STS-31, the #SpaceShuttle mission that deployed the #Hubble Space Telescope, launched #OTD in 1990: April 24.
However, the astronauts didn't deploy the observatory until April 25.
My view -- which is not held by the good folks at STScI -- is that Hubble's birthday is thus the 25th; I liken it to April 24th is when Hubble's parents drove to the hospital / went into labor, but the 25th is when it was born. #Astrodon#HistoryOfAstronomy#NASA
