An instrument which measures the height of the cloud base.
An instrument that automatically records cloud height.
An instrument that is used to measure the angular elevation of a projected light on the base of a cloud. It measures the angle of the cloud base included by the observer (or machine), the ceiling light and the illuminated spot on the cloud.
an automatic, recording, cloud-height indicator. A light is projected upward onto the cloud base; the reflected light is detected by a photocell, and the height is determined by triangulation (the unique point where three line meet).
A ceilometer is a device using a laser or other light source to determine the height of a cloud base.