• Saturn's rings along with its trio of moons, Rhea, Enceladus and Atlas.

Saturn's rings along with its trio of moons, Rhea, Enceladus and Atlas. (Photo : NASA/JPL-Caltech/Space Science Institute)

NASA just revealed a unique Image of the Day on Monday, depicting Saturn's majestic rings that span out across the pitch black darkness of space along with three of its moons.

Rhea is spotted above the expanse of the rings and Enceladus is seen beneath the rings however, there is one more moon that is hiding somewhere in the photo taken by the Cassini spacecraft, challenging the viewer to search for this elusive moon. 

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Upon enlarging this image, you can see the details of each moon as NASA describes Rhea appearing rather large beneath the rings at 949 miles across in diameter where the icy Enceladus is just 313 miles wide as it shines brightly as a crescent above Rhea.

The missing moon known as Atlas which is only 19 miles across, making it tiny compared to the others in the photo.

Atlas also possesses a strange shape, and is also one of the more than 60 moons that are currently in orbit around the ringed giant. This moon is apparently so tiny that NASA's Voyager spacecraft has not discovered it up until 1980. The most recent image of Atlas was taken earlier in December 2015, located some 20,000 miles away from Cassini.

This image featured on Monday was captured last September 24 from a distance of 1.8 million miles from Rhea, 1.3 million miles from Enceladus and 1.5 million miles from Atlas. 

Still looking for Atlas? NASA reveals that the tiny satellite is located within Saturn's F ring just above Rhea, the biggest moon on the photo, on its upper left. Upon closer inspection, the thin bottom line of Saturn's rings is hiding the elusive Atlas, appearing like a tiny bump or a dot of dust.