Wanner optical pyrometer

Wanner optical pyrometer

[¦wän·ər ¦äp·tə·kəl pī′räm·əd·ər]
(engineering)
A type of polarizing pyrometer in which beams from the source under investigation and a comparison lamp are polarized at right angles and then passed through a Nicol prism and a red filter; the source temperature is determined from the angle through which the Nicol prism must be rotated in order to equalize the intensities of the resulting patches of light.