Temperature of the Sun is measured by?

Pyrometer measures higher temperature with measuring radiation emitted by source. In a  mercury thermometer , a glass tube is filled with  mercury  and a standard temperature scale is marked on the tube. With changes in temperature, the  mercury  expands and contracts, and the temperature can be read from the scale.  Mercury thermometers  can be used to determine body, liquid, and vapor temperature . Odometer  definition, an instrument for measuring distance traveled, as by an automobile.    Telemeter is an electrical apparatus for measuring a quantity (such as pressure, speed, or temperature) and transmitting the result especially by radio to a distant station.