The Hubble Telescope
Conceptualized in 1946 and launched in 1990, the Hubble telescope orbits the Earth and sends pictures back that aren't blurred by background light or the atmosphere. The telescope was named after Edwin Hubble who made a great scientific breakthrough when he found that the universe was expanding. After the Hubble was launched into space, one of the main mirrors was causing aberrations in the pictures being sent back to Earth. In 1993, a servicing mission was deemed necessary and they returned the telescope to its former capabilities.
Currently in 2007, several of the Hubble's turning gyroscopes have failed, and its main camera stopped working. There is a planned service mission scheduled for 2008 which will hopefully allow the telescope to function until 2013. After that, a new telescope will be launched to take its place. The James Webb Space Telescope will be superior to the Hubble in many ways, but will only record in infrared.
Challenges were also part of the telescope's creation. It would have to able to withstand direct passes by the sun and behind the earth. Temperatures in these areas were either extremely hot or extremely cold. The scientists finally came up with a multi-layer shroud to keep the temperature within the telescope stable at all times.
The mirrors were another problem. They were polished and ground from the beginning of 1979 until May of 1981. Using low expansion glass, they kept the mirror's weight at a minimum. The mirror was finished by the end of 1981, and they added a reflective coat of Aluminum and a protective coat of Magnesium Fluoride.
The Hubble has given us pictures of comets, the planets, established the presence of black holes, and other stars and galaxies nearby. To view the wondrous images, go to http://archive.stsci.edu/hst and click on gallery. You will find some of the most incredible pictures you have ever seen.
Telescopes
Factors To Consider When Purchasing A Telescope
Historical Timeline For Telescopes
Viewing Deep Sky Objects And Comets
Telescopes
... clean and in line. If you grind the mirror wrong, it will distort your images. Since the scopes will have a huge light focusing ability, you will be able to view deep sky objects as well as take pictures of what you are seeing. There are many designs that you can choose from for your telescope, but the ...
... mount uses two axes that are lined up with the poles to keep track of the motion an object takes across the sky. The axes can be Right Ascension, Polar, or Declination. Instead of moving up and down on its axes like the Alt-Azimuth, this particular mount is tilted toward the Earth's axis of rotation. ...
... best to start with because they are easy to find. Then after that, the sky, quite literally, is the limit. With a special filter, you can see the sun and count sunspots. Observe the milky way or the moon. The moon has many large craters and you may see rays coming out from them. These are from when a ...
... helpful in viewing objects. One is it must have a well-aligned and intact mirror. It must have at least one eyepiece, two are better. The scope must have a mount that firm and secure. Unstable mountings is a problem for beginner astronomers. You should also have a finder that rides beside the main telescope. ...
... the yardstick making sure one lens is out on the side. Place the flashlight on a stand about twelve feet away. Shine the light at the lens that is sticking out. Place the thin sheet of paper on the side across from the flashlight. Walk away from the paper until you see a small picture of the flashlight ...