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Image: Ahuna Mons on Ceres

This image, based on observations from NASA's Dawn spacecraft, shows the largest mountain on the dwarf planet Ceres.

ESA's Hera asteroid mission borrows eyes of NASA's Dawn

The mission to the smallest asteroid ever explored will employ the same main camera as the mission to the largest asteroids of all. ESA's proposed Hera spacecraft to the Didymos asteroid pair has inherited its main imager ...

Dawn mission to asteroid belt comes to end

NASA's Dawn spacecraft has gone silent, ending a historic mission that studied time capsules from the solar system's earliest chapter.

The coincidence between two overachieving NASA missions

Two vastly different NASA spacecraft are about to run out of fuel: The Kepler spacecraft, which spent nine years in deep space collecting data that detected thousands of planets orbiting stars outside our solar system; and ...

Polar wandering on dwarf planet Ceres revealed

Dwarf planet Ceres experienced an indirect polar reorientation of approximately 36 degrees, a new paper by Planetary Science Institute Senior Scientist Pasquale Tricarico says.

Vesta reveals the childhood of the Solar System

Investigating the earliest and least-known phases of the history of the solar system, when the young sun was still enveloped by a disk of gas and dust in which the planets began to form, is probably one of the most complex ...

Legacy of NASA's dawn, near the end of its mission

NASA's Dawn mission is drawing to a close after 11 years of breaking new ground in planetary science, gathering breathtaking imagery, and performing unprecedented feats of spacecraft engineering.

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Dawn

Dawn is the time that marks the beginning of the twilight before sunrise. It is recognized by the presence of weak sunlight, while the sun itself is still below the horizon. Dawn should not be confused with sunrise, which is the moment when the leading edge of the sun itself appears above the horizon.

The duration of the twilight period between dawn and sunrise varies greatly depending on the observer's latitude, from a few minutes in equatorial regions to many hours in polar regions. Dawn may easily be determined by observing a thread. When the color of a thread can be determined, changing from black to the thread's distinctive color, the 'crack of dawn' has occurred. This same measure of ambient light can be used to determine, conversely, the instant of dusk.

This text uses material from Wikipedia, licensed under CC BY-SA