According to Mark Showalter, a planetary astronomer at the SETI Institute in California who discovered the moon, the newfound object is almost 100 million times fainter than the faintest star visible to the naked eye. But by tracking the movements of a mysterious white dot visible on Neptune photographs taken by Hubble between 2004 and 2009, he managed to pin down this mini-moon [OK?].
“The moons and arcs orbit very quickly, so we had to devise a way to follow their motion in order to bring out the details of the system,” he said. “It’s the same reason a sports photographer tracks a running athlete—the athlete stays in focus, but the background blurs,” said Showalter in a NASA statement.