Tootfinder

Sequential Fragmentation of C/2025 K1 (ATLAS) After Its Near-Sun Passage: #comet breaking up: https://esahubble.org/news/heic2606/ and https://science.nasa.gov/missions/hubble/nasas-hubble-unexpectedly-catches-comet-breaking-up/ (the paper as submitted had been discussed by me last November in https://skyweek.wordpress.com/2025/11/26/heute-beginnt-die-tagung-des-esa-ministerrats/ - "So sah Hubble den Kometen C/2025 K1 (ATLAS) zerbrechen").

Today it took Michael Jäger and Gerald Rhemann a 12-inch telescope and 27 minutes of total exposure time to show #comet C/2025 R3 (PANSTARRS) this nicely: https://www.facebook.com/photo/?fbid=2382646772252141 - but if it stays the course (brightness-wise speaking) it could be quite impressive for much smaller gear as well as the human eye just a month from now.

Attempting to pick #comet C/2025 R3 (PANSTARRS) ouf of dawn today in MŸn at 55°N, at 4:13, :33 and :39 CEDT: solar depressions 14.5°, 12 1/3° and 11 3/4°, comet elevations 7 1/3°, 10° and 10 3/4° - so darker sky is more important that higher elevation. Visually the comet was underwhelming in 11x70 binoculars: that's certainly one for (bigger) cameras, not the eye. And the viewing window is closing fast anyway.

Prospects for #Comet C/2026 A1 MAPS - a comet with a narrow tail in the evening twilight, with uncertain but potentially high brightness? https://hdr-astrophotography.com -> Tail simulations for comet MAPS: https://groups.io/g/comets-ml/message/34888 - in order not to depend on a single prediction, i have simulated different scenarii.

The uncertain brightness and tail(s) development of #Kreutz #comet C/2026 A1 (MAPS) is one thing - see the curves in https://astro.vanbuitenen.nl/comet/2026A1 and https://aerith.net/comet/catalog/2026A1/2026A1.html for guesses and https://cobs.si/obs_list?id=2688 for the current value which is ~8.5 mag. - but the viewing geometry is the other: here it is for 51.5° North (my place Bochum) and 22.5° South (Windhoek) as the view is much better from the southern hemisphere.
The table first gives the elongation (angle between comet and Sun in the sky) and the phase angle (the angle Sun - comet - Earth) which nearing 180° can lead to significant boost of brightness by forward scattering on dust.
And this is followed by the altitude of the comet at the solar depressions given in the top line, for Bochum and Windhoek: sunset and end of civilian twilight and for the latter also the end of nautical and astronomical twilight, i.e. the onset of night. Also of importance is the angle of a hypothetical dust tail (simulated in https://hdr-astrophotography.com) after perihelion, also much better in the South: https://britastro.org/section_news_item/c-2026-a1-maps-a-kreutz-group-sungrazer - but first MAPS has to survive the latter *and* release a lot of dust at the right time ...

So the new #Kreutz #comet #MAPS is *still* following the constant rapid rise in brightness it has shown since discovery: a dumb extrapolation - https://cobs.si/analysis/?comet=2688&from_date=2026-01-15 00:00&to_date=2026-04-30 00:00&observation_type=V&observation_type=C&plot_x_value=1&plot_y_value=1&fit_option=1&exclude_faint=on&exclude_issue=on&observer=&association=&country=&compare_values=compare - has it get 10,000-times brighter than the Sun at its extremely close perihelion which makes so sense at all, of course, physically.
"It must therefore be assumed that this increase in activity will level off significantly in the near future," writes https://fg-kometen.vdsastro.de/koj_2026/c2026a1/26a1eaus.htm: "More likely are parameters m m0=12.0 mag / n=4 (or even lower), which would still result in a (very short-term) maximum brightness of about –9 mag (but this would probably still be significantly too bright) – always assuming that the comet survives its perihelion passage unscathed."
For other views see http://www.cbat.eps.harvard.edu/iau/cbet/005600/CBET005663.txt and https://arxiv.org/abs/2602.17626 and https://www.facebook.com/photo?fbid=10236580364221799 and https://cometografia.es/cometa-kreutz-2026-a1-maps-analisis/ - and the actual brightness is tracked at https://cobs.si/obs_list?id=2688 where it has reached ~11.5 mag. now.

A clear detection of #comet C/2025 R3 (PANSTARRS) on the morning of March 2 "despite the 99% illuminated Moon, morning twilight and the comet at an altitude of 4.2 degrees": https://groups.io/g/comets-ml/message/34974 -> "The fact that the comet is showing this much detail under such bad conditions with such bad equipment and software bodes well for what we expect will be a very nice comet in the next few months."

The most interesting #comet right now, C/2025 R3 (PANSTARRS), imaged by Michael Jäger and Gerald Rhemann on the morning of 9 April in Martinsberg, Lower Austria with a 12"/4 Lacerta-Newton QHY 600 - the brightness at that time was around 5.5 mag. so the hoped-for forward scattering surge is much subdued ... too little dust in the coma? If it stays that way the coma brightness would only rise by another magnitude or so before the comet is lost in the twilight mid-month - but enjoy its great plasma tail (even accessible to low-end smart telescopes, by the way) while you can.

