A sensitive instrument can detect changes of as little as one arc second.

The new European telescope has a resolving power of .17 arc seconds.

In 1994, the two stars were separated by 5.1 arc seconds, which is equivalent to 112.41 astronomical units.

The second is only separated by 8.7 arc seconds, and is magnitude 12.9.

The star has a high proper motion across the sky, advancing 1.304 arc seconds per year.

This improves the image quality and accuracy (average between 1-2 arc seconds).

The two stars are currently separated by 14.5 arc seconds.

The angular diameter of Jupiter likewise varies from 50.1 to 29.8 arc seconds.

The two stars are separated by about 74 arc seconds ( 434 AU).

The azimuth could be set to an accuracy of 5 arc seconds.