12-18 years

Telescope in the pocket

دشواری: ★

Making your own sky disk

دشواری: ★

Form the armillary sphere to the astrolabe

دشواری: ★

The pyrenean shepherd’s dials

دشواری: ★

Building simple sundials

دشواری: ★

Latitude Gnomon and Guadrant for the Whole Year

دشواری: ★

Making helioscopes with four sticks

دشواری: ★