different between photoheliographs vs photoheliography

English

Noun

photoheliographs

1. plural of photoheliograph

English

Etymology

photo- +? heliography

Pronunciation

• Rhymes: -????fi

Noun

photoheliography (uncountable)

1. Heliography (photography of the sun), especially as undertaken using a photoheliograph.
   • 1860, Photographic news for amateur photographers, volumes 3-4, page 113:

     The difficulties of photoheliography consist principally in the rapidity with which the sun's image acts upon the sensitive film.

   • 1860, Report of the annual meeting of the British Association for the Advancement of Science, volume 29, page 150:

     Difficulties of Photoheliography. — Whilst in lunar and stellar photography many of the obstacles to be overcome arose from the deficiency of photographic power in the unenlarged focal images of those celestial objects, the difficulties which have stood in the way of producing good sun-pictures arose in a great degree from the incomparably greater brilliancy in the sun's image, [...]

   • 1872, Nature, volume 5, page 497:

     First, that the system of photoheliography, which has for some years been carried on at Kew by the zeal of individuals, and partly maintained by private means, has now been brought to a close.