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Trestan

@flare.observer
438 followers 380 following 86 posts

He/him staring at the sun academically... flare.observer

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Vincent Ledvina @vincentledvina.bsky.social · 05/10/2026
Here is what the Sun has been up to over the last seven days, as seen through its coronal holes, its sunspots, and Earth's geomagnetic activity:
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Mathew Owens @mathewjowens.bsky.social · 30/09/2026
The paper describing the new solar wind modelling framework, SURF (which includes HUXt) is published. The code is up on github and will be installable from conda and pypi in a week or so. link.springer.com/article/10.1...
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Christian Möstl @chrisoutofspace.bsky.social · 22/09/2026
Amazing new reconstruction of sunspot number for the last ~1000 years by Saha et al. 2026: link.springer.com/article/10.1...
Sunspot number since the year 971, showing several long minima and the recent, more regular solar cycles
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Guillaume Bertrand @guillaumebertrand.bsky.social · 21/09/2026
Pushing the mini SUNSCAN to its limits today: attempting a do-it-yourself solar magnetogram! 🧲☀️ Captured 3 spectra per polarization state around the magnetic-sensitive Fe I line (6302.5 Å) to measure the Zeeman splitting shift and map the magnetic field.
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Cédric Champeau @melix.champeau.me · 17/09/2026
Le diagramme que vous voyez ci-dessous est, si je ne me trompe pas, une première mondiale : la mesure par un astronome amateur des oscillations périodiques du soleil (toutes les 5 min environ). Je vous explique tout ça dans ce billet : melix.github.io/blog/2026/09... #astronomie #science
Un diagramme taille-fréquence des oscillations solaires, montrant un pic à ~3mHz, soit environ 5 minutes.
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Trestan @flare.observer · 10/09/2026
The reaction-diffusion style patterns that form in the background are interesting. A similar pattern forms when you repeatedly blur and sharpen an image.
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Trestan @flare.observer · 07/09/2026
I recently switched to Arch Linux after 7 years of using Gentoo (all of high school and 3/4 of college!) because I still need Qt 5 for a little while longer. It's not so bad!
A screen capture of an Arch Linux desktop. There is a taskbar at the top of the screen and a terminal (kitty) at the center. The terminal displays some system information using fastfetch. The taskbar and terminal are both blue, and the wallpaper is a photo of the Earth taken from the ISS, https://commons.wikimedia.org/wiki/File:ISS-40_Blue_and_white_part_of_Earth.jpg
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THE FAR SIDE DAILY @bot.cowtools.org · 03/09/2026
Inside the sun
Inside the sun
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Trestan @flare.observer · 26/08/2026
You are using seximal.
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Trestan @flare.observer · 22/08/2026
Very nice! The large prominence that you captured looks like it might actually be coronal rain associated with today's M1.6 flare. Cold plasma condensates ("rain") sometimes form in post-flare coronal loops and fall down along the loop legs, making the post-flare magnetic structure visible in Hα.
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Trestan @flare.observer · 18/08/2026
You might be seeing the Summer Triangle. lt is not one of the 88 officially recognized constellations, so it is usually referred to as an asterism. The three stars forming the triangle are the brightest in their respective constellation, so it stands out quite nicely even in urban areas.
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Christian Fröschlin @chrfrde.bsky.social · 12/08/2026
Time lapse of first half of today's partial solar eclipse as seen from The Hague. 310 x 165 x 1.2 ms Ha < 0.7 Å in Lunt 40 at f/10. #astrophotography
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Trestan @flare.observer · 11/08/2026
Inverted and grayscale versions
Same as original image but with inverted colorsSame as original image but in grayscale
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Trestan @flare.observer · 11/08/2026
Large solar prominence from 2024-03-24 ☀️🔭
Red false-color image of a large solar prominence captured with an amateur Hα telescope. The solar disk, which was overexposed, has been masked.
