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

1) Recognized or accepted as being true or reliable.
2) Exercising or asserting authority; commanding.
3) Possessing or supported by authority; official (Dictionary.com).

From authorit(y), → authority, + suffix -ative.

1) The power to determine, adjudicate, or otherwise settle issues or disputes; jurisdiction; the right to control, command, or determine (Dictionary.com).
2) A person or body of persons in whom authority is vested, as a governmental agency (Dictionary.com).

→ author; → -ity.

Dâtârgân, from dâtâr, → author, + -gân, on the model of xodâygân "a great lord."

1) The act, fact, or occupation of writing.
2) Source or origin, as of a book or idea.

→ author.

Gk., from autos "self, one's own," of unknown origin.

Xod-, from xod "self," Av. hva- "self, own."

1) In radio astronomy, a process performed by an → autocorrelator.
2) In statistics, a linear relation between values of a random variable over time.
3) In electronics, a technique used to detect cyclic activity in a complex signal.

Autocorrelation, from → auto- "self" + → correlation.

Xod-hambâzâneš, from xod- "self" + hambâzâneš, → correlation.

A mathematical function that describes the correlation between two values of the same variable at different points in time.

→ autocorrelation; → function.

In radio astronomy, a spectrograph which correlates the signal with itself with various time delays, and extracts the frequency spectrum of the signal. → correlator.

Autocorrelator, agent n. from → autocorrelate + → -or.

Xod-hambâzângar, agent n. from xod-, → auto-, + hambâzângar, → correlator.

The → covariance of a → time series overt time.

→ auto-; → covariance.

The autocovariance function (ACF) is defined as the sequence of covariances of a stationary process.
A mathematical function that expresses the autocovariance of a series in terms of the interval of separation.

→ autocovariance; → function.

An electronic equipment used to automatically guide a telescope during long exposures.

Autoguider from → auto- "self" + guider, from O.Fr. guider "to guide, lead, conduct," from Germanic origin; akin to O.E. wltan "to look after" witan "to know," akin to O.H.G. wizzan "to know," L. videre "to see," Gk. eidenai "to know," idein "to see," Av. vaêd- "to know," Skt. veda "knowledge; finding."

Xodrâhbar from xod-, → auto + râhbar "guide," from râh "way" + bar, from bordan "to lead."

The act or process of guiding a telescope automatically.

→ autoguider.

Having a self-acting or self-regulating mechanism.

From Gk. automatos "self-acting," from → auto- + matos "willing," from PIE *men- "to think;" compare with Av./O.Pers. man- "to think."

Xodkâr from xod-, → auto-, + kâr "acting, actor," from kardan "to do, act."

A telescope developed to perform photometric observations automatically.

→ automatic; → photometric; → telescope.

An → isomorphism between an → object and itself.

→ auto-; → morphism.

1) Self-governing; independent; subject to its own laws only; having autonomy.
2) Pertaining to an autonomy, or a self-governing community.
3) Biology: Existing and functioning as an independent organism. Growing naturally or spontaneously, without cultivation (Dictionary.com).

Adjective from → autonomy.

1) Independence or freedom, as of the will or one's actions.
2) The condition of being autonomous; self-government or the right of self-government (Dictionary.com).

→ auto-; → -nomy.

The season of the year between summer and winter; it begins in the northern hemisphere at the → autumnal equinox and ends at the → winter solstice.

O.Fr., from L. autumnus, a word probably of Etruscan origin.

Pâyiz, from Mid.Pers. pâdiz or pâtez, from Proto-Iranian *pâti-z(a)ya- "near winter," from pâti "near" + *z(a)ya- "winter," compare with Av. zyan- or zyam- "winter" (Skt. heman, Gk. xeimon, L. hiems).

→ autumnal equinox.

→ autumn; → equinox.

One of the two points where the → ecliptic crosses the → celestial equator. At the autumnal equinox the Sun appears to be moving across the equator from the northern celestial hemisphere to the southern celestial hemisphere. The instant of the event.

→ autumn; → -al; → equinox.

A number representing a group of quantities, obtained by adding each quantity of the group and dividing the total by the number of quantities. Same as → arithmetic mean.

From O.Fr. avarie "damage to ship," from It. avaria or maybe avere, O.Fr. aveir "property, goods," from L. habere "to have." Meaning shifted to "equal sharing of such loss by the interested parties."

Miyângin "the middle; middle-sized; the middle pearl in a string," from miyân, → middle, + -gin a suffix forming adjectives of possession.