from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An apparatus for viewing the sun without injuring the eye.
from the GNU version of the Collaborative International Dictionary of English
- n. A telescope or instrument for viewing the sun without injury to the eyes, as through colored glasses, or with mirrors which reflect but a small portion of light.
from The Century Dictionary and Cyclopedia
- n. A form of telescope fitted for viewing the sun without pain or injury to the eyes, as an instrument made with colored glasses or glasses blackened by smoke, or with mirrors formed simply of surfaces of transparent glass, which reflect but a small proportion of light.
Modern telescopes on display include a helioscope, which is used to observe the sun because it can't be viewed directly through a telescope.
To the "helioscope" employed by Father Scheiner  two centuries and a quarter earlier, a species of micrometer was added.
Hippo-hopparray helioscope flashed winsor places as the gates might see.
Each insect, wakened but an hour ago by the warmth of the moist soil, in an abandonment of the moment, is a helioscope transmitting signals of pure pleasure.
According to Poggendorf, the invention of the helioscope is ascribed to him.
He made use of a helioscope composed of coloured glasses in the beginning, but afterwards conceived the idea of projecting the sun's image on a screen in order to study its surface.
(1610-1616), who, with the helioscope invented by him, discovered the sun spots and calculated the ime of the sun's rotation; and the poet,