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Revealed: The 'dark side' of Moon

August 06, 2015 13:24 IST

A NASA satellite, orbiting one million miles away, has captured stunning images of the Moon passing the Earth's sunlit side, which show the 'dark side' of the lunar body that is never visible from our planet.

A NASA camera aboard the Deep Space Climate Observatory satellite captured a unique view of the Moon as it moved in front of the sunlit side of Earth last month.

The series of test images shows the fully illuminated "dark side" of the Moon that is never visible from Earth, NASA said.

The images were captured by NASA's Earth Polychromatic Imaging Camera, a four megapixel CCD camera and telescope on the DSCOVR satellite orbiting one million miles from Earth.

EPIC maintains a constant view of the fully illuminated Earth as it rotates, providing scientific observations of ozone, vegetation, cloud height and aerosols in the atmosphere.

Once EPIC begins regular observations next month, the camera will provide a series of Earth images allowing study of daily variations over the entire globe, NASA said.

About twice a year the camera will capture the Moon and Earth together as the orbit of DSCOVR crosses the orbital plane of the Moon.

The latest images were taken on July 16, showing the Moon moving over the Pacific Ocean near North America.

The North Pole is in the upper left corner of the image, reflecting the orbital tilt of Earth from the vantage point of the spacecraft.

The far side of the Moon was not seen until 1959 when the Soviet Luna 3 spacecraft returned the first images. Since then, several NASA missions have imaged the lunar far side in great detail.

The same side of the Moon always faces an Earthbound observer because the Moon is tidally locked to Earth. That means its orbital period is the same as its rotation around its axis.

EPIC's "natural colour" images of Earth are generated by combining three separate monochrome exposures taken by the camera in quick succession.

Combining three images taken about 30 seconds apart as the Moon moves produces a slight but noticeable camera artifact on the right side of the Moon.

The lunar far side lacks the large, dark, basaltic plains, or maria, that are so prominent on the Earth-facing side.

The image, above, shows the far side of the moon, illuminated by the sun, as it crosses between the DSCOVR spacecraft's Earth Polychromatic Imaging Camera camera and telescope, and the Earth -- one million miles away. Photograph: NASA/NOAA 

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