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Robin Bradshaw @en4rab.bsky.social · 07/08/2026
Its Friday night and time to go wild! So here is an x-ray of a packet of McCoy's Thai sweet chicken crisps
An xray of a packet of ridged crisps showing lines of grey where the ridges make the crisp thicker and speckles of white i think where the salt has absorbed the xrays
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Max Planck Institute for Solar System Research @mpsgoettingen.bsky.social · 05/08/2026
Using the #InouyeSolarTelescope and computer simulations, researchers from #NationalSolarObservatory, #mpsgoettingen and #HighAltitudeObservatory reveal tiny vortices on the Sun’s surface. They are signs of Kelvin-Helmholtz instabilities. Published today in @nature.com . Video: NSF/NSO/AURA/MPS
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Trestan @flare.observer · 29/07/2026
We have already used the SADCat to uncover new relationships between SAD appearance and flare X-ray and coronal mass ejection characteristics, and we are excited to see what further advances this resource enables in the future. 4/4 Paper link (open access): doi.org/10.1007/s112...
doi.org
SADCat: A Catalog of Supra-Arcade Downflow Events in Solar Flares - Solar Physics
Supra-arcade downflows (SADs) are sunward-traveling features routinely observed in hot fan structures above magnetic loop arcades during eruptive solar flares. We manually compiled a catalog (SADCat) of 178 SAD-productive flares imaged by the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory (SDO) during solar cycle 24 as a resource for the wider solar flare community. We conducted a preliminary analysis of the SADCat, comparing the flare X-ray and CME properties between eruptive solar flares with and without SADs. We found that peak GOES X-ray flux, flare duration, CME speed, and CME mass have a strong influence on whether a flare produces visible SADs, whereas flare impulsivity and CME acceleration have little effect.
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Trestan @flare.observer · 29/07/2026
but individual observations offer only a limited view. By bringing together a large collection of SAD events, the SADCat serves as a new resource for investigating these elusive features across a diverse population of solar flares. 3/4
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Trestan @flare.observer · 29/07/2026
SADs, or supra-arcade downflows, are dark, teardrop- or tadpole-like voids that descend through the solar corona toward bright post-flare loops. They provide important clues about the processes that convert magnetic energy into heat and motion during solar flares, ... 2/4
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Trestan @flare.observer · 29/07/2026
My first first-author paper, "SADCat: A Catalog of Supra-Arcade Downflow Events in Solar Flares", is now published in Solar Physics! Dr. Ryan French (@ryanjfrench.bsky.social) and I present a catalog of 178 solar flares with visible SADs as a resource for the broader solar flare community. ☀️ 1/4
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Marijke Louise @marijkelouise.bsky.social · 21/07/2026
Zonnevlek 4493. Maximilian-Vlad Teodorescu fotografeerde de 100.000 kilometer brede structuur vanuit het Instituut voor Ruimtewetenschappen in Roemenië. De aarde bevindt zich rechtstreeks in de inslagzone als er vandaag een X-vlam plaatsvindt. #SpaceWeather
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Trestan @flare.observer · 23/07/2026
Growth and evolution of NOAA solar active region 14493 in the corona (left; extreme ultraviolet, SDO/AIA 211 Å) and its associated sunspots in the photosphere (right; visible light, SDO/HMI continuum) between 2026 July 18 and 22. ☀️🔭
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Trestan @flare.observer · 22/07/2026
Sunspots, filaments, and plage flanking the eastern arc of the solar equator captured yesterday (2026-07-20) in Hα and oriented so that the equator splits the image vertically down the middle. ☀️🔭
A false-color red Hα image of the Sun's eastern equatorial region rotated 90° clockwise (i.e., south is left and north is right). Prominent bright plage are visible to the south of the equator with dark filaments weaving between individual bright patches. A single active region is visible north of the equator with two large sunspots. To the west of the active region is a large jagged-looking filament.
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Trestan @flare.observer · 18/07/2026
More from this morning
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Trestan @flare.observer · 18/07/2026
Wildfire smoke and clouds passing in front of the Sun this morning
A photo of the sky. The Sun appears at the center of the image as a bright featureless disk. Wildfire smoke and clouds are spread across the sky giving the solar disk an orange tinge. The image is framed by the silhouettes of leaves and branches.
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Trestan @flare.observer · 16/07/2026
Light wildfire smoke over New Jersey this afternoon
Clouds and the afternoon sun viewed through light wildfire smokePetting a black cat lying on its back. Its green eyes are looking up at the sky.
