Tootfinder

Yeah, FR, can you blame it?
#3IAtlas #AviLoeb

The #3IATLAS NASA presser has begun: https://www.youtube.com/watch?v=A55SUq2eDXg - so far they've shared this HiRISE image from Mars orbit, but they've listed many NASA s/c which have observed it.

Interstellar comet #3IATLAS webcast double feature today (19 November): first at 4:15 UTC on https://www.youtube.com/watch?v=krU8gN-J9gY the next attempt of a live observation from Italy (the first one had been clouded out) - and then at 20:00 UTC on https://www.youtube.com/watch?v=A55SUq2eDXg a NASA press conference with spacecraft observations.

All the NASA s/c images of #3IATLAS shared today (and some more) can be found at https://science.nasa.gov/solar-system/comets/3i-atlas/comet-3i-atlas-image-gallery/ now - including this spectrum from the Imaging Ultraviolet Spectrograph on MAVEN taken on 28 September, showing hydrogen emitted from different sources, namely the comet (dim spot on the far left), hydrogen from Mars (bright emission on the right), and hydrogen flowing through our solar system between the planets (dim emission in the middle).

None of the NASA s/c images of #3IATLAS shared at the presser come even remotely close in beauty - and obvious detail - to the current best ground-based images ... like this one by Michael Jäger and Gerald Rhemann with a 12-inch reflector taken this morning: https://www.facebook.com/photo/?fbid=2282405328942953

ESA’s space probe #JUICE is headed towards a truly unexpected encounter: on November 2nd, observations of interstellar object #3IATLAS will begin. Read more about contributions from #mpsgoettingen

Two competing space #webcasts in a few hours, both depending on good weather in Italy and California, respectively: #3IATLAS, and #Sentinel-6B, with a super-short launch window at 5:21 UTC.

#3iatlas
I've read that we can't observe 3I/Atlas from earth because it will be behind the sun, but according to SkyLive it looks like i should be possible to spot it from Norway still at around 1730.
If I had had a telescope, I would have tried(and likely failed).
#3i_atlas

Simultaneously NASA and ESA have published new spacecraft images of #3IATLAS, https://science.nasa.gov/blogs/3iatlas/2025/12/04/nasas-hubble-space-telescope-revisits-interstellar-comet/ from the Hubble Space Telescope on 30 November (just the inner coma with a central condensation) and https://www.esa.int/ESA_Multimedia/Images/2025/12/Comet_3I_ATLAS_shows_activity_in_Juice_navigation_camera_teaser from Juice's NavCam on 2 November with an early sighting of the plasma tail - more contributions to understanding the behavior of the interstellar visitor.

Finally an RGB image of comet #3IATLAS from images taken by #GeminiNorth during the 26 November #shadowTheScientists session: https://noirlab.edu/public/news/noirlab2532/ - the coma has become bluer due to more gas emission. Also published today: an X-ray image by XMM-Newton at https://www.esa.int/ESA_Multimedia/Images/2025/12/XMM-Newton_sees_comet_3I_ATLAS_in_X-ray_light with explanations in http://www.cbat.eps.harvard.edu/iau/cbet/005600/CBET005646.txt which also contains more 3I news.
Meanwhile the paper https://iopscience.iop.org/article/10.3847/2515-5172/ae2915 claims an upper limit for 3I's nucleus diameter of only some 750 meters from the measured non-gravitational acceleration (NGA) parameters: that would be waaay more stringent than the 5.6 km upper limit from early Hubble observations reported in https://iopscience.iop.org/article/10.3847/2041-8213/adf8d8 (where also a lower limit of 440 meters is stated).

X-ray observation of the cometary interloper C/2025 N1 (3I/ATLAS) by XRISM/Xtend: #3IATLAS from beyond the solar system: https://www.xrism.jaxa.jp/en/topics/news/1208/

And here is what comet #3IATLAS looks like for the #geminiNorth Integral Field Unit (IFU) taking numerous spectra from points across the coma - from #ShadowTheScientists

What a #GeminiNorth #3IATLAS spectrum looks like - as raw as it gets, from the #shadowTheScientists session. See https://www.astronomerstelegram.org/?read=17503 for a pre-perihelion spectrum.

The #GeminiNorth telescopes is observing the interstellar comet #3IATLAS right now: here is the acquisition image from moments ago, spectra to be taken now - from the #ShadowTheScientists session.

And here is a recording of the #ShadowTheScientists live observation of interstellar comet #3IATLAS with #GeminiNorth a few hours ago: https://www.youtube.com/watch?v=cW0chiPZyYM