40 years ago tonight the #Giotto spacecraft passed the nucleus of #comet #Halley at great speed: the documentary https://www.youtube.com/watch?v=eI-W8ss4x5I from back then - also at https://www.esa.int/ESA_Multimedia/Videos/Undated/Giotto_-_English with bonus material - tells the story well. A big special issue of the ESA Bulletin about the mission is at https://esamultimedia.esa.int/multimedia/publications/ESA-Bulletin-046/offline/download.pdf and other historical material like some photos is linked from https://historicalarchives.esa.int/giotto-cometary-encounters-and-archival-sources while a recording of the BBC's live coverage is at https://www.youtube.com/watch?v=QxDMdH4uzxI

#Comet C/2024 E1 (Wierzchos) and #Galaxy NGC 55
Date: 11 02 2026 UT 18:39
Location: Farm Tivoli, #Namibia
Telescope: ASA Astrograph 12" f3.6
Camera: ZWO ASI 6200 MM Pro
Mount: ASA DDM 85
Exp.Time: LRGB 10/2/2/2 min.
Gerald Rhemann and Michael Jäger

🇺🇦 #NowPlaying on #BBC6Music's #RileyAndCoe
Comet Gain:
🎵 Seven Sisters To Silverlake
#CometGain
https://comet-gain.bandcamp.com/track/from-seven-sisters-to-silverlake
https://open.spotify.com/track/09hOsne5O1atEiTWNioBhk

🇺🇦 #NowPlaying on BBCRadio3's #NightTracks
Giovanni de Macque & Comet Musicke:
🎵 Capriccio sopra re fa mi sol
#GiovannideMacque #CometMusicke
https://open.spotify.com/track/7L5gttBpYVK8oKoJY2e7wq

The #Kreutz #comet #MAPS "has become more than 1 mag brighter between March 6 and 9" and stands at 10.5 mag. right now: https://groups.io/g/comets-ml/message/35019 and https://www.facebook.com/photo/?fbid=2374472359736249 with the latest picture by Jäger & Rhemann here - less than 4 weeks til perihelion, and the brightness continues to rise with a strong n~8 ...

The *other* potentially quite interesting April #comet C/2025 R3 (PANSTARRS) has been recovered in morning twilight: https://groups.io/g/comets-ml/message/34973 - it "has brightened nicely since my last observation on February 9 when it was in evening twilight at magnitude 13.3, magnitude calculations on the mornings of February 27/28 found the comet at magnitude 11.1 and 10.7 but I am sure the coma is a lot bigger and not fully reflected in these magnitude measurements."

Reversal of Spin - #Comets 41P/Tuttle–Giacobini–Kresak: https://iopscience.iop.org/article/10.3847/1538-3881/ae4355 -> Hubble Detects First-Ever Spin Reversal of Tiny Comet: https://science.nasa.gov/missions/hubble/nasas-hubble-detects-first-ever-spin-reversal-of-tiny-comet/

What #comet C/2025 R3 (PANSTARRS) - more pictures from the 28th in https://www.danilopivato.com/solar_system/comets/c2025_r3_panstarrs/2026.03.28.html and https://www.facebook.com/photo/?fbid=34496897756622967 and https://x.com/hositosorekara/status/2037645491253780614 and https://www.facebook.com/groups/227002358661288/posts/1726756352019207 - may be up to brightness-wise and what the viewing geometry will be in central Europe: explanations in https://skyweek.wordpress.com/2026/03/26/allgemeines-live-blog-ab-dem-26-marz-2026/#Mar29

Lots of fascinating detail in the plasma tail of #comet C/2025 R3 (PANSTARRS) this morning in an image by Christoph Gerhard with a 30-cm telescope: https://www.klostersternwarte.de/aktuelles/ein-überraschender-komet-c-2025-r3-panstarrs - this one will stay with us (Northerners) for another three week low before/at dawn before getting lost in the Sun's glare (when dust forward scattering could brighten it even more).

For optics large enough there is an amazing #comet in the - southern - sky right now, C/2024 E1 (Wierzchos): an image taken by Gerald Rhemann and Michael Jäger remotely in Namibia, https://www.facebook.com/photo/?fbid=25304451112588622
Date: 26 01 2026 UT 18:47
Location: Farm Tivoli, Namibia
Telescope: ASA Astrograph 12" f3.6
Camera: ZWO ASI 6200 MM Pro
Mount: ASA DDM 85
Exp.Time: LRGB 7.8/5/5/5 min.

Whatever eagerly awaited #Kreutz #comet C/2026 A1 (MAPS) is up to - see also https://groups.io/g/comets-ml/topic/118409957 and https://nitter.net/JAtanackov/status/2035718257060036738 and https://scicomm.xyz/@qicheng@cometary.org/116262858373488354 - less than two weeks from perihelion, it has developed a long plasma tail now: https://www.facebook.com/photo/?fbid=25816609931372735 (Rhemann & Jäger yesterday with a 12 inch telescope; full and detail).

The new #Kreutz #comet discovered unusually early has been named C/2026 A1 (MAPS): #photosphere on 4 April and becoming a bright comet.

The new #Kreutz #comet is now C/2026 A1 (MAPS): http://www.cbat.eps.harvard.edu/iau/cbet/005600/CBET005658.txt and #perihelion is highly uncertain but there is hope as https://www.facebook.com/groups/227002358661288/posts/1670699484291561 and https://groups.io/g/comets-ml/topic/117373975#msg34667 explain. And if MAPS makes it to perihelion and is (very) bright then coronagraphs on the ground might be able to catch it against the inner corona as the following table - calculated with https://ssd.jpl.nasa.gov/horizons/app.html#/ - shows.