One peek into a small part of the sky, one giant leap back in time. This small patch of sky represents less than 1/100,000,000th of the volume of the Universe, but reveals nearly 1,000 galaxies that had never been seen before. This small fraction of the original Hubble Deep Field image is a huge part of how we learned what our Universe looks like. (R. WILLIAMS (STSCI), THE HUBBLE DEEP FIELD TEAM AND NASA/ESA)

The Most Important Image Ever Taken By NASA’s Hubble Space Telescope

The original Hubble Deep Field truly showed us what the Universe looks like.

Later this month, the Hubble Space Telescope will celebrate its 30th anniversary.

This photo of the Hubble Space telescope being deployed, on April 25. 1990, was taken by the IMAX Cargo Bay Camera (ICBC) mounted aboard the space shuttle Discovery. It has been operational for 30 years, and has not been serviced since 2009. With a 2.4-meter diameter mirror, it gathers as much light in 1 minute as a 160-mm (6.3") telescope would require 3 hours and 45 minutes to gather. (NASA/SMITHSONIAN INSTITUTION/LOCKHEED CORPORATION)

More than any other observatory in history, Hubble revealed what the Universe looks like.

Looking back from the present day, we can see a ‘pencil beam’ view of the distant Universe. But a huge number of galaxies are still undiscovered, owing to the limitations of how we’re capable of looking. Hubble has taken us remarkably far, but there’s still farther to go. (NASA / STSCI / A. FEILD)

When it was first launched, a problem with its mirror’s optics produced only flawed images.

The before-and-after difference between Hubble’s original view (left) with the mirror flaws, and the corrected images (right) after the proper optics were applied. (NASA / STSCI)

In late 1993, new flaw-correcting equipment was installed, along with an improved camera: WFPC2.

The Wide Field and Planetary Camera 2 (WFPC2) was Hubble’s workhorse camera for many years. It recorded images through a selection of 48 colour filters covering a spectral range from far-ultraviolet to visible and near-infrared wavelengths. The ‘heart’ of WFPC2 consisted of an L-shaped trio of wide-field sensors and a smaller, high resolution (Planetary) Camera placed at the square’s remaining corner. (NASA)