Analysis of information sources in references of the Wikipedia article "Потік Крабовидної туманності" in Ukrainian language version.
It’s routinely used for instrument calibration and even as a unit of measure, the “millicrab.” An unexpectedly varying Crab Nebula might have affected any research that used the Crab as a standard or a calibration tool.
Various X-ray satellites have used the Crab as a standard candle to perform their calibrations in the past
These characteristics led astronomers to regard the Crab Nebula as a standard candle, up to the point that fluxes in high-energy astrophysics are customarily measured in units of the Crab's flux.
the 'crab' was commonly used in the early days of X-ray astronomy
It’s routinely used for instrument calibration and even as a unit of measure, the “millicrab.” An unexpectedly varying Crab Nebula might have affected any research that used the Crab as a standard or a calibration tool.
Various X-ray satellites have used the Crab as a standard candle to perform their calibrations in the past
the 'crab' was commonly used in the early days of X-ray astronomy
