Cédric Champeau
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melix.champeau.me
Cédric Champeau
@melix.champeau.me
He/Him. Software Engineer at #OracleLabs, formerly #Gradle. Amateur astronomer. Author of #JSolEx (solar image processing for spectroheliographs). Opinions are my own.
Avant 2024, personne n'utilisait le terme "narcotrafic". On utilisait "trafic de drogue". Il ne fait aucun doute que le changement correspond aussi à une volonté politique, celle-là même qui veut nous imposer une vision où l'insécurité est partout. Effrayer la population en changeant les mots.
February 12, 2026 at 10:14 AM
Was super lucky to visit the CERN CMS experiment today! Tomorrow I will give my presentation about JSol'Ex at Voxxed Days, very exciting!
February 9, 2026 at 9:09 PM
Measuring solar differential velocity with a spectroheliograph, right on time for Voxxed Days CERN! melix.github.io/blog/2026/02...

#jsolex #spectroscopy
February 5, 2026 at 11:17 PM
I will have the great honor to give a talk at Voxxed Days CERN on February 10th, about #JSolEx, the solar image processing software I wrote for spectroheliographs! If you are curious about solar physics, this is an opportunity to learn!
January 23, 2026 at 9:34 AM
The Flaming Star Nebula, mosaic of 2 panels.

Details on my Mastodon account: mastodon.xyz/@melix/11581...
December 31, 2025 at 9:18 AM
I am mind blown. I asked Claude to port Ratatui to Java, using Gradle, create a demo app and compile it to a native binary. It took 20 minutes. Here's the demo (this is a native binary compiled using GraalVM using the official native build tools plugin). 🫳🎤

/cc @glaforge.dev @maxandersen.xam.dk
December 19, 2025 at 4:18 PM
And here you get the result of stacking. The first image is with classic processing, the second one has unsharp masking and proms enhancement. All this was obtained without use of other software, because I'm lazy and I like automation offered by JSol'Ex scripts :)
December 14, 2025 at 8:06 PM
I often see that folks use AS! to stack their SHG images. However, the algorithm in JSol'Ex is very capable. Here's an example with 6 images from today. In the animation, on the left, you can see the images "distorted" by turbulence. On the right, the corrected versions by JSol'Ex.
December 14, 2025 at 8:06 PM
JSol'Ex 4.4 is out! Adds a number of 3d visualizations, including 3d projection of your images, 4d spectral cube and a volumetric rendering of the solar tomography!

Download it at melix.github.io/astro4j/late...

#JSolEx #solar #science
December 14, 2025 at 4:16 PM
New release of JSol'Ex coming today if everything goes well! A glimpse at what you'll be able to do...
December 14, 2025 at 11:58 AM
Sur cette image inversée, on distingue en foncé les régions actives. Les "nuages" blancs sont des filaments solaires, qui ne sont ni plus ni moins que des protubérances vues "de face".

Le tout traité avec mon soft JSol'Ex 4.3 !
December 3, 2025 at 3:36 PM
Au même moment, une superbe éruption a eu lieu au Nord-Ouest. Une version Doppler de l'image permet de visualiser les vitesses impliquées, énormes (elle s'est déployée sur des centaines de milliers de km en quelques minutes).
December 3, 2025 at 3:36 PM
En ce moment, un groupe d'énormes taches solaires nous fait face. Ce midi, malgré la météo capricieuse, j'ai pu l'imager. C'est stupéfiant à voir : on peut visualiser l'effet du champ magnétique autour de ces taches. C'est un peu l'expérience de la limaille de fer, mais à l'échelle d'une étoile.
December 3, 2025 at 3:36 PM
Sortie de JSol'Ex 4.3.0 avec pas mal d'améliorations (qualité du stacking, performances améliorées, nouvelles fonctions de scripting, ...). J'en ai profité pour ajouter un script qui permet de générer une tomographie solaire.

melix.github.io/astro4j/late...
December 1, 2025 at 10:50 PM
Again nice prominences today on the Sun! Captured with an SHG 700 and processed/stacked using JSol'Ex!

#solar #astrophotography
October 14, 2025 at 8:14 PM
The sun captured in H-alpha late afternoon. Just had a few minutes so it's a stack of 5 images captured with the SHG 700 and entirely processed with JSol'Ex. The Doppler image shows interesting regions with high velocities! The active regions crop even shows Ellerman bombs! #solar #astronomy
August 31, 2025 at 8:33 PM
Right. Basically in my mind, you get gaussians. During the day, gaussian to the peak under ideal condition, and during the year, gaussian at peak month. See actual graphs from here.
August 30, 2025 at 7:32 AM
Same exists in Java
August 28, 2025 at 2:51 PM
La binarisation typique de Trump, la simplification du vocabulaire (les méchants d'un côté, les gentils de l'autre) dans la bouche de Retailleau. Flippant notre époque.
July 25, 2025 at 6:52 AM
Par ailleurs l'argument ne tient même pas la route de manière factuelle, lol.
July 22, 2025 at 9:13 AM
Last image before I pack everything. Helium D3 line.
June 20, 2025 at 8:12 AM
An image of the sun captured from my backyards this morning, under good conditions. All processed with #JSolEx. It also automatically detected a couple of Ellerman Bombs. Science is fun! This afternoon I'm heading to Baron, Oise, in France, for JASON to meet with other solar observers!
June 20, 2025 at 7:06 AM
On est d'accord qu'il y a 20 ans, des "tirs de mortier" on appelait ça des pétards ? Dans ma tête, un mortier c'est ça. Pas vraiment la même chose. A quel moment on a basculé ?
June 8, 2025 at 10:28 AM
April 20, 2025 at 9:43 AM
Fascist attack against the Gnome project. Press release from Solidaires Informatique.
March 20, 2025 at 12:36 PM