A pulsar (short for pulsating radio star) is a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. This radiation can be observed only when the beam of emission is pointing toward Earth, much the way a lighthouse can be seen only when the light is pointed in the direction of an observer, and is responsible for the pulsed appearance of emission. Neutron stars are very dense, and have short, regular rotational periods. This produces a very precise interval between pulses that range roughly from milliseconds to seconds for an individual pulsar. Pulsars are believed to be one of the candidates of high and ultra-high energy astroparticles (see also Centrifugal mechanism of acceleration).

Yukon Advanced Optics Worldwide is a Lithuanian company that designs and manufactures outdoor optics, including binoculars, spotting scopes, rifle sights, rangefinders, and a selection of night vision systems. Recently, the company has ventured into the thermal imaging market, with a British made thermal imager, the Pulsar Quantum.