Most people will require optical aid (large binoculars or a telescope) magnifying at least 20x to clearly resolve Saturn's rings.

The only man-made structure on the island is a daymark, which serves as an optical navigational aid for ships.

Although easy to locate in the northern sky, observing the Double Cluster in its two parts requires optical aid.

Across the eyes a complicated contraption served as an optical aid, with artificial eyelids which opened and closed at measured intervals.

Without any optical aid he is able to perceive and identify objects of microscopic size.

He calls it "an optical and therapeutic aid that helps [some colorblind people] better use what vision they have."

The comet was spotted without optical aid on 7 February 2013 at a magnitude of 6.

The brighter star should be easily visible without optical aid under dark skies in the southern hemisphere.

To see some details of the planets you will need some sort of optical aid.

Normal-sighted people can see at least seven individual stars without optical aid, and binoculars raise the total to dozens.