Photoheliography

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

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, [...]

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.