Hubble's 'First Light'

This "first light" image from Hubble was released in May 1990, to illustrate the telescope's improved resolution when compared to ground-based observatories. On the right is part of the first image taken with the Hubble Space Telescope's Wide Field/Planetary Camera. It is shown with a ground-based picture of the same region of the sky from Las Campanas Observatory in Chile. The Las Campanas picture was taken with a 100-inch telescope and it is typical of high-quality pictures obtained from the ground.

Even accounting for the aberration in Hubble's mirror, the space telescope's image (right) offers more clarity than what was generally possible with ground-based observations (left). Astronauts installed new equipment that successfully addressed the mirror aberration on Hubble during a 1993 mission.
E. Persson (Las Campanas Observatory, Chile)/Observatories of the Carnegie Institution of Washington; Right: NASA, ESA and STScI

The images of the stars in the ground-based picture are fuzzy, and in some cases overlap, because of the smearing effect of Earth's atmosphere. The same stars in the Hubble frame are sharper, as shown by the double star at the top of the image. In this early engineering picture, the Hubble images are roughly 50 percent sharper than the ground-based images.

The first image taken with Hubble was intended to assist in focusing the telescope. The region observed is centered on the 8.2-magnitude star HD96755 in the open cluster NGC 3532, in the southern constellation Carina. Identical small subsections of the Hubble and ground-based images were chosen to highlight the difference in resolution. The field shown is approximately 11-by-14 arcseconds in size and does not contain HD96755.

Cluster NGC 3532 is near the Carina Nebula, a vast star-forming region shown in this Hubble Space Telescope composite image.
NASA, ESA, N. Smith (University of California, Berkeley), the Hubble Heritage Team (STScI/AURA); N. Smith (University of California, Berkeley) and NOAO/AURA/NSF
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