Hoạt động: Vũ trụ

Orion

Sự khó khăn: ★ ★

Ranking the brightest stars of a constellation

Sự khó khăn: ★ ★

Making a constellation slide

Sự khó khăn: ★ ★

Brilliant stars on the screen by overhead projector

Sự khó khăn: ★

An estimate of the number of stars visible to photographs

Sự khó khăn: ★ ★