he Moon, tiny Earth and the vastness of space,as seen by the Lunar Reconnaissance Orbiter Wide Angle Camera (WAC). Credit: NASA/GSFC/Arizona State University.
That’s Earth. That’s us. Way off in the distance as a fairly small, blue and swirly white sphere. This is the newest so-called “Earthrise” image, and it was taken on February 1, 2014 by the Lunar Reconnaissance Orbiter.
“LRO experiences twelve earthrises every day, however LROC is almost always busy imaging the lunar surface so only rarely does an opportunity arise such that LROC can capture a view of the Earth,” wrote LROC Principal Investigator Mark Robinson on the instrument’s website. “On the first of February of this year LRO pitched forward while approaching the north pole allowing the LROC WAC to capture the Earth rising above Rozhdestvenskiy crater (180-km diameter).”
Robinson went on to explain that the Earth is a color composite from several frames and the colors are very close to what the average person would see if they were looking back at Earth themselves from lunar orbit. “Also, in this image the relative brightness between the Earth and the Moon is correct, note how much brighter the Earth is relative to the Moon,” Robinson said.
Below is a gif image that demonstrates how images are combined over several orbits to create a full image from the Wide Angle Camera.
A gif image showing the “venetian blind” banding demonstrates how a WAC image is built up frame-by-frame. The gaps between the frames are due to the real separation of the WAC filters on the CCD. Credit: NASA/GSFC/Arizona State University.
The frames were acquired at two second intervals, so the total time to collect the sequence was 5 minutes. The video is faster than reality by a factor of about 20.