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

A short distance from the target, in right ascension, where the telescope is pointed for various purposes.

→ alpha; → offset.

In → CCD detectors, same as → bias and → offset.

→ bias; → offset.

A short distance from the target, in → declination, where the → telescope is pointed for various purposes.

→ delta; → offset.

1) A shift in the pointing position of a telescope with respect to a reference position.
2) Another term for the → bias in → CCD detectors.
3) Surveying: A short distance measured perpendicularly from a main survey line.

→ off- + → set.

Ap-, → off-; + neh present stem of nehâdan "to place, put; to set" Mid.Pers. nihâtan; Av. ni- "down; below; into," → ni-, + dā- "to put; to establish; to give," dadāiti "he gives;" cf. Skt. dadāti "he gives;" Gk. didomi "I give;" L. do "I give;" PIE base *do- "to give."

Guiding an astronomical exposure on a star, when the object of interest is nearby, but invisible.

→ offset; → guiding.