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Cédric Champeau @melix.champeau.me · 06/07/2026
Ca n'est pas pour me vanter (un peu quand même), mais cette image de la couronne solaire chaude (dite couronne K) est probablement une des plus résolues jamais faites en amateur. Le niveau de signal recherché ici est environ 1 million de fois plus faible que celui de la photosphère.
Une image du soleil. Le disque est masqué artificiellement. Autour, elle montre la couronne solaire chaude, dite couronne K, avec un niveau de détail important. Cette image a été obtenue depuis le sol, en dehors de toute éclipse.
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Vincent Ledvina @vincentledvina.bsky.social · 30/06/2026
The birth of AR 4479--like cells dividing--here are the last six days. This region possesses a 5% chance of an X-flare over the next 24 hours and has been increasing in notable flare activity recently. It is in the Earth-strike zone and positioned well for Earth-directed flare+CME activity.
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Astronomy Picture of the Day 🪐 @apod.shinyakato.dev · 28/06/2026
🔭 AR 4478: Giant Sunspot Group Image Credit & Copyright: Alfredo Vidal Pérez ap260628
The Sun is pictured in yellow with surface structure.
In the middle of the frame are many circuitous dark spots.
The edge of the Sun is visible at the top of the image. 
Please see the explanation for more detailed information.
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Mike Christie @mikechristie.bsky.social · 26/06/2026
I hadn't processed all the video I took of the Sun yesterday. This is a sequence of images (13:57, 14:00, 14:02, 14:17) showing how rapidly that large prominence changed and disappeared. #Coronado Solarmax 🔭 and a #TeleVue 2.5x Powermate. #heliophysics #astrophotography
Prominence at 13:57Prominence at 14:00Prominence at 14:02Prominence disappeared at 14:17
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Trestan @flare.observer · 24/06/2026
The solar wind may be a plausible source as well! www.nature.com/articles/s41...
nature.com
Solar wind contributions to Earth’s oceans - Nature Astronomy
Water and hydroxyl enrichment in the solar-wind-irradiated rim of an olivine grain from asteroid Itokawa suggests that its regolith could contain ~20 l m−3 of water from solar wind—a potential water s...
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Vincent Ledvina @vincentledvina.bsky.social · 20/06/2026
Spending my Saturday today creating some better visualizations of aurora chasing tools such as how auroral substorms are correlated with GOES Mag readings. Here is an example where GOES Mag is well-correlated. Substorm initiation is around the same time as the spike in GOES Mag readings.
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Trestan @flare.observer · 09/06/2026
Testing the new carousel feature. Also, "10 billion K" should be "10 million K".
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Trestan @flare.observer · 09/06/2026
The Sun today in the seven SDO/AIA extreme ultraviolet bands from hottest (flaring plasma at ~10 billion K) to coolest (chromosphere plasma at ~10,000 K) plus SDO/HMI continuum. ☀️🔭
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Catherine Ryan Hyde @catherineryanhyde.bsky.social · 07/06/2026
I thought today's sun was an interesting example of how active regions often form in lines or bands. #Astronomy #AstroPhotography
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U.S. Consumer Product Safety Commission @cpsc.gov · 29/05/2026
There are secrets in the Sun.
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Vincent Ledvina @vincentledvina.bsky.social · 17/05/2026
Monster sunspots on the Sun's farside right now! Take a look at the most recent solar orbiter image showing a giant group of sunspots, perhaps two active regions. This has been generating large solar flare >X-class and CMEs. It will be visible on the Earth-facing disk in about a week or so.
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Burr Ito @ututuy.org · 02/05/2026
That the sun is a star like the ones we see at night is something that will never stop being astonishing to me. Its surface has a texture, the solar granules, which are the result of very strong convective motion. The sunspots are magnetic anomalies, a bit cooler than their surroundings. 🧪 🔭
Partial image of the solar disc using a telescope and an infrared filter (IR 850 nm pass filter). The sun appears yellow and with a sort of texture (the solar granules). There are also some sunspots. In the center of the pic is the sunspot group denominated AR 4225.
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Trestan @flare.observer · 23/04/2026
The decaying solar active region that formed within a coronal hole from last week sans JP2 compression artifacts ☀️
Pink false-color image of a solar active region as it appeared in the SDO/AIA 211 Å filter on 2026-04-14.
