GeezerVison

In optical engineering and telecommunications engineering, the flick is a unit of spectral radiance. One flick corresponds to a spectral radiance of 1 watt per steradian per square centimeter of surface per micrometer of span in wavelength (W·sr⁻¹·cm⁻²·μm⁻¹). This is equivalent to 10¹⁰ watts per steradian per cubic meter (W·sr⁻¹·m⁻³). In practice, spectral radiance is typically measured in microflicks (10⁻⁶ flicks).^[1] One microflick is equivalent to 10 kilowatts per steradian per cubic meter (kW·sr⁻¹·m⁻³).^[2]

In radio astronomy, the unit flik was coined by a group at Lockheed in Palo Alto, California as a substitute for the SI derived unit W cm⁻² sr⁻¹ μm⁻¹, or watts divided by centimeters squared, steradians, and micrometers.^[3] While originally used only at Lockheed, many in the radio astronomy field adopted its use.