Hubble Space Telescope took first image 30 years ago

Hubble still takes interesting pictures of objects from the universe and exactly thirty years ago the space telescope took its first picture. It was not entirely sharp, a shortcoming that was later remedied by a repair in space.

The 30-year-old image in question shows binary star HD96755 in the open star cluster NGC 3532, located in the Carina Nebula. The star cluster is located about 1320 light-years from Earth. Hubble’s photo is shown on the right, and a similar image was taken for comparison with a terrestrial telescope at the Las Campanas Observatory, which is located in the mountains of Chile’s Atacama Desert.

The photo was little more than a first-light test, which focused primarily on whether the light passed through all the optical instruments and hit the detectors. Hubble’s photo was roughly 50 percent sharper than the Las Campanas Observatory photo, according to NASA, which didn’t seem too impressive, given that Hubble had no atmosphere in the way and a shutter speed of 30 seconds. was used, while the astronomers at the US Las Campanas Observatory used only a three-second exposure for their photo.

Gradually, NASA had to admit that the Hubble photo should have been sharper. NASA engineers thought that calibrating the instruments and other actions could improve the situation, but it turned out not to be the case: Hubble’s 2.4m primary mirror showed anomalies that would leave the images slightly out of focus. Therefore, a repair was decided, which was completed in 1993 by spacewalking astronauts. The problem was thus solved. Four other maintenance missions followed between 1997 and 2009.

The top ‘dot’ is HD96755; the one below is an accidental ‘passer-by’. The most recent image from Hubble, showing the rather isolated dwarf galaxy ESO 461-036. There seem to be more galaxies nearby, but they are much further from Earth than the dwarf galaxy.