May 20, 1990: Hubble’s first light

NASA released Hubble's first photograph (right) paired with shot of the same area of the sky taken by the ground-based observatory at Las Campanas in Chile, to showcase the comparative sharpness of Hubble's work. Credit: E. Persson (Las Campanas Observatory, Chile)/Observatories of the Carnegie Institution of Washington; Right: NASA, ESA and STScI

After 40+ years of development, design, construction, and delays, the Hubble Space Telescope launched on April 24, 1990, on Space Shuttle Discovery. About a month later, on May 20, its Wide Field and Planetary Camera saw first light, capturing a 30-second exposure around 8.2-magnitude star HD96755, located in open cluster NGC 3532 within southern constellation Carina.

The first photo wasn’t intended to make any scientific discoveries, but was rather for engineering purposes to help focus the telescope. When NASA released the image, it was paired with a matching shot taken from Las Campanas Observatory in Chile. Even with the spherical aberration flaw in Hubble’s primary mirror – which would be discovered in June 1990 and corrected with Servicing Mission 1 in December 1993 – the photo Hubble captured was 50% sharper than the image from Las Campanas. Its position above Earth’s atmosphere frees Hubble from the star-blurring and lack of fine detail that ground-based images can experience.