Sentence examples for arcsecond from inspiring English sources

This device measures sky brightness in units of magnitudes per square arcsecond (magnitude is a measure of brightness, the lower the number the brighter the sky; square arcseconds is a measure of area, where one arcsecond is 1/3600 of a degree).

In my back garden in the suburbs of Glasgow the SQM reads about 18 magnitudes per square arcsecond.

The equinoxes drift westward along the ecliptic at the rate of 50.3 arcseconds annually as the celestial equator moves with Earth's precession.

Despite being in constant high-speed motion, it can lock on to a target celestial object and track it continuously without its gaze wandering by more than 0.007 "arcseconds" – the width of a human hair seen at a distance of 1.5km.

As Mr. Rees documents, the men lacked the benefit of roads, electricity or the digital precision allowed by satellite technology; as a result, on average, the markers are three arcseconds (i.e. 295 feet) north or south of the 49th parallel [2].

Feynman (1963, p. 697) gives an example that highlights this difference in magnitudes more dramatically by showing how the gravitational coupling between a proton and an electron in a hydrogen atom would shift the wave-function of an electron by just 43 arcseconds over a time period of 100 times the age of the Universe!