Why is specialized, space-based equipment often necessary for accurately measuring the temperature of the absolute hottest stars?

Answer

Much of their light is shifted into the ultraviolet spectrum, which the atmosphere largely blocks.

The light emitted by extremely hot stars is often shifted heavily toward the ultraviolet spectrum, which is largely blocked by the Earth's atmosphere, necessitating instruments placed in space for accurate measurement.

Why is specialized, space-based equipment often necessary for accurately measuring the temperature of the absolute hottest stars?
physicsastronomytemperaturestarshottest