Why Was Hubble Blurry If Its Mirror Passed the Main Test?

Launched above Earth's atmosphere to escape its blur, the Hubble Space Telescope still fell short of its intended image sharpness. Its primary mirror had passed the main test used to shape it. How could both be true? Follow the investigation from preserved ground-test equipment to the 1993 corrective optics, while the original primary mirror stayed in orbit. Hubble could still do useful science before the repair. Critical Detail's explanations are AI-assisted; narration is fully synthetic. Original illustrations and qualified reconstructions are labelled and are not calibrated optical simulations. This is an independent production; no NASA or ESA endorsement or review is claimed. NASA is not responsible for the accuracy of the AI-generated explanations. ARCHIVAL CREDITS Images are cropped/resized for presentation; the servicing footage is excerpted and muted. Explanatory overlays are Critical Detail's. PC5 star, 14 June 1990: NASA; data supplied by Dr. Jon Holtzman. NASA-TM-103443, Figure 6-1(a). Negative focus-test image, not a repair comparison. https://ntrs.nasa.gov/citations/19910003124 M100 WFPC1/WFPC2 comparison: NASA, STScI. Images: 27 November / 31 December 1993, using different cameras/channels. https://science.nasa.gov/asset/hubble/pict... FOC star before/after COSTAR: NASA, ESA, and the COSTAR Team. Reframed/resized from ESA/Hubble opo9408a, under CC BY 4.0. https://esahubble.org/images/opo9408a/ https://creativecommons.org/licenses/by/4.0/ COSTAR servicing photograph: NASA. https://science.nasa.gov/image-detail/2812... STS-61 footage: NASA's Goddard Space Flight Center. Producer: Katrina Jackson (USRA). Servicing Mission 1 Highlights, GSFC_199312xx_HST_m001. https://svs.gsfc.nasa.gov/13082/ FURTHER SOURCES Hubble's Mirror Flaw: https://science.nasa.gov/mission/hubble/ob... The Camera That Saved Hubble: https://www.jpl.nasa.gov/news/the-camera-t... Why Have a Telescope in Space? https://science.nasa.gov/mission/hubble/ov... 27 June 1990 press-conference archive: https://svs.gsfc.nasa.gov/13083/