Neutron star had large magnetic fields, then electromagnetic waves would be emitted. Unbeknown to him, radio astronomer Antony Hewish and his research assistant Jocelyn Bell at Cambridge were shortly to detect radio pulses from stars that are now believed to be highly magnetized, rapidly spinning neutron stars, known as pulsars. In 1965, Antony Hewish and Samuel Okoye discovered "an unusual source of high radio brightness temperature in the Crab Nebula". This source turned out to be the Crab Pulsar that resulted from the great supernova of 1054. In 1967, Iosif Shklovsky examined the X-ray and optical observations of Scorpius X-1 and correctly
Laser beam quality as shown in the figure. However, when a multimode beam is focused, Equation (3) becomes M cannot be determined from a single beam profile measurement. The ISO/DIS 11146 define that M should be calculated from a series of measurements as shown in the figure below. M is measured on real beams by focusing the beam with a fixed position lens of known focal length, and then measuring the characteristics of the beam waist and divergence. These measurements can be taken with a laser beam profiler. The multiple measurements ensure that the minimum beam diameter is found and enable a "curve