January 2008 Sky from the Keeble Observatory What would you do
if you had one last chance to renovate and refurbish your
favorite car, knowing that you would only be able to drive it
for another 20,000 miles? When it was launched in April 1990,
the Hubble Space Telescope was hailed as the greatest
instrumental advance in astronomy since Galileo first looked up
through his telescope. Excitement turned quickly to dismay, as
preliminary tests revealed that its 2.6 meter primary mirror was
flawed. Ground with high precision to the wrong shape, (the edge
of the mirror was too high relative to its center by
approximately the thickness of a human hair) Hubble began to
look like a technological embarrassment. The cause of the error
was a testing “jig” which had been assembled with one component
out of place. Knowing that, and actually having the device
available, it became possible to design corrective optics, which
were installed by shuttle astronauts in 1993. Since then, the
telescope has returned spectacular image