The discovery of new comet 6AC4721

The MAPS (Maury, Attard, Parrott, Signoret) program is an independent program to discover near-Earth asteroids using the synthetic tracking technique.

All the images in this pages are copyrighted, they can be used provided you cite MAPS as the origin (copyright MAPS 2026).

All four are amateur astronomers. Alain Maury worked as an engineer at several observatories (Côte d'Azur Observatory, Mount Palomar Observatory in California, La Silla Observatory, and the European Southern Observatory) before founding his own observatory in San Pedro de Atacama, Chile. The other three are amateur astronomers but professional computer scientists, which has allowed them to develop a high-performance software suite. Georges, Florian, and Alain are members of GAPRA (Groupement d'Astronomie Populaire de la Région d'Antibes - Popular Astronomy Group of the Antibes Region).

Daniel Parrott is the author of the Tycho Tracker software  and we collaborated extensively with us at the beginning, but in practice, he never participated in the observations.

The program began in 2020 and has since led to the discovery of 318 near-Earth asteroids and 7 comets. 8 now. This makes it the most effective European program, second only to the major NASA-funded search programs for this type of asteroids. For context, MAPS only operated for 9 months of the year (due to a technical failure) and discovered 102 near-Earth asteroids. In comparison, the European Space Agency's program discovered 3, another French amateur astronomer (Christophe Demeautis, PASTIS program) also discovered 3, another French amateur astronomer (Florent Losse) discovered 1, and two other French amateurs observing from Morocco (Claudine Rinner and Michel Ory) discovered another, while Georges Attard, using his personal telescope in France, also discovered 1. At the international level we discover more near-Earth asteroids each year than many professional programs, such as those of the Mount Palomar Observatory (ZTF), Ginop (Hungary), Altay (China), Purple Mountain (China), WFST (Chinese 2.5m telescope).

The program is funded by Alain Maury, but we received two grants from the Planetary Society which allowed us to purchase 4 new cameras which will soon be put into service.

Among the notable discoveries, asteroid 2023DW, which at the time of its discovery had a non-zero probability of impact with Earth, asteroid 2025OH, which is the near-Earth asteroid with the highest inclination (175 degrees on the plane of the ecliptic, that is to say, in fact, inclined at 5 degrees on the plane of the solar system, but rotating in the opposite direction to the planets).

We discovered 2023DW without giving much thought to what would happen next. A week after our discovery, NASA and ESA servers realized that this asteroid could collide with Earth in several years (with a very low probability though). At the time, it generated a bit of buzz, but we were rarely mentioned. The vast majority of web pages discussing this asteroid focused on NASA's discovery that it could collide with Earth. We had encountered similar issues with other discoveries made at the SPACE (San Pedro de Atacama Explorations) observatory, so for this new comet, we preferred to invest some time managing the communication a little bit (hence this page).

And so, our latest discovery is this new comet which could eventually become bright enough to perhaps be visible to the naked eye by April 2026.

Circumstances of the discovery 

The four telescopes operate completely automatically, thanks in particular to fairly complex scripts written using the Prism program . During the day, the control PCs for the telescopes and cameras are switched off. One of the image processing PCs "wakes up" the equipment when the sun is 5 degrees below the horizon. The dome opens, the cameras are cooled to -10 degrees Celsius, and when the sun is 15 degrees below the horizon (i.e., when the sky is truly dark), the PCs begin observing the sky, selecting fields according to several criteria: that the field has not yet been photographed in the last five days, avoiding the Milky Way (too many stars), and being far enough away from the moon if the moon is visible. The telescope mount is pointed at the selected area. The first camera takes a short image to check the telescope's position in the sky, recenters if necessary, finds the correct focus position to obtain sharp images (the focus changes depending on the temperature during the night), and takes a series of 36 30-second exposures. During each exposure, the small PC that controls each camera applies several preprocessing steps, divides the image by 2 (binning), recenters it relative to the first image in the series, and sends the result to one of the image processing PCs, which are quite powerful (i9 with 64GB of RAM and terabytes of hard drive space, equipped with an Nvidia RTX3090 GPU - Graphics Processing Unit).

Once these PCs have received the 36 images, a script launches the Tycho-Tracker program, which analyzes them and detects the asteroids present in the images. The four cameras take contiguous images, resulting in a field of view measuring 3.3 x 8.8 degrees (roughly 6.5 x 17 times the size of the moon in the sky). This software can recognize asteroids already known (those in the mpcorb.dat database), and software written by Georges and continued by Florian allows visualization of the movement of these asteroids, providing several characteristics of the object, including the probability that it is a near-Earth asteroid, and the quality of the detection—that is, whether the object has a high probability of being real, a good probability, or a low probability (high, medium, or low). All of this is done autonomously. 

