India, Oct. 4 -- Saturn reaches opposition on October 4, putting the ringed planet among the highlights of the October night sky. The event brings Saturn closer to Earth for the year and makes it visible for much of the night, but there is another phenomenon that makes the occasion particularly interesting for observers: the Seeliger effect, or opposition surge.

Opposition occurs when Earth passes between the Sun and an outer planet. From Earth, the planet then appears opposite the Sun in the sky. As a result, Saturn rises around sunset and remains visible for most of the night. NASA has listed October 4 as one of October's major skywatching events, noting that the geometry makes Saturn especially well placed for observation.

According ...