12-18 years

Telescope in the pocket

कठिनाई: ★

Making your own sky disk

कठिनाई: ★

Form the armillary sphere to the astrolabe

कठिनाई: ★

The pyrenean shepherd’s dials

कठिनाई: ★

Building simple sundials

कठिनाई: ★

Latitude Gnomon and Guadrant for the Whole Year

कठिनाई: ★

Making helioscopes with four sticks

कठिनाई: ★