Before it was photographed, the existence of a moon in Daphnis's position had already been inferred from gravitational ripples observed on the outer edge of the Keeler gap.
The discovery of Daphnis was announced by the Cassini Imaging Science Team Archived 2011-05-20 at the Wayback Machine on May 6, 2005.
[10] The discovery images were taken by the Cassini probe over 16 min on May 1, 2005, from a time-lapse sequence of 0.180 second narrow-angle-camera exposures of the outer edge of the A ring.
Both, particularly the inclination, are significantly greater than those of Pan (the larger moonlet which forms the Encke Gap).
The moon was discovered to be an irregularly-shaped object with a mostly smooth surface, a few craters, and an equatorial ridge.