From: Johns Hopkins University
Posted: Friday, February 18, 2011
Dates Acquired: November 3 and 16, 2010 Instrument: Wide Angle Camera (WAC) and Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS) Larger image.
Of Interest: In 1990, the Voyager 1 spacecraft captured the first portrait of our Solar System as seen from the outside looking in. As a complement to this view, which contained the iconic "pale blue dot" image of Earth, the MESSENGER spacecraft collected this series of images to complete a "family portrait" of our Solar System as seen from the inside looking out.
Comprised of 34 WAC image positions with NAC insets, the majority of this mosaic was obtained on 3 November 2010. However, due to pointing constraints on the spacecraft, the portion of the mosaic near and covering Neptune was acquired a few weeks later on 16 November 2010. All of the planets are visible except for Uranus and Neptune, which at distances of 3.0 and 4.4 billion kilometers were too faint to detect with even the longest camera exposure time of 10 seconds, though their positions are indicated. (The dwarf-planet Pluto, smaller and farther away, would have been even more difficult to observe). Earth's Moon and Jupiter's Galilean satellites (Callisto, Ganymede, Europa, and Io) can be seen in the NAC image insets. Our Solar System's perch on a spiral arm also afforded a beautiful view of a portion of the Milky Way galaxy in the bottom center. Click here to see a graphic showing the positions of the planets at the time this mosaic was acquired.
The curved shape of the mosaic is due to the inclination of MESSENGER's orbit from the ecliptic, the plane in which Earth and the other planets orbit, which means that the cameras must point up to see some planets and down to see others. The images are stretched to make it easier to detect the planets, though this stretch also highlights light scattered off of the planet limbs, and in some cases creates artifacts such as the non-spherical shape of some planets. Around Venus and to some degree Earth, a diffraction pattern that results from light reflecting within the WAC is visible. Each image is a merged product of three calibrated 10-second exposures to reduce scene noise.
The mosaic shown here displays the NAC insets at the full resolution captured by the camera, with the WAC images at reduced resolution. Click here for a full-resolution version of the WAC mosaic (22 MB). Click here to see a NAC image of Jupiter with the Galilean satellites labeled. Click here to read the full news story about what it took to make this Solar System family portrait possible.
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