Uploaded March 2026 | Updated September 2026, 3 weeks ago
#VoxxedDaysCERN26
The Sol'Ex (aka "Solar Explorer") is a DIY instrument invented by Christian Buil, which enables observations of the sun in different wavelengths which has revolutionized full solar disk imaging in amateur astrophotography. It is a kind of so-called "spectroheliograph", an instrument which was invented back in 1890. With modern technologies like CMOS cameras, we can now build cheap devices which makes observing the sun accessible to everyone. What is interesting, however, is that such a device doesn't directly produce an image: software processing is mandatory, because we need to reconstruct an image from a video which only contains images of a portion of the light spectrum.
With Sol'Ex, this processing was done with INTI, a program written in Python by Valérie Desnoux. As an amateur astronomer, I have used software for astronomy image processing, but as a developer, I hadn't implemented anything myself yet. Therefore I challenged myself and started a project in order to write my own software, called JSol'Ex, in Java. This project started as an experiment, so that I understand the "science" behind the image reconstruction, and see if I was still capable, after 20+ years of programming, to implement algorithms based on research papers. In this session, I will explain what I have learnt: the principles of capturing images with the Sol'Ex instrument, how images are reconstructed, but also the various features I have added to JSol'Ex which make it now a reference in its domain.
#VoxxedDaysCERN26
The Sol'Ex (aka "Solar Explorer") is a DIY instrument invented by Christian Buil, which enables observations of the sun in different wavelengths which has revolutionized full solar disk imaging in amateur astrophotography. It is a kind of so-called "spectroheliograph", an instrument which was invented back in 1890. With modern technologies like CMOS cameras, we can now build cheap devices which makes observing the sun accessible to everyone. What is interesting, however, is that such a device doesn't directly produce an image: software processing is mandatory, because we need to reconstruct an image from a video which only contains images of a portion of the light spectrum.
With Sol'Ex, this processing was done with INTI, a program written in Python by Valérie Desnoux. As an amateur astronomer, I have used software for astronomy image processing, but as a developer, I hadn't implemented anything myself yet. Therefore I challenged myself and started a project in order to write my own software, called JSol'Ex, in Java. This project started as an experiment, so that I understand the "science" behind the image reconstruction, and see if I was still capable, after 20+ years of programming, to implement algorithms based on research papers. In this session, I will explain what I have learnt: the principles of capturing images with the Sol'Ex instrument, how images are reconstructed, but also the various features I have added to JSol'Ex which make it now a reference in its domain.