The observers (Georges, Florian, and Alain) periodically check one of the GPU PCs to see what data has been discovered overnight. Currently (summer in Chile and winter in France), there is a four-hour time difference. Alain is a night owl (usually going to bed around 8:00 AM), while the French (Georges and Florian) wake up around 7:00 AM, which is 3:00 AM Chilean time.

On January 13th, the program was running as usual. Alain was conducting astronomical tours, and that evening he was showing the sky to a couple of American amateur astronomers who wanted a private tour. At the end of the tour, he went home and checked the GPU PC. There were two objects that Tycho had detected as "high unknown." The second was surrounded by a faint halo, distinguishing it from an asteroid. It was necessary to verify that it wasn't a known object, that it wasn't a distant artificial satellite (we frequently detect satellites such as the James Webb Telescope, Spektr, Glenn2, and a few others).

This is the discovery image; we see the object in the center, and we see that there is a "halo" around this object.

Alain wrote on our WhatsApp at 1:41 AM

-I believe that 4721 is a comet. 

At 2:30 am (6:30 am in France), Georges can't sleep, wants to go back to sleep, but hears his phone beeping.

- Wow, it's really diffuse, you're right.

Meanwhile, Alain sent the position measurements to the MPC (Minor Planet Center), and launched exposures on another telescope (a Celestron 14 Hyperstar) to confirm the discovery.

Florian also wakes up early, and since we haven't discovered anything interesting since the beginning of the year, he says at 7:11 am:

- Hi. A comet in the middle of a drought? Wow, I'm crossing the fingers of my hands and toes!!

When the C14 image comes out, there is indeed a blurry spot, typical of a distant comet. In the meantime, the MPC has placed our 6AC4721 on the MPC's NEOCP (Near Earth Object Confirmation Page). 

Why this temporary name?

The acquisition program automatically assigns a temporary name (it has to). Therefore, 6AC4721 is named that because:

• 6 because we are in 202_6_, the 6th is the last number of the year.
• A, in January, the first month of the year (in February B, March C, etc...)
• For programmers, it's easy to understand: the first days of the month are 1, 2, 3...9, then you use the letters of the alphabet, so A would be January 10th, and C the 12th. The comet was discovered on the morning of the 13th, but during the night of the 12th to the 13th, so C
• 4 because it was discovered with the 4th telescope 
• 7, because it was the 7th field observed that night.
• 2, because we do not use the images in real format (60 megapixels, images of 120 and some MB) but "binnont" (group 2x2) the images so that the calculation time is reduced.
• 1, because it's the only new object discovered in this field. In the very rare case where we find two new objects in the same field, the second one would be 2 instead of 1...

So this barbaric name allows us to know basic characteristics of the discovery.

Once the precise orbital elements are obtained, the CBAT  will assign a definitive name to the comet which, with a bit of luck, should be C/2026 A1 MAPS (A1 for first comet discovered in January 2026).

Each series of images provides three positions at three different times, at the end of the night, so there are 6 observation points for this object. NEOCP allows the creation of ephemerides (tables giving the object's position in the coming hours), access to previously reported observations of this object, and the calculation of 2000 possible orbits passing through these 6 observation points. With 2 hours of observation, it is possible to make a large number of different orbits pass through these 6 points. The MPC orbits give an absolute magnitude of 15.2 and an inclination around130 degrees, which is clearly cometary, but the local calculation with the findorb software gives more of an asteroid-type orbit, which is very common (obtaining a cometary orbit with the MPC and an asteroid orbit with findorb).

For your information, the absolute magnitude of a small body in the solar system is the magnitude (or "brightness") the object would have if it were 1 astronomical unit from Earth and 1 astronomical unit from the Sun. When measuring the magnitude of an asteroid, it is fainter the farther it is from the Sun (less illuminated) and the farther it is from Earth (also less bright). The higher the magnitude, the fainter the object. The naked eye can see up to magnitude 6 under optimal conditions; there is a factor of 100 in brightness, so an asteroid of magnitude 16 is 10,000 times fainter than what can be seen with the naked eye. Therefore, by calculation, we can find the magnitude it would have under these standard conditions, which allows us to get an idea of ​​the object's actual brightness regardless of its distance from the Sun and Earth. Today, it is very rare to discover an asteroid brighter than magnitude 18 (only two were discovered in 2025, out of more than 3,000 near-Earth asteroids). Comets, possessing an "atmosphere" (the gas emitted by the comet), are apparently brighter than asteroids. Therefore, a magnitude of 15 tells us that, if the MPC's orbit calculation is correct, it is indeed a comet.

