What Is a Helioscope?

Scheiner's helioscope

The sun is the only astronomical object that has too much light in order to observe it. A helioscope is an instrument used in observing the sun. The helioscope was first used by Benedetto Castelli (1578-1643) and refined by Galileo (1564–1642). The method involves projecting an image of the sun onto a white sheet of paper suspended in a darkened room with the use of a telescope.

The first heliotropii telioscopici or helioscope was designed by Christoph Scheiner (1575 –1650) to assist his sunspot observations.

WARNING: Under no circumstances should a telescope, binoculars, magnifying glass, or any other such magnifying instrument be used to observe the sun directly. This can result in instant blindness.