Trygve Prestgard

Comet C/2025 A6 (Lemmon) is entering the STEREO/SECCHI HI1-A camera's FOV! So far, only low-quality data is available. ☄️
#CometWatch

Image of comet C/2018 V1 on 2018 Nov 18, by Michael Jäger, https://fg-kometen.vdsastro.de/pix/test/bild.php?nr=20224

#bskycometography no. 356

C/2018 V1 (Machholz-Fujikawa-Iwamoto)

2018 Nov 7: Disc by D. E. Machholz (visual), S. Fujikawa & M. Iwamoto (Japan) at 10 mag. It's the last visual comet discovery! Perihelion on Dec 3 at 0.39 au w/ 7-8 mag. Last seen on Dec 17, possibly disintegrated.
☄️🔭 #CometWatch

Image of C/1948 V1 taken from an airplane, image from https://skyweek.wordpress.com/2013/12/26/es-geschah-vor-65-jahren-mysterium-um-die-luft-aufnahmen-des-letzten-finsterniskometen/ by @cosmos4u.bsky.social, also https://www.rocketstem.org/2020/05/16/ice-and-stone-special-topic-21/

#bskycometography no. 350

C/1948 V1 (Eclipse Comet)

1948 Nov 1: Disc on photographs taken during the total solar eclipse at 2° from the sun at maybe -3 mag. From Nov 5 seen from the ground. Max tail ~20°. Perihelion on Oct 27 at 0.14 au. Last seen 1949 Apr 3. ALT for image source.
☄️🔭 #CometWatch

Development of brightness and size of comet 17P/Holmes during the ourburst of 2007 by Naoyuki Kurita, https://stellarscenes.net/comet_e/holmes_change.htm

#bskycometography no. 355

17P/1892 V1 (Holmes)

1892 Nov 6: Disc by E. Holmes (England) at 4 mag while in outburst five months after perihelion (Jun 13 at 2.14 au)! The comet faded slowly while becoming larger and diffuse. 2nd outburst on 1893 Jan 16. P=6.90 y, recovery in 1899.
☄️🔭 #CometWatch

Image of comet C/1975 T2 (Suzuki-Saigusa-Mori) by Maurice Clark on 1975 Nov 4, http://www.phys.ttu.edu/~ozprof/ssm1.htm

#bskycometography no. 323

C/1975 T1 (Mori-Sato-Fujikawa) & C/1975 T2 (Suzuki-Saigusa-Mori)

1975 Oct 5: Two comets discovered within 1 hour by numerous Japanese comet hunters! Mori found his two comets within 70 minutes! The comets reached 8 mag and 4 mag, respectively.
☄️🔭 #CometWatch

C/1577 V1 over Prague on 1577 Nov 12, broadsheet, Von einem schrecklichen und wunderbarlichen Cometen so sich den Dienstag nach Martini dieses lauffenden M. D. LXXViJ. Jahrs am Himmel erzeiget hat. (Geschrieben von Peter Codicillus von Tulechova), Zentralbibliothek Zürich - Von einem schrecklichen und wunderbarlichen Cometen so sich den Dienstag nach Martini dieses lauffenden M D LXXViJ Jahrs am Himmel erzeiget hat - 000003593.jpg

#bskycometography no. 351

C/1577 V1

1577 Nov 2: First seen from Peru at maybe -7 mag! Quickly seen world-wide. Perihelion on Oct 27 at 0.18 au, perigee on Nov 10 at 0.62 au. Used to prove for the first time that comets are outside of Earth's atmosphere. Last seen on 1578 Jan 26.
☄️🔭 #CometWatch

Cute! 😍 Yesterday a small Kreutz-group comet discovered in CCOR-1 was found to be "double" when it entered the SOHO/LASCO C2 FOV! Close sungrazer fragments are personally my favorite! ☄️☄️
#CometWatch #Sungrazer

Image of comet C/1963 R1 as photographed from north of Los Angeles by Alan McClure on September 21, 1963. Photo copyright Alan McClure, https://www.rocketstem.org/2020/10/24/ice-and-stone-special-topic-44/

#bskycometography no. 302

C/1963 R1 (Pereyra)

1963 Sep 14: Discovered by Z. M. Pereyra (Argentina) at 2 mag. This member of the Kreutz group of sungrazing comets had passed perihelion already on Aug 23 at 0.005 au. Max tail length ~18°. The comet was last seen on Dec 18.
☄️🔭 #CometWatch

And also congratulations to our #post-doctorate members (Lisa, Samuele, and @trygveprestgard.bsky.social) for presenting their ongoing work on fossil micrometeorites! ☄️
@amgc-vub.bsky.social

Lastly, the FLUX PhD and Post-docs wrapped up their week at the #EPSC with a few group photos! 📸 ☄️😀
@amgc-vub.bsky.social
@fienjo.bsky.social
@trygveprestgard.bsky.social

Discovery image of comet C/1996 R3, https://web.archive.org/web/20070611074815/http://www.astro.uu.se/~classe/comet/com2.html

#bskycometography no. 301

C/1996 R3 (Lagerkvist)

1996 Sep 13: Disc by K. I. Lagerkvist (Chile) at 18.5 mag. The comet was well past perihelion (1995 Jul 20 at 5.21 au) and did not become brighter. Last seen Oct 30. I was involved with orbit improvement (see link in ALT text).
☄️🔭 #CometWatch

