https://www.thisdayinaviation.com/24-april-1990-123351-utc-t-minus-zero/ Important Dates in Aviation History Thu, 24 Apr 2025 16:43:35 +0000 hourly 1 https://www.thisdayinaviation.com/24-april-1990-123351-utc-t-minus-zero/#comment-24163 Mon, 27 Apr 2020 03:09:53 +0000 http://www.thisdayinaviation.com/?p=18731#comment-24163 To the researcher’s dismay, the first Images fell far short of expectations . It turns out the mirror was made ‘perfectly’ wrong. A misalignment of the optical alignment measuring rig resulted in a slight error in the grinding of the primary mirror introducing spherical aberrations. Fortunately, it was possible to redesign some downstream optics by essentially inverting the error to correct the aberrations. Modified optics were installed during the first Hubble servicing mission in December 1993 (STS-61). This corrected the compromised optics and Hubble performance was now producing the amazing images we have come to know. Future instrument upgrades would have to include corrective optics.

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