from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Plural form of photoheliograph.
Sorry, no etymologies found.
Under his direction, Mr Dallmeyer has advanced far in the preparation of five photoheliographs ....
There will thus be available for observation of the Transit of Venus 23 telescopes, nine of which will be provided with double-image-micrometers; and five photoheliographs; and for determination of local time, and latitude and longitude, there will be nine transits and six altazimuths ....
Originally five stations were selected and fully equipped with equatoreals, transits, altazimuths, photoheliographs, and clocks; but I have since thought it desirable to supplement these by two branch stations in the Sandwich Islands and one in Kerguelen's Island; and the additional instruments thus required have been borrowed from various sources, so that there is now an abundant supply of instrumental means ....
With regard to the photoheliographs it is proposed to make trial of a plan proposed by M. Janssen, for numerous photographs of Venus when very near to the Sun's limb.
Historical records from days when the observatory kept time for the city and glass-encased photoheliographs, used to photograph the sun, are glimpses into the past, when what was written in the stars affected everyday life.
A Janssen slide, capable of taking 50 photographs of Venus and the neighbouring part of the Sun's limb at intervals of one second, has been made by Mr Dallmeyer for each of the five photoheliographs.” ”