Heliometer

A heliometer (from Greek ἥλιος hḗlios "sun" and measure) is an instrument originally designed for measuring the variation of the Sun's diameter at different seasons of the year, but applied now to the modern form of the instrument which is capable of much wider use.^[1]

^ One or more of the preceding sentences incorporates text from a publication now in the public domain: Gill, David (1911). "Heliometer". In Chisholm, Hugh (ed.). Encyclopædia Britannica. Vol. 13 (11th ed.). Cambridge University Press. pp. 224–230.

[EB1911-1] One or more of the preceding sentences incorporates text from a publication now in the public domain: Gill, David (1911). "Heliometer". In Chisholm, Hugh (ed.). Encyclopædia Britannica. Vol. 13 (11th ed.). Cambridge University Press. pp. 224–230.

[1]