How do you observe the Crab Nebula's pulsar?

The Crab Nebula's pulsar, also known as PSR B0531+21, is a highly-magnetized, rotating neutron star located at the center of the Crab Nebula. It emits regular pulses of radiation in the radio, optical, X-ray, and gamma-ray parts of the electromagnetic spectrum. To observe the pulsar, astronomers use a variety of techniques and instruments depending on the desired wavelength range.

At radio wavelengths, astronomers use large, single-dish telescopes or arrays of smaller dishes to detect the pulsar's periodic signals. The most sensitive radio telescopes currently in operation are the Green Bank Telescope and the Arecibo Observatory, although the latter was severely damaged in 2020 and is no longer in use.

For optical observations, astronomers use large ground-based telescopes equipped with sensitive cameras and spectrographs to study the pulsar's emission lines and measure its spin rate. One of the most successful optical observatories for pulsar studies is the William Herschel Telescope on La Palma in the Canary Islands.

X-ray and gamma-ray observations of the Crab Nebula's pulsar require space-based telescopes, as Earth's atmosphere absorbs most of these high-energy photons. The most famous X-ray observatory is the Chandra X-ray Observatory, while the Fermi Gamma-ray Space Telescope is one of the most sensitive gamma-ray observatories currently in operation.