  Observing artificial satellites is a relatively new and unique branch of
astronomy that is very interesting and dynamic. One specific aspect of
observing these objects is that although they appear amongst the celestial
background, as deep-sky objects do, their apparent locations amongst this
background depend on where you are standing on Earth at a given time. This
effect is known as parallax. When a satellite is observed at a specific time
from a specific location, the satellite's equatorial coordinates can be
determined using astrometric means. Its range from the observer, however, is
still unknown unless the observer knows the satellite's precise orbit elements
or has easy access to a radar station. However, when two or more observers,
separated by some distance, observe the same satellite at the same time, their
observations can be used to determine the range of the satellite using the
satellite's observed trigonometric parallax.
