Do You Know Hubble Space Telescope?
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by: loveshadi
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Word Count: 455
Date: Mon, 8 Feb 2010 Time: 5:55 AM
The Hubble Space Telescope is the largest diameter telescope, which is sent into orbit. The overall length of the Hubble Space Telescope is 12.8 meters. The lens cone diameter of the Hubble Space Telescope is 4.27 meters. And weigh to 11 tons. The Hubble Space Telescope is made up of three main parts: the first main part is the optical body; the second is scientific instrument; and the third is auxiliary system, including two solar paddles with 11.8 meters long and 2.3 meters wide which can provide 2.4KW power, two parabolic antennas communicated with the ground. The forepart of the lens cone is the optical body, and the back of it is a ring module. In the ring module, a unit of scientific instrument is placed on the focal plane of the primary mirror of the Hubble Space Telescope. The solar paddles and antennas project from the center section of the lens cone.
The optical body of the Hubble Space Telescope is the heart of the instrument. Using the Cassegrain-style reflex system, the optical body is made up of two hyperboloidal mirrors: one of the hyperboloidal mirrors is the primary mirror with the diameter of 2.4 meters, and the other is the secondary mirror with the diameter of 0.3 meter which is placed before the primary mirror and is at a distance of nearly 4.5 meters. The rays projected onto the primary mirror firstly reflect onto the secondary mirror, and then ray to the centre bore of the primary mirror through the secondary mirror, next across the centre bore onto the focal plane of the primary mirror and form high-quality images to provide various scientific instruments for processing data accurately, finally the data obtained are sent back to the ground through the data relay satellite system.
Besides the optical body of the Hubble Space Telescope, another main part is the eight scientific instruments placed on the focal plane of the primary mirror: a wide field and planetary camera, a waning light photographic telescope, a waning light astronomical spectrograph, a high resolution spectrograph, a high speed photometer and three precise guidance remote sensors.
These scientific instruments are provided for the operating period of the Hubble Space Telescope during those early years. To make fully use of the latest technology and achievement for developing the Space Telescope, these instruments placed on the focal plane are designed as various combinations and substitute modes. While the Hubble Space Telescope is working, the astronauts of the space shuttle can maintain and replace. Where necessary, also the entire telescope can be carried to the ground by the space shuttle to repair the equipment, then injecting it into orbit. According to design requirements, the lifetime of the Space Telescope is at least 15 years, estimatedly up to several decades in fact.
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