A Bright New Comet Discovered in SOHO/SWAN Images! While comets such as 3I/ATLAS and C/2025 A6 (Lemmon) have currently been our main focus, it turned out that another interesting object — magnitude +7 — was quietly lurking in daylight! Provisionall…

Surprise! A bright new comet is entering darker skies, with a relatively close approach with Earth (~0.25 AU) in October! Read more about this discovery (provisionally designated SWAN25B) in my latest blog post! 😄
#CometWatch #ESA #NASA

About 37 years ago, the final moments of #comet C/1988 Q1 were captured by the Solar Maximum Mission. The below animation contains the only images of this sungrazer, which may have reached negative magnitudes prior to disintegrating! Image credit: The HAO/SMM C/P project team & #NASA
#CometWatch

Ok thanks! Yes it's the same comet. First Jiangao probably assumed it was a non-group before realizing it was a Kracht-II fragment. Speaking of which, I see yet another one has been recovered or discovered! Looks like P/2002 R5 either fragmented again, or, we missed some in 2019.

From which date is this Non-group? :)

Yayy more #Raman spectroscopy of #micrometeorites! 😁☄️

Yesterday a fragment of Kracht-II group comet P/2002 R5 (SOHO) was reobserved! This periodic comet likely split in 2002 and was recovered as two fragments in 2008, then as four in 2014 and 2019! It was recovered in public data from the CCOR-1 telescope, but was also visible in LASCO. ☄️
#CometWatch

Image of comet 115P/Maury of 2020 July 19 by Michael Hauss, https://fg-kometen.vdsastro.de/pix/test/bild.php?nr=24422

#bskycometography no. 271

115P/1985 Q1 (Maury)

1985 Aug 16: Discovered by A. J. Maury (USA) on POSS plates at 16 mag. The comet was past perihelion (Jun 8 at 2.01 au) and did not become brighter. It was last seen on 1986 Jan 7. Period 8.84 years. The comet was recovered in 1994.
☄️🔭 #CometWatch

Today SOHO/LASCO C3 caught this cool image of a bunch of dust passing infront of the camera. It's likely the result of debris released by the spacecraft's insulation layers from a tiny micrometeorite impact. ☄️

Yes I'm still somewhat active, just less than before. I do however follow what goes on! Speaking of which, a late-congrats on your two recent sungrazers! ☄️☄️

Hello @landing-no-blue.bsky.social! Despite its brightness, it was probably no more than a few tens of meters in diameter. 😊☄️

Nine years ago this beautiful Kreutz-group sungrazer (SOHO-3109) was plunging towards its demise! Likely reaching mag 0 at its brightest, it is one of the brightest SOHO-discovered comets ever observed! ☄️ #CometWatch

Schematic illustration of a star penetrating the Oort cloud. Image adapted from Higuchi & Kokubo (2020)

WE PUBLISH: INTERSTELLAR VISITORS AND ELUSIVE EXTRASOLAR METEORITES to exemplify how Oort cloud objects gravitationally perturbed by stellar encounters can simulate interstellar visitors:
www.astroscu.unam.mx/rmaa/RMxAC.....
Based in our #Icarus journal paper:⤵️
www.sciencedirect.com/science/arti...

Had a really nice time at #Goldschmidt2025 in Prague! 😁

Composite of archival images of comet C/1951 G1 (Groeneveld), G. W. Kronk, images courtesy of the Yerkes Observatory, operated by the Department of Astronomy and Astrophysics, University of Chicago, these were found and measured by Gary Kronk and myself to allow naming of this comet

Ingrid van-Houten-Groeneveld, By Carl Koppeschaar, CC BY-SA 2.5, https://commons.wikimedia.org/w/index.php?curid=40998748,

#bskycometography no. 136

C/1951 G1 (Groeneveld)

1951 Apr 2: Disc by I. Groeneveld (USA) as a 15 mag small diffuse object. Announced in 1954 as unconfirmed. Finally confirmed by G. W. Kronk & yours truly in further images of the same survey (Mar 31-Apr 7). Announced in 2023.
☄️🔭 #CometWatch

How amazing! The Great Comet of 1744 appears to be periodic, with an estimated return in 2097! ☄️😀
#CometWatch

We are happy to end this week with a "family photo" of most FLUX (and related) team members! Despite the Sun being absent, our smiles remained present! A big thanks to Jean-Guillaume Feignon for the photo 😄☄️

It's nearing the end of another productive week! Today's post features @fienjo.bsky.social and Samuele hunting for cosmic spherules, as well as @trygveprestgard.bsky.social measuring micrometeorites using the Raman spectrometer! Included is also an image showing *some* finds made by Sam this week!

It's great using the Raman spectrometer again! 😀

Amateur Astronomers are Discovering Comets in Online Data from the GOES-19 Satellite! After only two months of making their data publicly accessible, almost thirty previously-unknown sungrazing comets have been identified in images obtained by the GOES-19 satellite! All these comets…

Did you know anyone can discover comets in images taken by the CCOR-1 telescope aboard @noaa.gov's #GOES-19 satellite? Read more about the early success of CCOR-1 as a comet hunting tool in my latest blog post! 😃☄️ #CometWatch skyhuntblog.wordpress.com/2025/03/30/a...