vertical circle

Flames from a driftwood fire lit the faces of two dark, wooden spirit boards making tight vertical circles in the hands of elders, their cheekbones smudged with red circles.

The elevation of a point, or star, or other celestial object, above the horizon, measured by the arc of a vertical circle intercepted between such point and the horizon.

Theodolite, about 1780, brass; horizontal circle 5 in., vertical circle 5 in., telescope 7-1/2 in., compass 3 in.; spirit level set into compass card; spirit level attached to telescope; fixed vertical circle; unsigned.

A vertical circle passing through the sun may also be seen.

In these instruments the crystal is set up and adjusted once for all, with the axis of a prominent zone parallel to the axis of either the horizontal or the vertical circle.