How did astronmers use technology to indenifty characteristic of the crab nebula

technology that detects radio waves identified a pulsar at the center of the nebula

Explanation:

This detected radio source, determined to be pulse-like, was identified to be coming from a pulsating star called a pulsar. The charged particle emitted by the rapidly rotating star is emitted as synchrotron radiation in the radio spectrum. The pulsation was discovered to be at the rate of 30 times a second. Crab nebula is a nebula cloud made from a supernova