The Melbourne Planetarium is the first in the Southern Hemisphere to use the Digistar II - a computer graphics system especially designed for planetariums. Combined with the domed ceiling, reclining chairs, an array of slide and video projectors, and stereo surround sound, a visit to the Planetarium is an experience unlike any other.
Discover the features of the Planetarium and the changes from the H.V. McKay Planetarium that served the Victorian people for over 30 years.
Planetariums are unique because of their dome or rounded ceiling, curved to represent the night sky. The dome is made out of aluminium sheeting and is perforated so that sound can travel up and out of the theatre. The H.V. McKay Planetarium's 10 metre dome was made of solid fibreglass. Not only did this trap the sound but it lead to strange noise effects. Since sound travelled around the curved surface even a whisper could be heard quite clearly by a person located on the opposite side of the theatre.
130 seats, unidirectional
Unlike the H.V. McKay planetarium where the seats were arranged in a circle with everyone facing the star projector in the centre of the dome, the seats in the Melbourne Planetarium all face in the same direction. This creates a central focus for the audience. The seats all recline and come from New Zealand.
The Star Projector(Digistar II)
The biggest change between the two planetariums is the star projector. The original GOTO optical star projector is on display in the foyer of the Melbourne Planetarium. At each end of the optical projector a lamp shone through 15 lenses. Attached to each lens was a shell on which the position of the stars had been etched. Light streamed out through the shells to create very crisp star images. However optical star projectors are limited because they are two-dimensional. The information they contain is restricted to the current relative positions of the stars.
The Melbourne Planetarium is the first in the Southern Hemisphere to be fitted with the Digistar II, the latest version of the digital star projector. Development of the Digistar began in the early 1980's by an American company, Evans & Sutherland, who specialise in computer graphics and simulations. The Digistar is a purpose built computer graphics system that can be likened to a star computer with a screen that lies horizontally and points up towards the domed ceiling. A large fish-eye lens on top of the screen magnifies the computer display and focuses the images of the stars.
The Digistar II contains a database of the 3-D positions of 9 094 stars in the Milky Way. This includes all of the known stars with magnitudes 7.96 or brighter (6 times fainter than the eye can see) and out to about 650 light years. The 3-D capability of the Digistar means that it can create the sensation of travelling through our Galaxy, by accurately depicting the shift in position of the stars as if we were approaching them.
The stars in our sky also move relative to each other. Some faster than others but even the fastest star (Barnard's Star) takes 200 years to travel the width of the Full Moon. Therefore we don't see any real change in the positions of the stars within our own lifetime but over 10 000's of years the movement of the stars can cause the constellations to change shape. The Digistar can be used to travel backwards (or forwards) in time, to see how the stars were arranged in the sky up to a million years in the past (or the future).
In fact, the Digistar can draw any image consisting of dots and lines and project it onto the dome in three-dimensions. For example, the Digistar is an impressive tool for three-dimensional modelling of molecules, such as projecting the 3-D structure of a DNA sequence.
Sitting around the rim of the dome are 23 pairs of slide projectors. The slide projectors are linked in pairs with one slide projector positioned above another to form a single dissolve slide projector. This allows for unobtrusive changes of images where one image fades out slowly (or dissolves) to be replaced by a new image. Each set of dissolve slide projectors has a specific role.
The sense of being in a new location is conveyed by the panorama images that show a picture of the full 360° horizon. These images are created by 12 sets of dissolve slide projectors equally spaced around the dome projecting horizon scenes that join seamlessly.
All-Sky The new planetarium has the ability to display a single picture that covers the entire dome. To create this picture 6 sets of dissolve slide projectors are required with each projector creating a 'cone-like' picture on the dome.
Single slides Five extra sets of dissolve slide projectors are set up facing the front of the dome for projection of single pictures.
A slide projector fitted with a large zoom lens and attached to a motorised mirror is used to create the effect of seeing an object, such as a planet, appear to approach and move away. While any motion picture or animation is displayed on the dome using 3 video projectors; one that is fixed and points towards the front and two that are motorised so they can project onto different parts of the dome.
The Melbourne Planetarium has been fitted with 6-channel stereo surround sound. An array of 11 JBL studio monitors is suspended above the dome complimented by a large array of sub-woofers built into the front of the theatre.
The planetarium also has special effects projectors to produce:
-:- sunrise / sunset / colour change of the dome
-:- bolides (fireball meteors)
-:- lightning, snow and clouds
The Melbourne Planetarium is a wonderful experience for children and adults.
❊ What's On ❊
❊ Address & Contact ❊
⊜ 2 Booker St Spotswood | Map
✆ +61 3 9392 4800
❊ Web Links ❊
→ Melbourne Planetarium
❊ Also See... ❊
→ H V McKay Planetarium
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