A Roll-off-the-Roof Observatory is the individual building that houses one or more than one telescopes to protect it from weather (rain, wind, snow, and sunlight). The observatories roof opens and closes, to allow light from celestial objects into telescopes. Astronomers can open the roof and point the telescope "looks" through the open roof, to observe celestial objects.

A Dome Observatory is the individual building that houses one telescope to protect it from the weather (rain, wind, snow, and sunlight). A dome slit opens and closes, to allow light from celestial objects into the telescope. Astronomers can turn the dome and point telescope, so that the telescope "looks" through the slit, to observe celestial objects. Dome rotates 360° to observe every events.