HELIOGRAPH
- an apparatus for signalling by means of a movable mirror which reflects flashes of sunshine [n -S] / to signal by heliograph [v -ED, -ING, -S]
- device for signaling by means of a movable mirror that reflects beams of light, esp. sunlight, to a distance
- instrument for photographing the sun, consisting of a camera and a specially adapted telescope
- instrument for recording the duration and intensity of sunshine
- to communicate by heliograph