1. (noun) a building housing an instrument for projecting the positions of the planets onto a domed ceiling

• building
• edifice

2. (noun) an optical device for projecting images of celestial bodies and other astronomical phenomena onto the inner surface of a hemispherical dome

• optical device

3. (noun) an apparatus or model for representing the solar systems

• model
• simulation

1. (noun) an apparatus or model for representing the solar systems

• orrery