Lunar Occultation of X-ray Emission from the Crab Nebula

Science  13 Nov 1964:
Vol. 146, Issue 3646, pp. 912-917
DOI: 10.1126/science.146.3646.912


The x-ray flux from the Crab Nebula was observed during a lunar occultation on 7 July 1964. As the moon covered the central region of the nebula, the x-ray flux decreased gradually. The source appears to extend over a volume about 1 light-year in diameter.