Heliograph

[hee-lee-uh-graf, -grahf] /ˈhi li əˌgræf, -ˌgrɑf/

noun
1.
a device for signaling by means of a movable mirror that reflects beams of light, especially sunlight, to a distance.
2.
Astronomy. .
3.
Meteorology. an instrument for recording the duration and intensity of sunshine.
4.
Photography, Printing. an early type of photoengraving made on a metal plate coated with sensitized asphalt.
verb (used with or without object)
5.
to communicate by heliograph.
/ˈhiːlɪəʊˌɡrɑːf; -ˌɡræf/
noun
1.
an instrument with mirrors and a shutter used for sending messages in Morse code by reflecting the sun’s rays
2.
a device used to photograph the sun
n.

product of a certain type of engraving process, 1853, from helio- + -graph “something written.” Earlier, “a description of the sun” (1706, implied in heliographic). Heliography (1845 in the engraving sense) also (1840) was an early term for what came to be called photography.