Temperature measurement scale where, at standard atmospheric pressure, the freezing point of water is 32 °F and the vaporization point of water is 212 °F. To convert from Celsius, use F = (C x 1.8) + 32.
A measurement distance sufficiently large (typically greater than 10 times the focal distance) whereby the spot size of an instrument is growing in direct proportion to the distance from the instrument, and the field of view is constant.
The area or solid angle viewed through an optical or infrared instrument. Typically expressed by giving the spot diameter of an instrument and the distance to that spot. Also expressed as the angular size of the spot at the focal point. See Optical or Infrared Resolution.
The point or distance from the instrument at which the object is focused onto the detector within the instrument. The focal point is the place or distance at which the optical or infrared resolution is greatest.
The frost point is the temperature up to which the gas is to be cooled down so that straight water vapour gets condensed to ice. The frost point is valid only for temperatures below the freezing point.
The temperature measurement accuracy expressed as a percentage of the maximum possible reading of an instrument.