An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

Of or pertaining to a parallax.

Adj. form of → parallax.

Of an object in the sky, the angle between the → celestial pole, the object, and the → zenith. Since parallactic angle describes the orientation on the sky of the object for a particular observer, it can be an important quantity in some observations.

→ parallactic; → angle.

The path on the sky of the apparent position of a star as seen from the Earth, due to the Earth's annual motion around the Sun.

→ parallactic; → ellipse.

An irregularity in the Moon's motion caused by the Sun's gravitational attraction, which sets the Moon ahead or behind its normal orbital position. The Moon is about 2 arcminutes ahead of its expected position at first quarter, and a similar amount behind at last quarter.

→ parallactic; → inequality.

The proper motion of a star due to the effect of the Sun's motion relative to the → local standard of rest.

→ parallactic; → motion.