Technical term for a thermometer that measures high temperatures, often without direct contact. Compare with 高温計 (こうおんけい), which is a more common synonym.
See also: 高温計
At the steelworks, the temperature of the blast furnace is measured with a pyrometer.
More common synonym for pyrometer. 高温度計 is a longer, more explicit form that is less frequently used.
Compound of 高温度 (こうおんど, 'high temperature') + 計 (けい, 'meter, gauge').