NASA’s Lunar Reconnaissance Orbiter (LRO) experiences 12 “earthrises” every day, however is almost always busy imaging the lunar surface so only rarely does an opportunity arise such that LROC can capture a view of Earth.
Image © NASA/Goddard/Arizona State University
On Feb. 1, 2014, LRO pitched forward while approaching the moon‘s north pole allowing the LROC Wide Angle Camera to capture Earth rising above Rozhdestvenskiy crater (112 miles, or 180 km, in diameter).
The LROC WAC is very different than most digital cameras. Typically resolution is reported as the number pixels in a single image; a cell phone camera today has more than 5 million pixels (5 megapixels). A single WAC frame has only 9,856 pixels, however the WAC builds up a much larger image by exposing a series of images (or frames) as LRO progresses in its orbit; this type of imaging is called “push-frame.” Over a full month as the LRO orbit track progresses around the moon the WAC builds up a collection of images that covers the entire globe.