This is an easily 3D print-able spectroscope that uses a lens, mirror, and 1000 line/mm diffraction grating. It will allow for reasonable detail in seeing the spectra of everyday objects. It has an adjustable slit to allow for the right balance of brightness vs. detail. can be focused on both distant and close objects. sunlight is a good resolution test as the hydrogen absorption lines will be visible if properly focused.

The lens is optional, but a 25mm round convex lens with a focal length between 25-50mm seems to give the best result. The mirror is a 120mm x 25mm piece of a front-silvered mirror cut to size