Optical kit for Sol’Ex spectroheliograph

Please note: this kit contains only the optical elements (see Composition tab). You’ll also need to source the 3D-printed parts and other components (cameras, accessories, etc.).

With Sol’Ex (Solar Explorer), make incredible images of the Sun, as if you had a particularly narrow filter (typically 0.3 Ångström), much narrower than any commercially available filter, which will produce high-contrast views of the chromosphere. You can also choose the wavelength of your image (H-alpha, H-beta, sodium, helium, calcium… the entire visible range is accessible).

Sol’Ex project:

Sol’Ex is a small self-built instrument with 3D-printed parts. The project was proposed and led by Christian Buil. The Sol’Ex project website gives all the practical details for installation and use in the field. Sol’Ex should be mounted on a small telescope (with a focal length of 450mm max), to see the whole Sun in a single image, but a longer focal length is possible and will give more detailed images of portions of the disk. This project includes automatic image processing software: the result appears on the screen in just a few clicks. Sol’Ex works on the principle of a spectroheliograph: the image is built up line by line by scanning the image of the Sun (it’s the same principle as a photocopier, except that in this case the copy is an image of the Sun).

The Sol’Ex optical kit offered by Shelyak includes all the optical components needed to build the instrument: slit, grating, lenses, etc. You’ll need to source the parts independently in 3D printing, or build them yourself if you have a printer (STL files available on the Sol’Ex website). Find out more about the Sol’Ex & Star’Ex project in this article.

Going further… :

Once you’ve familiarized yourself with Sol’Ex, you’ll understand that this instrument can also be turned towards (other) stars. Sol’Ex was then transformed into Star’Ex (Star Explorer), a small Very High Resolution (VHR) spectrograph. A few additional optical elements are needed to transform a Sol’Ex into a Star’Ex. This is the purpose of the complementary optical kit (ES0030 – Star’Ex HR complementary kit). You can also opt now for the Star’Ex High Resolution optical kit, which contains all the components needed to make a Sol’Ex, then transform it into a Star’Ex HR.

• Resolution at 650 nm with 10 micron slit width: 0.03 nm
• Wavelength range: 400 nm – 700 nm
• Internal reduction ratio: 125:80
• 10µm slit for maximum resolution (Sol’Ex), or 15, 19, 23 or 35µm slit depending on your telescope (Star’Ex)

These technical specifications apply to the Sol’Ex instrument once assembled (and not to the optical kit).

Sol’Ex optical kit:

• [OP0176] Doublet colimateur d’un diamètre de 25,4mm et d’une focale de 80mm
• [OP0181] Doublet objectif d’un diamètre de 25,4mm et d’une focale de 125mm
• [OP0177] 25 x 25mm 2400 tr/mm holographic grating
• [SE0253] A reflective slit 10 µm wide and 4.5 mm long on support

Summary table of the various kits

Articles about the Sol’Ex & Star’Ex project

Sol’Ex project website

• With the Sol’Ex, you can not only take magnificent images of the sun, but also study sunspots and protuberances on the sun’s surface, tracking their evolution over time.
• The resolution is such that you can even measure movements on the Sun’s surface (and its rotation) using the Doppler effect.
• The fact of assembling and adjusting the instrument yourself allows you to fully understand its optical operation; It’s simple and very educational. So much so, in fact, that Sol’Ex has its place in schools and universities, as well as in astronomy and popular science associations.