from the large main-belt asteroid (4) Vesta in February 2032.

OBSERVATION: 2001 June 26.23 UT, m1 = 14.4:, 0.0' coma, DC = 9 (41 cm reflector, 189x)

773. COMET MAPS C/2026 A1          Perihelion: 2026 April 4.60, q = 0.006 AU

The first "real-time" addition to my comet tally in 2026 comes at a time of deep emotional turmoil for me. A week and a half ago the government of this country launched an unprovoked, illegal, and unconstitutional war against the nation of Iran, which at this writing has already cost the lives of several American military members and, among other things, resulted in the killing of over 100 school children at an Elementary School in southern Iran. The national and global political and economic effects of this war are only now beginning to unfold, and who knows what else will happen in the days and weeks to come . . . As any long-time readers of this web site should know, a quarter-century ago I made two "scientific diplomacy" visits to Iran (in 1999 and in 2000), events that I consider among the top highlights of my life, and found the Iranian people to be among the warmest and friendliest people I have ever encountered. I continue to remain friends with some of the people I met during those trips, and I have tried reaching out to them during the recent events, but thus far I have not heard back. I can only hope that they are OK, and that somehow, some way, this current travesty can end sometime soon without too much damage being wreaked, in Iran, here in the U.S., and the world at large. In the meantime, though, I am filled with shame and disgust at these atrocities that are being committed in my name.

Getting back to comets . . .

The comet in question here turns out to be a most interesting one. It was discovered on January 13, 2026 by a quartet of four French amateur astronomers -- Alain Maury, Georges Attard, Daniel Parrott, and Florian Signoret -- utilizing a remotely-controlled telescope in Chile. (The name "MAPS" is an acronym comprising the first letters of the last names of the four discoverers.) The MAPS team has discovered a handful of earlier comets, and for a few years back in the 1980s Alain Maury worked with the Second Palomar Sky Survey and had a couple of comet discoveries to his credit during that time (neither of which I observed); I met him at a couple of conferences during that general time frame. Daniel Parrott is the author of the Tycho Tracker software that is widely used by observers of small solar system objects.

Comet MAPS is a Kreutz sungrazer, the best-known and most studied of all the comet "families," and which has produced some of the brightest comets in all of recorded history. It is the third Kreutz sungrazer to be discovered from the ground during the past 15 years: the first was Comet Lovejoy C/2011 W3, which was briefly a "Great Comet" for the southern hemisphere after it passed through perihelion in mid-December 2011, although the nucleus itself apparently disintegrated as it did so, and the other was Comet ATLAS C/2024 S1, which disintegrated during its approach to perihelion, as documented by the LASCO coronagraphs aboard SOHO. I was able to grab a few observations of Comet Lovejoy as a "ghostly" object after it came back north in late January 2012 (no. 500) but, in significant part due to the hospitalization I underwent in the early autumn of 2024, I never had a chance to look for Comet ATLAS, although I was able to image it on a couple of occasions (while confined to my hospital bed) via the Las Cumbres Observatory network; I discuss this, and show one of those images, in a previous entry.

Comet MAPS was about 18th magnitude, and already exhibiting a distinct tail, at the time of its discovery. I obtained my first LCO images as early as January 14 -- the information from which was included on the comet's discovery announcement -- and have been imaging it on a fairly regular basis since then. It has brightened rather rapidly since its discovery, and the images I've taken, as well as those taken by other observers, have shown the development of a rather significant gas coma, although thus far there hasn't been much in the way of significant dust development. Within the recent past it had brightened to the point that I felt that visual observation attempts might be worthwhile, and on the evening of March 5 -- the first night with significant dark time after the recent full moon -- I successfully detected it. Despite being located only a few arcminutes from a 6th-magnitude star (HD 16825) I could see it without difficulty as a diffuse, vague, and slightly amorphous 12th-magnitude object.

  Las Cumbres Observatory images I have taken of Comet MAPS. LEFT: January 14, 2026 (slightly less than two days after the comet's discovery), via the LCO facility at the South African Astronomical Observatory. This is a "stack" of three 3-minute exposures. RIGHT: March 10, 2026 (a little over four days after my first visual observation), via the LCO facility at Siding Spring Observatory in New South Wales. This is a single 3-minute exposure.

At the time of that observation Comet MAPS was located in far eastern Cetus and traveling towards the northwest at approximately 45 arcminutes per day. Over the next few weeks it gradually accelerates and curves more directly westward, and in about two weeks or so it begins disappearing into evening twilight. Recent reports I've read and images I've seen -- including a set I took on the 10th -- suggest it has continued to brighten, and I am cautiously optimistic of observing it another one or two times before it slips into the dusk.

As for what happens when and after Comet MAPS passes through perihelion on April 4 . . . We've essentially been in uncharted territory since its discovery, since no Kreutz sungrazer has ever been discovered this far in advance of perihelion. (Indeed, pre-discovery images of the comet taken as far back as December 18, 2025 by the ATLAS program's telescope in South Africa have since been identified.) At this writing it is already quite a bit brighter than Comet Lovejoy was at a similar point (and much brighter than Comet ATLAS was at its similar point), although it is also about four magnitudes fainter than the great Comet Ikeya-Seki 1965f was at its similar point. (That comet was easily visible with the naked eye during daytime, near magnitude -10, when it passed through perihelion.)

Taking all this at face value, it appears at least somewhat probable that Comet MAPS will survive its perihelion passage, although it may well fragment into several pieces as several previous sungrazers have been known to have done. A couple of hours before perihelion it passes directly behind the sun as seen from Earth, and then a couple of hours after perihelion it passes directly in front of the sun. After that it recedes from the sun, although it remains within a few degrees of the sun for several hours. We should certainly see a good show in the LASCO coronagraphs, and if it is bright enough -- which is at least conceivable, especially since there should be some brightness enhancement due to forward scattering of sunlight, provided there is a significant dust content -- it could theoretically be detectable during daylight. (This will occur during the late afternoon of the 4th from here in New Mexico, when the comet will be three degrees from the sun.)

In the days after April 4 Comet MAPS returns to the evening sky, quite possibly rather bright and with a significantly long and bright dust tail (like previous sungrazers have exhibited). The overall sungrazer trajectory favors the southern hemisphere, but those of us north of the Equator should still be able to see it, although it will remain fairly low in the southwestern sky. It will likely fade quite rapidly, and since it recedes towards the far side of the sun away from Earth, the elongation remains rather small, reaching a maximum of slightly over 36 degrees just after the beginning of May. By that time it will be all but inaccessible from the northern hemisphere, and will likely have faded so much that there may not be much of anything left to see.

Most Kreutz sungrazers have computed orbital periods in the range of a few centuries, but Comet MAPS appears to have a somewhat longer period, in the range of 1700 to 1800 years. In a recent analysis comet scientist Zdenek Sekanina suggests that it may be a fragment of one of several bright comets that appeared in A.D. 363, and thus may be a second-generation fragment of the original sungrazer parent comet, which is widely suspected as being a brilliant comet observed by the Greek scientist Aristotle in 371 B.C.

In any event, it appears at least theoretically possible that we may be seeing a rather bright comet, conceivably even a "Great Comet," in about four weeks' time, although it is also quite possible that Comet MAPS might disintegrate and we won't see much of anything. Considering the current rather dark state of world affairs, it might be good for there to be a bright comet for the people of the world to see, and perhaps begin to grasp our place in the universe and our common humanity. One can always hope . . .

INITIAL OBSERVATION: 2026 March 6.09 UT, m1 = 11.9, 1.2' coma, DC = 1-2 (41 cm reflector, 70x)

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