On Wed, Apr 6, 2011 at 10:20 AM, Bruce Walker <[email protected]> wrote:
> And we think Pentax QA is bad. :-) The root cause of the problem was that an apparatus used to test the mirror was incorrectly assembled. The HST primary was then precisely ground to exactly the wrong figure. http://en.wikipedia.org/wiki/Hubble_Space_Telescope#Flawed_mirror > So how did they fix that? Send up a new mirror? They replaced one of the instruments with a corrective optics package called COSTAR, that sits in the optical path and corrects the problem. It's basically the opposite of Larry's idea of a teleconverter that introduces spherical aberration. It's fortunate that the HST was designed for on-orbiting servicing and instrument upgrades. Many newer space telescopes are sent to orbits where they cannot be reached my manned craft. -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
