Two are used to point and lock the telescope onto the target, and the third can be used for position measurements - also known as astrometry.

Together with timing systems, velocity and acceleration data can be developed from the position measurements.

As a result, no detector carrying out proper position measurements on the object will ever produce results that are different from each other.

Tycho Brahe used a sextant for many of his stellar position measurements.

A position sensor is any device that permits position measurement.

The procedure works by taking multiple position measurements to determine the gravitational deflection caused when two or more asteroids move past each other.

These atlases were especially helpful in the early days of position measurements of artificial satellite.

Includes position measurements and images.

It does this by taking position measurements so accurate that tracks can be reliably reconstructed using just a few measurement points.

The epoch for the position measurements in the latest edition is J2000.0.