Washington, April 6 -- More than 50 years after humans first flew around the Moon, Artemis astronauts will repeat the feat on Monday and use the most basic instrument to study it: their eyes. Despite the technological advancements since the Apollo missions, Nasa still relies on the eyesight of its astronauts to learn more about the Moon. "The human eye is basically the best camera that could ever or will ever exist," said Kelsey Young, lead scientist for the mission. "The number of receptors in the human eye far outweighs what a camera is able to do." Although modern cameras may be superior to human eyesight in some respects, "the human eye is really good at color, and it's really good at context, and it's also really good at photometric ob...