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Dr Adam J. Finley @adamfinley.bsky.social · 20/04/2026
A great review of the proposed mechanisms for switchback formation in the solar wind. These strong deflections in the local magnetic field are ubiquitous close to the Sun and have been linked to the heating and acceleration of the solar wind. arxiv.org/pdf/2604.16166
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Trestan @flare.observer · 18/04/2026
Yes, I believe so! The high-speed solar wind originates from coronal holes, and larger coronal holes are generally associated with faster peak solar wind speeds. For Earth, faster solar wind speeds result in more intense aurora (via more intense substorms).
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Trestan @flare.observer · 18/04/2026
This region is likely the decaying remains of AR 14400 which we saw emerge within a coronal hole about one solar rotation ago (~27 days). ARs that form in this way typically have loops that fan out in all directions from the region's center like the tentacles of a sea anemone, hence the term.
False-color full-disk image of the Sun as it appeared on 2026-03-21. AR 14400 appears at the center of the solar disk as a small bright patch surrounded on one side by a dark coronal hole. The image was taken by SDO/AIA in 211 Å.False-color full-disk image of the Sun as it appeared on 2026-04-17, a full solar rotation after the previous image. AR 14400 again appears at the center of the solar disk but this time as a more diffuse bright patch surrounded on all sides by a dark coronal hole. The image was taken by SDO/AIA in 211 Å.
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Trestan @flare.observer · 18/04/2026
Fittingly, the patch of bright loops in the lobster coronal hole's clutch is a decaying anemone region. ☀️
False-color image of the anemone active region. The region appears as a patch of bright coronal loops almost completely surrounded by a dark coronal hole. The image was taken by SDO/AIA in 211 Å on 2026-04-14T20:01 UT.
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Trestan @flare.observer · 13/04/2026
Note that the severity of these GICs depends a lot on geography. I would recommend checking out the NWS and FEMA resources linked below if you are concerned. www.weather.gov/safety/space... www.ready.gov/space-weather
weather.gov
Before an Extreme Solar Event
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Trestan @flare.observer · 13/04/2026
Devices not plugged-in should be safe, while those plugged-in might experience voltage spikes/instability as a secondary effect of geomagnetically induced currents (GIC) along long-distance transmission lines. Your devices will effectively be isolated from any direct GIC flow, however.
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Trestan @flare.observer · 13/04/2026
Geomagnetic storms from CMEs only induce damaging electrical currents in long electrical conductor systems like power transmission lines and oil and gas pipelines. Personal electronics are too small for any appreciable current to form and should be safe even during a severe storm.
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Trestan @flare.observer · 12/04/2026
Try looking in infrared. en.wikipedia.org/wiki/Hot%2C_...
en.wikipedia.org
Hot, dust-obscured galaxy - Wikipedia
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Don Davis @ddavisspaceart.bsky.social · 09/04/2026
The view of the Solar corona the Artemis II Astronauts had just after the Sun went behind the Moon. I have brought out the delicate fan like radial detail of the Sun's corona, whose entire span can be seen during Total Solar Eclipse from Earths surface where the Moon happens to just cover the Sun.
This is a photograph made by the Artemis II crew just after the Sun went behind the Moon from their vantage point. The inner Zodiacal Light and outer corona form a diffuse glow around the hidden Sun, from which radiates spikes and a general radial texture whose details constantly change.
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Vincent Ledvina @vincentledvina.bsky.social · 06/04/2026
Adding in the COSMO K-COR coronagraph fills in the lower corona which is a crucial region to not only detect CMEs soon after they launch off from the Sun but also understand their rotations and twists as they are steered by magnetic fields before traveling further into space.
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NSF NCAR & UCAR @ncar-ucar.bsky.social · 01/04/2026
We’re not foolin’ you! The Mauna Loa Solar Observatory (MLSO) has officially reopened in time to assist NASA’s Artemis II mission with space weather warnings! It has been closed since Mauna Loa’s 2022 eruption blocked the road, making the site accessible only by helicopter for special operations.
The Mauna Loa Solar Observatory site.New road to MLSO
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