Sol'Ex has already won over a vast community of amateur astronomers around the world. What’s the secret to its success? Simply put, for an affordable price, you receive complete kits (optical and mechanical) that allow you to assemble your own Sol'Ex in just a few hours. Even better, you can print some parts at home using a 3D printer, with clear instructions provided at each step. Once assembled, all you need to do is attach Sol'Ex to the back of any telescope, even a modest one, ensuring that you reduce the intense light from our star (we explain how to do this). You’ll then be ready to capture spectacular images of the star of the day...

View of the solar chromosphere captured by isolating the light from the famous hydrogen alpha (Hα) line, using Sol'Ex mounted on the back of a 100 mm Takahashi telescope, on February 14, 2024. Credit: François Rouvière.

The Sun in color, revealed through different lines of the solar spectrum, captured with Sol'Ex mounted on the back of a 72 mm Sky Watcher 72ED telescope. Credit: Valérie Desnoux.

Solar prominences, on May 19, 2024. Sol'Ex paired with an 80 mm Askar 80PHQ telescope. Credit: Christian Buil.

Doppler image of the chromosphere, where the colors reveal the complex movements of matter, guided by the lines of force of the solar magnetic field. Blue indicates gas moving towards the observer, while red shows gas moving away. Captured with a 128 mm telescope. Credit: Christian Buil.

No need to wait for a solar eclipse or travel to high altitudes; Sol'Ex allows you to observe the solar corona (E) from a lowland site using a small instrument. On the left, the image of the solar corona captured by the "Solar Dynamics Observatory" in ultraviolet on July 24, 2024 (credit: NOAO). On the right, the image taken simultaneously with Sol'Ex, using the green line of ionized iron (Fe XIV). Credit: Olivier Aguerre.

The Sol’Ex instrument is powerful enough to reveal the magnetic field on the Sun's surface. On the left is a magnetogram from the SDO satellite, and on the right, taken at the same time, a magnetogram made with Sol’Ex by observing the Zeeman effect on the Fe I 6302 Å spectral line. The black and white colors indicate the magnetic field's intensity according to its polarity. Credit: Olivier Aguerre.

Sol'Ex democratizes the use of the spectroheliograph, a powerful observation tool that has until now been primarily reserved for professional observatories.

Easy to assemble and use, the Sol'Ex project comes with extensive documentation to guide you at every step. You will find video tutorials on YouTube, numerous articles on websites, as well as an active forum and a mailing list to engage with other enthusiasts.

The principle and implementation illustrated by Jérôme Bastardie for Sol'Ex. See Espace-Infini

Sol'Ex also includes an educational component, ideal for presentations to clubs, schools, and the general public. See for example: phaenovum Centre de recherche étudiant, here and chere,  or  Science à l’Ecole (CLEA).

But that's not all! Sol'Ex is designed to easily transform into a powerful astronomical spectrograph, becoming Star'Ex – the "Star Explorer." Check the Stars section of this site to learn more. With Star'Ex, the spectra of stars, nebulae, galaxies, and quasars are within your reach!

Star’Ex spectrum of comète 12P/Pons-Brooks, April 11, 2024.

Star'Ex spectrum of the aurora borealis on May 10, 2024, observed from southern France.

Sol'Ex/Star'Ex also includes a suite of software for processing data: INTI for Sol’Ex, specINTI for Star’Ex.

Enjoy discovering Sol'Ex and Star'Ex!

Project prtésentation (ProAm, SF2A, 2021)