Spectroheliograph

Rarity: Common

The most frequent rarity: most Wikipedia articles become Commons.

Rarity follows how well known the article is: its views on the French and English Wikipedia over a year, and the number of languages it exists in.

At a glance

Class

Invention

Domain

Science and technology

Knowledge cost

1

In collections

Nobody has pulled it yet.

What Wikipedia says

The spectroheliograph is an instrument used in astronomy which captures a photographic image of the Sun at a single wavelength of light, a monochromatic image. The wavelength is usually chosen to coincide with a spectral wavelength of one of the chemical elements present in the Sun.

Excerpt from the Wikipedia article “Spectroheliograph”, under the CC BY-SA 4.0 license. Read the article on Wikipedia

Image: Unknown author, Public domain, via Wikimedia Commons.