In one of Whitley Streiber's books he refers to a UFO witness whose eyesight was so good he could see the moons of Jupiter unaided. Is this even possible?

serpa

Magnitude 6.5 is the approximate limit of naked eye viewing. http://en.wikipedia.org/wiki/Apparent_magnitude All four Galilean moons are bright enough that they could, if they were farther away from Jupiter, be sighted from Earth without a telescope. (They are, however, easily visible with even low-powered binoculars.) They have apparent magnitudes between 4.6 and 5.6 when Jupiter is in opposition with the Sun,[39] and are about one unit of magnitude dimmer when Jupiter is in conjunction. The main difficulty in observing the moons from Earth is their proximity to Jupiter since they are obscured by its brightness.[40] The maximum angular separations of the moons are between 2 and 10 minutes of arc from Jupiter,[41] close to the limit of human visual acuity. Ganymede and Callisto, at their maximum separation, are the likeliest targets for potential naked-eye observation. The easiest way to observe them is to "cover" Jupiter with an object, e.g., a tree limb or a utility pole that is perpendicular to the plane of the moons' orbits. http://en.wikipedia.org/wiki/Galilean_moons For possible naked eye observations read this: http://denisdutton.com/jupiter_moons.htm Jun 13 10, 10:21 AM