second of arc

noun

1. second ²( def 4 ).

Example Sentences

By comparison, the human eye can resolve structures separated by at best about 40 seconds of arc, and even the Hubble Space Telescope can achieve a resolution of only about 0.04 second of arc.

From Scientific American

A second of arc is about the size of a star as it appears to the eye under the best and calmest of conditions from a mountaintop observatory.

From Seattle Times

According to Einstein’s final version of the theory, completed in 1915, as their light rays curved around the sun during an eclipse, stars just grazing the sun should appear deflected from their normal positions by an angle of about 1.75 second of arc, about a thousandth of the width of a full moon.

From Seattle Times

A second of arc is about the size of a star as it appears to the eye under the best and calmest of conditions from a mountaintop observatory.

From New York Times

According to Einstein’s final version of the theory, completed in 1915, as their light rays curved around the sun during an eclipse, stars just grazing the sun should appear deflected from their normal positions by an angle of about 1.75 second of arc, about a thousandth of the width of a full moon.

From New York Times