Definition:
heliograph
- heliographan apparatus for signalling by means of a movable mirror which reflects flashes of sunshine / to signal by heliograph
- heliographinstrument for photographing the sun, consisting of a camera and a specially adapted telescope
- heliographdevice for signaling by means of a movable mirror that reflects beams of light, esp. sunlight, to a distance
- heliographinstrument for recording the duration and intensity of sunshine
- heliographto communicate by heliograph