Six numbers are needed to mathematically determine a comet's orbit, the so called "orbital elements". One of these six numbers represents the object's inclination relative to the ecliptic. Generally, asteroids, with a few exceptions, have inclinations less than 30 degrees, and the MPC's orbits around our comet are around 130 degrees for preliminary orbits, but with significant fluctuations. We are fairly certain that it is indeed a new comet, so Alain sends a cometary activity report to the MPC around 2:20 AM, describing the object.

Alain therefore went to bed without confirmation as to whether it was a comet or not. He nevertheless sent a message to Daniel Green of the CBAT (Central Bureau of Astronomical Telegrams) announcing our discovery and requesting that, once it was "officially" confirmed, it be named MAPS after our program, given that it was a collaborative effort.

The following day (the 13th), the comet was confirmed by other observers, and the MPC moved our comet from the NEOCP to the PCCP (Possible Comet Confirmation Page). However, as with all recent discoveries, it is impossible to precisely calculate the object's orbit, and therefore its future visibility, especially with comets. Since each comet is slightly different, they sometimes either "fade out," disappearing due to their proximity to the sun, or, conversely, explode and become significantly brighter (make an outburst). Hence the French expression "ne pas tirer de plans sur la comète" (don't make plans on the comet or said otherwise, don't count your chickens before they hatch).

But this is the 8th comet discovered by our program, so all three of us are very happy. 

On the night of the 14th, Alain used the 40cm telescope belonging to Joaquin Fabrega, a Panamanian amateur astronomer, to take a one-hour exposure of the comet. In practice, there were 60 one-minute exposures, centered on the comet's movement (as the comet moved across the sky, the stars appeared trailed).

Many more observations will be made by other observers around the world, which will allow us to refine the orbital parameters. Quite quickly, the inclination is approaching 144 degrees, even with findorb :), and this value is not insignificant.

Via WhatsApp, Jean François Soulier, a friend of Alain's, informed him that several people on the comet mailing list (a mailing list for comet observers) indicated that this object was likely a comet from the Kreutz group.

Kreutz's group

In the past, a number of bright comets have appeared, some with virtually identical orbital elements. This led to the idea that they are fragments of a giant comet that passed close to the Sun in 362 BC and disintegrated, with these "debris" passing close to the Sun. These are, in fact, kamikaze comets, which, if they don't fall into the Sun, pass so close that they disappear, "melting" due to the extremely high temperatures. Some of these comets have been extremely bright, some visible in broad daylight, such as comet Ikeya Seki (C/1965 S1) in 1965. The European satellite SOHO, launched in 1993, has also observed more than 5,000 comets falling into the Sun or passing very close to it, many of which belong to the Kreutz group. This short video (in English) is very interesting. At 1 minute 50, there is an animation of the solar system, where we see that the majority of comets falling on the sun are comets from the Kreutz group (the stream of comets drawn in red coming from the bottom right corner of the video). 

The orbit is probably close to this one (the orbital elements are not yet perfect, but close enough). Thanks to the Catalina Survey team for their software

If you are passionate about comets and are not afraid to spend time on reading it, there is a very comprehensive article , 21 pages in English, by Zdenek Sekanina on the comets of the Kreutz group , of which he is the recognized expert.

Normally these comets are discovered when they are very close to the sun. Ours was discovered at more than 2 AU (Astronomical Unit, i.e. the Earth-Sun distance, which in our case is more than 3 million km from Earth) and so we have 3 months of observation before it passes close to the solar furnace :) .

This page was written on the morning of January 17th. This is where we stand; our discovery certainly has a good chance of becoming quite bright, but it's difficult to know for sure. If the orbital elements are sufficiently aligned, it could be quite bright (visible to the naked eye?) towards the end of March, at dusk, except... the moon will be visible. We're keeping our fingers crossed; this page will be updated based on observations.

Alain Maury

P.S.: There are already several pages on Facebook, X, and YouTube about this comet. No one can guarantee that the comet will be spectacular, but everyone has the opportunity to say that it's a discovery made by independent/amateur astronomers, though few actually do.

PS2: If you happen to run into Avi Loeb, please tell him that it's a comet and not an alien spaceship coming to refuel on the sun :)

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