Friday, April 24, 2015

Hubble Space Telescope at 25

This photograph, taken by the Hubble Space Telescope, was recently released by NASA, for the 25th anniversary of the telescope's years in orbit of the Earth. The bright lights in the center of the photo is actually a cluster of about 3,000 stars that was discovered by Bengt Westerlund, a Swedish astronomer, in the 1960s. That cluster is now known as Wusterlund 2 and is located about 20,000 light years away from Earth and measures between six and 13 light years from end to end. The 2-million year old cluster is part of the constellation Carina and located in a section of space called Gum 29. Aside from the stars, which are relatively young in terms of space, the blue/green hues are oxygen and the red is hydrogen. (Image Sources: NASA, )

By Glenn A. Walsh
Reporting for SpaceWatchtower

Twenty-five years ago today (April 24), the Hubble Space Telescope was launched from Cape Canaveral, and since then has given us an unprecedented look into our universe.

Many telescopes and observatories have been constructed all over the Earth, over the last few centuries. However, they all had one and the same problem. Earth's atmosphere limited the distance into the cosmos, and the details of celestial objects, that could be seen by these telescopes, due to blurring of the images seen.

Scientists realized this as early as 1923, when it was first suggested that a telescope in outer space would not be so limited as those on the Earth. However, it was not until 1990 April 24 that the Hubble Space Telescope was launched to provide a new look on the universe, after several delays including the tragic loss of Space Shuttle Challenger.

But once in orbit, a new problem became obvious. The Hubble Space Telescope had, what some people termed, a telescope's verson of being near-sighted. Actually, the pictures taken by Hubble were not much better than those taken from Earth-bound telescopes, because there had been a minute error in how the telescope's mirror had been ground. The mirror's curvature had been off by only 2.2 microns (1/50th as thick as a piece of paper). However, this was enough to threaten the mission of this telescope.

Fortunately, the Hubble Space Telescope was designed to accommodate servicing missions by astronauts, particularly to install upgraded equipment. The first servicing mission by Space Shuttle Endeavour astronauts, in December of 1993, was used to install corrective optics (smaller mirrors to correct for the error in the large mirror) in the telescope.

This was one of the most complex Space Shuttle missions, requiring five days of astronaut space walks, to complete the work. On 1994 January 13, NASA declared the mission a complete success, displaying new stellar photographs which were much crisper and sharper. This was also a major success for astronomers, who could now do more in-depth research with an extremely capable telescope.

Four more servicing missions, to the Hubble Space Telescope, were conducted from the Space Shuttle. As technology improved over the years, new equipment was added to the telescope, to improve its capabilities. In fact, the Space Shuttle was kept flying just a little longer so an extra trip to the Hubble Space Telescope could be accommodated.

"Even the most optimistic person to whom you could have spoken back in 1990 couldn’t have predicted the degree to which Hubble would re-write our astrophysics and planetary science textbooks," said Charlie Bolden, NASA Administrator and pilot of the mission that brought Hubble into orbit. "A quarter century later, Hubble has fundamentally changed human understanding of the universe and our place in it."

More on the Hubble Space Telescope --
Link 1 >>>
Link 2 >>>

Photographic Slide Show of Hubble Space Telescope Images:
Link >>>

Photographic Gallery of Hubble Space Telescope Images:
Link >>>

Wereschagin, Mike. "NASA head tells Pitt grads their generation will 'walk the face of Mars'."
Pittsburgh Tribune-Review 2015 April 26.
Astronaut Charles Bolden, now NASA Administrator, was part of the Space Shuttle Discovery crew which deployed the Hubble Space Telescope.
Link >>>

Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss.

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