I would like to present my design for a handheld spectroscope.

This spectroscope utilizes a diffraction grating with 1000 lines/mm. The grating material should be cut to approximately 25mm x 25 mm. The slit is 0.5 mm wide, which results in a clear and distinct spectrum.

Since some 3D printers have a tendency to produce 'elephant's foot', I have included a 0.75mm version of the slit. This should guarantee that the resulting aperture remains sufficiently wide.

The grating is angled at 30° to ensure all lines of the visible spectrum are sharply focused. The photo below provides an idea of the resulting spectrum, which was captured using a compact fluorescent lamp (CFL) as the light source. In reality, the spectrum appears slightly better when viewed with the naked eye.

The body of the spectroscope is constructed from a 40 mm (DN 40) HT plastic pipe sourced from a hardware store, cut to a length 25 cm. The grating foil is glued into place, and the end caps are simply pushed onto the pipe. Any filament can be used for the 3D-printed parts, but it is recommended to use black filament to minimize internal reflections.

Links to Materials Used: Grating (eBay): https://ebay.us/m/mgCztV HT 40 Pipe (OBI): https://www.obi.de/p/7436819/marley-ht-rohr-mit-steckmuffe-dn-40-grau-500-mm

Never look directly at the sun with the spectroscope!