It has also been claimed that an obscure entry in a number of Irish monastic annals originally referred to SN 1054 but was subsequently corrupted, becoming in the process an allegorical fantasy based on the legend of the Antichrist.
The cloudy remnants of SN 1054 are now known as the Crab Nebula. The nebula is also referred to as Messier 1 or M1; being the first Messier Object cataloged in 1774. X-rays from this object were detected in April 1963 with a high-altitude rocket of type Aerobee with an X-ray detector developed at the Naval Research Laboratory; the X-ray source was named Taurus X-1, and the energy emitted in X-rays by the Crab nebula is about 100 times more than that emitted in the visual light.
A pulsating radio source, now known as the Crab Pulsar, lies in the heart of the nebula.