a signalling device by which sunlight is reflected in flashes from a movable mirror

a telescopic apparatus for photographing the sun

a type of early photographic engraving made using a sensitized silver plate and an asphalt or bitumen varnish

send (a message) by heliograph

the glasses seemed to be heliographing a warning

take a heliographic photograph of

he could only heliograph static subjects in very intense light