An old astronomical instrument formed of two cones, on whose surface the constellations were delineated.

What is astroscope used for?

noun. Originally: any of several instruments for assisting an observer in identifying stars and constellations, specifically one consisting of a pair of inscribed cones. In recent use: an instrument for observing stars; an astronomical telescope.

Is Don't a single word?

A contraction is a word made by shortening and combining two words. Words like can't (can + not), don't (do + not), and I've (I + have) are all contractions. People use contractions in both speaking and writing.