What is a Planetarium?
Although a planetarium and an observatory both involve domes and both involve astronomy, they are not the same thing. A planetarium involves the projection of astronomical images such as stars, planets, the moon, the sun and other objects onto the inner surface of a dome, in order to visualize what the night sky looks like for the purpose of educational instruction. A planetarium can be used in the daytime to visualize the night sky, and can present a visualization of the sky to city residents that is otherwise only available from dark viewing locations located far from brightly lit urban areas. Modern planetariums can also do much more than this. An observatory houses a telescope that is used to view, photograph or take digital images of astronomical objects in the sky. Traditionally telescopes operated only at visible wavelengths, that is, at wavelengths of electromagnetic radiation that are visible to the human eye. In the last half of the twentieth century astronomers started build
A planetarium is a facility with a specialized theater in which representations of the solar system, galaxy, or universe can be projected. With the use of a hemispheric screen and a specialized projector, a planetarium can surround viewers with a glimpse into the night sky. Planetariums of varying sizes can be found all over the world, and they are popular destinations for people of all ages. Chances are high that there is a planetarium somewhere near you; to find one, you can search for “planetarium” and your area in your favorite search engine. The roots of the planetarium are quite ancient, and the term was actually originally used to refer to a model of various celestial bodies, also known as an orrery. People used a wide variety of techniques to create projections and representations of the night sky for study and education, but the Zeiss firm is usually credited with the development of the modern planetarium, in the early 1920s. Zeiss developed the projector technology necessary
The main feature at any planetarium are the astronomical shows presented in the “Star-theatre,” so special attention has to be paid to the theatre s design. At the Montréal Planetarium, our Star-Theatre seats 385 people in a series of concentric circles. Above the theatre there sits a hemispherical dome, 20 metres in diameter. In all, 1309 thin aluminum plaques, each containing 2500 tiny perforations, cover the inside of the dome s tubular support structure. The perforations reduce weight and undesirable echos, by allowing sound to pass right through the dome. This means loudspeakers and even lighting effects can be placed behind the dome out of public view. The Planetarium main piece of equipment is the Zeiss projector which sits at the centre of the theatre. The replacement cost of this 2.5-ton machine would be about 3 million dollars (Canadian). Apart from the Zeiss star projector, there are 70 slide projectors, and 150 projectors for special effects. Most of these were designed and
(old discussion, in considerable need of updating) (1) The planetarium dome: The most obvious feature of a planetarium is the dome, usually but not always hemispherical, which serves as a projection screen for the planetarium projector and auxiliary devices. A thirty-five foot diameter hemispherical dome was installed in the planetarium classroom near the end of the D building remodel, several years ago. The base of the dome sits about 8 feet above the classroom floor, and with a radius of nearly 18 feet, the top of the dome extends more than 25 feet above the floor. To reduce the size of the concrete box which holds the planetarium, a truncated pyramid was centered above the room, and the dome and its support extend into that pyramid. In addition, a patinated copper dome, complete with lightning rod, was added to the top of the pyramid, albeit only as an advertisement of the location of the planetarium, as the planetarium dome does not extend into the exterior dome. The dome and cove
A planetarium is a domed theater where simulations of the night sky and images of stars, planets and other celestial objects are projected on screens above and around the audience. The newest generation of planetariums use fully digital projection systems, such as the Soref Planetarium’s Digistar 3 full-dome video technology. This gives planetariums great flexibility in showing not only the night sky, but any other image they wish.
