45 years ago this coming Christmas eve, Apollo 8 astronauts Frank Borman, Jim Lovell and William Anders became the first humans to leave Earth's orbit and circle the moon. But the more memorable part of the mission was its famous "Earthrise" photo, showing Earth for the first time rising above the lunar landscape. No human had ever seen our planet from space yet.

In Life's "100 Photographs That Changed the World," acclaimed wilderness photographer Galen Rowell described the unprecedented view of Earth as "the most influential environmental photographic ever taken."

Earthrise is now one of the most reproduced space photos of all time.

"Of all the objectives NASA had set before launch, no one had thought of photographing the earth from lunar orbit," Robert Zimmerman wrote in his book "Genesis: The Story of Apollo 8 : the First Manned Flight to Another World."

The photo was taken during the spacecraft's fourth pass around the moon, and the spacecraft had changed its orbit making it possible to see Earth while it climbed above the lunar horizon.

None of the astronauts were prepared for that. Anders, who had been in charge of photography, described the sequences of events to BBC in an interview :
I don't know who said it, maybe all of us said, 'Oh my God. Look at that!' and up came the Earth. We had had no discussion on the ground, no briefing, no instructions on what to do. I jokingly said, 'well it's not on the flight plan,' and the other two guys were yelling at me to give them cameras. I had the only color camera with a long lens. So I floated a black and white over to Borman. I can't remember what Lovell got. There were all yelling for cameras, and we started snapping away.
Apparently, there was also controversy over which astronaut, Borman or Anders, pushed the camera button.  Both claimed they did, and investigation into transcripts later revealed that Anders took the iconic color photography, while Borman was the first to recognize "Earthrise", and took the first photo - which was in black and white. Obviously the color photo was the winning one.

In "The Elusive Apollo 8 Earthrise Photo," author Fred Spier contends that command module pilot Lovell also played his part — it was his authority that moved Anders to take the shot:
Experienced astronaut Frank Borman was the first to the importance of the picture, while equally experienced astronaut James Lovell was quick to follow. Space rookie William Anders, however, was in charge of taking the photos. In doing so, Anders had to follow a rather tight and well-defined photo plan, in which there was little or no room for unplanned snapshots, as he complained later during a debriefing session. As a result, Anders first offered some resistance and then quickly did what the other told him to do. Although it now seems beyond doubt that Anders actually snapped the famous picture, it also seems fair to say the picture came as a result of the combine efforts of all three astronauts.