What makes a planetarium different to other theatres is the dome or rounded ceiling, which we can project images onto. The Melbourne Planetarium has a 16 metre dome that surrounds the audience on all sides, providing an immersive experience like no other. The dome is made out of aluminium sheeting and is perforated so that sound can travel up and out of the theatre. Sound carries strangely in this environment and people used to working in planetariums know that there "are no secrets in a dome". This is because sound travels around the curved surface so that even a whisper can be heard quite clearly by a person located on the opposite side of the theatre. If you stand right in the centre of the dome and speak all the sound bounces directly down on top of you - quite a disconcerting experience.
Melbourne Planetarium has unidirectional seating, which means that all seats face in the same direction. However, because the planetarium screen is the dome above there is no disadvantage by having a tall person sit in front of you. In fact to make the experience as comfortable as possible the seats recline, expanding your view of the dome and creating the feeling that you are literally lying underneath a starry sky.
Projectors and Other Hardware
Everything you see on the dome is projected by six video projectors, positioned around the rim or base of the dome. Five of these projectors each cover one wedge on the dome and the sixth covers the zenith (the point overhead). These six images knit together seamlessly to cover the entire dome in movement and colour.
The Heart of the System
The Melbourne Planetarium experience is controlled by two specialist computer software packages, Sky-Skan's DigitalSky and SkyVision. DigitalSky uses massive amounts of processing power to generate every image "on-the-fly". With this system we can reproduce the night sky in incredible detail and true-to-life colour. DigitalSky can be programmed to provide night sky vistas, 3D images and close ups of planets. To compliment the real-time system, SkyVision uses pre-recorded information stored on the computer's hard-drive to play back sequences or entire planetarium shows. SkyVision, combined with the Planetarium surrounds, creates a level of audience immersion that even large format flat screen theaters cannot provide.
The Melbourne Planetarium has been fitted with 6-channel stereo surround sound. An array of eleven JBL studio monitors is suspended above the dome complimented by a large array of sub-woofers built into the front of the theatre.