Mastodawn

The interstellar visitor #comet 3I/ATLAS is already receding far from both the Earth and the Sun, and is currently located physically near Jupiter. This animation shows the comet’s motion over roughly one hour, captured from the M00 Viestikallio remote observatory in Finland on the evening of March 7, 2026. In the inverted image, the comet’s tail is visible for about 1.5 arcminutes, and its brightness is approximately magnitude 17.5 (V).
https://www.taivaanvahti.fi/observations/show/142764

Jorma Ryske Dec 18

#Comet 3I/ATLAS image taken this morning 18.12.2025 from observatory Y71 Makroskooppi, Fregenal de la Sierra, Spain.

Tail visible at left side of the comet 3I is actually mainly anti-tail, ie dust left to comets path and visible due to orbital geometry between the Earth and the comet. Actual bluish ion tail is here very dim and short toward upper right from optocenter.

Tomorrow 19.12.2025 morning comet 3I will be at it's nearest position from Earth, 270 million km.

https://www.taivaanvahti.fi/observations/show/140355

Jorma Ryske Nov 2

Qicheng Zhang Nov 2

Interstellar comet 3I/ATLAS is now rising early enough in morning twilight to be seen even with small telescopes under imperfect conditions. Here's an image from this morning through thin clouds using a 152-mm Ritchey–Chrétien reflector.

Jorma Ryske Oct 31

Qicheng Zhang Oct 31

After passing superior conjunction last week, interstellar comet 3I/ATLAS is once again observable from the ground with optical telescopes, now in morning twilight. Here's a view from the Lowell Discovery Telescope this morning, with a ~40″ wide visible coma of r' magnitude ~10.5.

Jorma Ryske Oct 30

#Comet C/2025 A6 (Lemmon) is getting lower and lower in the evening sky. It's still observable perhaps a week ahead. Here an image of it using RGB filters taken yesterday 29.10.2025 from our observatory Y71 Makroskooppi, Spain with 0.3m telescope.

https://www.taivaanvahti.fi/observations/show/139384

Jorma Ryske Oct 30

Qicheng Zhang Oct 30

Our paper preprint on interstellar comet 3I/ATLAS brightening in view of several solar instruments was posted to arXiv yesterday: https://arxiv.org/abs/2510.25035 Paper is not yet peer reviewed, so results should be considered tentative, but the comet looks set to emerge into morning twilight within the next few days, much brighter than when it went in. It should now be at V magnitude ~9, likely with much of this brightness spread over a diffuse gas coma several arcminutes across. A bonus CCOR-1 animation and very noisy LASCO color image are included below.

Jorma Ryske Oct 14

Brightest #GRB Gamma Ray Burst found this year, #GRB251013C.

Coordinates are
R.A. (J2000) = 23h03m20.6s
Dec. (J2000) = -0d12m37.1s

Afterglow magnitude was 14.76R measured by SVOM team 261 second after gamma ray burst observed by Fermi Gamma-ray Burst Monitor (GBM) 17:39:41 UT on 13 Oct 2025.

Here my image of this GRB 251013C afterglow taken with 0.3m telescope from observatory Y71 Makroskooppi. Measured magnitude was 15.86R when exposures start 2025-10-13 19:34UT.

https://www.taivaanvahti.fi/observations/show/138641

Jorma Ryske Sep 17, 2025

Show thread

Daniel Fischer Sep 17, 2025

Amateur Milky Way observation in neutral hydrogen on steroids, with a 2.6 meter dish and superresolution: a poster at #ag2025goerlitz with detailled explanations in http://radioastronomie-leicht-gemacht.de

Jorma Ryske Sep 17, 2025

Harri Haukka Sep 17, 2025

Behalf of the #EPSCDPS2025 LOC, big thanks all of You who participated in the conference! We had amazing week in Helsinki and even the weather was gracious for us.

We had 1803 participants, 1659 attending on-site and 144 by virtually. That is a great number. Next year Europlanet will organize #EPSC in The Hague, Netherlands, and year after in Toulouse, France.

#Europlanet #Helsinki #FinlandiaHall #Finland #DPS #space #avaruus

https://www.epsc-dps2025.eu/

EPSC-DPS2025 - Home

Jorma Ryske Sep 12, 2025

Had a full week in #EPSCDPS2025 at Finlandia Hall, Helsinki. Wonderful sessions, posters and contacting "remote" friends and planetary scientists face-to-face from practically all over the world.

My own abstract and poster was there also about #comets: "Cometary ion tail observations using commercial CN narrowband UV 387nm/11nm filter", https://meetingorganizer.copernicus.org/EPSC-DPS2025/EPSC-DPS2025-628.html .

Next year #EPSC2026 will be at Hague, Netherlands.