A NASA camera aboard the Deep Space Climate Observatory (DSCOVR) satellite snapped a view of the moon as it moved in front of Earth recently.
The images were captured by NASA’s Earth Polychromatic Imaging Camera (EPIC), a four-megapixel CCD camera and telescope on the DSCOVR satellite orbiting 1 million miles from Earth. From its position between the sun and Earth, DSCOVR conducts its primary mission of real-time solar wind monitoring for the National Oceanic and Atmospheric Administration (NOAA).
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. The EPIC camera is providing a series of Earth images allowing study of daily variations over the entire globe.
These images were taken between July 4 and July 5, showing the moon moving over the Indian and Pacific oceans. The North Pole is at the top of the images. EPIC captured a similar event last year.
EPIC’s “natural color” images of Earth are generated by combining three separate monochrome exposures taken by the camera in quick succession. EPIC takes a series of 10 images using different narrowband spectral filters — from ultraviolet to near infrared — to produce a variety of science products. The red, green and blue channel images are used in these color images.
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. Because the moon has moved in relation to Earth between the time the first (red) and last (green) exposures were made, a thin green offset appears on the right side of the moon when the three exposures are combined. This natural lunar movement also produces a slight red and blue offset on the left side of the moon in these unaltered images.
DSCOVR is a partnership between NASA, NOAA and the U.S. Air Force with the primary objective of maintaining the nation’s real-time solar wind monitoring capabilities, which are critical to the accuracy and lead time of space weather alerts and forecasts from NOAA.