In 1990, the field of astronomy was changed forever with the release of Hubble Space Telescope. Although not the first space observatory, its unprecedented resolution and flexibility allowed for the deepest and most detailed images of the universe ever made. The latest image to be released by the mission includes the spiral galaxy NGC 691, which was captured in incredible detail by Hubble’s Wide Range Camera 3 (WFC3).
This galaxy is located about 120 million light-years from Earth in the constellation Aries and is the most important member of a group of gravitationally connected galaxies (known as the NGC 691 galaxy group). The first recorded observations of this galaxy were made by the German-British astronomer William Herschel on November 1
As with other celestial objects, Hubble monitors NGC 691 using a set of filters that allow certain wavelengths of light (from ultraviolet and visible light to infrared light) to reach WFC3. The resulting filtered images are then stained by specialists who select colors that best represent the different wavelengths observed. While ultraviolet light is usually colored in violet and infrared in red, visible light from stars, gas, and dust is shown in white and blue.
These processed images are then combined to create a full-color image that gives an idea of the nature and appearance of celestial objects. In the case of NGC 691, the resulting image shows the beautiful ring structure of the galaxy, the wavy nature of the individual rings, and the intensely bright active galactic nucleus (AGN) – a strong indication of a supermassive black hole (SMBH) in its core.
Decades later, Hubble still provides the world with some of the most breathtaking views of the universe! A number of more advanced observatories will be launched into space very soon, with everyone expected to make some very profound discoveries. Still, none of them can compete with the game-changing character Hubble, which appeared at just the right time and created the foundation on which all future missions will stand.
More information: NASA