Huon rested his hand upon it, and slowly a circular aperture opened.

The distribution for a perfectly circular aperture is known by the name "Airy rings".

From a circular aperture at its base, the second machine suddenly extruded a pair of long, rubbery arms.

The passage opened out into what was scarcely a room- more like a circular aperture.

It was headless, with a circular aperture between its shoulders.

The diffraction pattern given by a circular aperture is shown in the figure on the right.

At the far right of the panel, there was a shallow-rimmed circular aperture, just five or six millimeters wide.

If two leaves are used they have curved edges to create a roughly circular aperture.

Its large, circular aperture has a golden, pearly shine.

The disk shape is given by the circular aperture of the pupil.