The Hubble Space Telescope is responsible for a majority of the pretty pictures you find online of stars, galaxies, supernova and other cool things. Hubble was launched on April 24th, 1990 on the space shuttle Discovery. It was placed in a low earth orbit, meaning that it orbits earth like a satellite, and is accessible by human beings. Hubble was supposed to be the best telescope ever launched at the time, but after Hubble transmitted back it's first images, scientists were very worried. Hubble should have sent back crystal clear images, but instead we received fuzzy out of focus images. The problem was that the 2.5m mirror was improperly shaped. It should be a perfectly smooth and specifically curved piece of glass, but during the polishing process, the glass was flattened by an extra 2.2microns (~1/1000 of a millimeter). This tiny error resulted in a huge error in imaging as can be seen below.
Galaxy before corrections Galaxy after Correction
The image on the left was taken with the original mirror, while the image on the right was taken after an adaptive optics system was placed on the telescope to correct for the error. Good thing we placed Hubble in an orbit where we could get to it!
Stay tuned for more information about Hubble, as we lead up to it's 21st Birthday on Sunday!
Fun fact for those who live in Rochester, NY: Hubble's mirror was constructed by Perkin-Elmer company. Kodak was contracted to build the exact same mirror as a backup, in case something went wrong. The stubborn people at Perkin-Elmer refused to let Kodak check their work, and therefore the mirror error was not caught until after Hubble was launched. The mirror Kodak built is now on display at the Smithsonian Institution, and is 100% correct. Yay Kodak!
Image Credit: NASA/HST
Image Credit: NASA/HST
