3 ms·

I always wondered how this happened, given that that the HST was far from a "one-off" product - would love to know if this was an error that affected all of the

I always wondered how this happened, given that that the HST was far from a "one-off" product - would love to know if this was an error that affected all of the KH-11 mirrors up to that point (and went undetected), or if there was something about the Hubble mirror that was different? Unfortunately, that information is probably still classified.

kurthr 8y ago
The focal length of the Hubble was certainly different, but maybe other things too... I'd be surprised if this wasn't a copy/paste error, but maybe it really was some huge miscalculation that nobody caught. There were a lot of KHs (Keyhole) flying long before Hubble so they didn't have unfixed issues and their test fixtures were all set up (and frankly, probably passed Hubble). https://en.wikipedia.org/wiki/KH-11_Kennen https://en.wikipedia.org/wiki/KH-11_Kennen
- baldfat 8y ago
  The mirror was too flat in the middle and there was a slight wave. It was a mechanical issue when the polished the mirror starting in 1979 for over a year. It wasn't launched till 1990.
baldfat 8y ago
They state that the error in the mirror if you enlarged to to the size of the earth would not be any higher than 6 inches. http://www.scienceclarified.com/scitech/Telescopes/Hubble.html http://www.scienceclarified.com/scitech/Telescopes/Hubble.ht... is a great article on it. Since this all happened in my area I was always interested. The fix of the mirror is one of the greatest feats I have ever read. They weren't sure how much could be fixed. It ended up being better than anyone could ever expect.