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

Same as → equation of the equinoxes.

→ nutation; → right ascension.

A drive mechanism used to move a radar beam in a circular, spiral, or conical path periodically.

Agent noun of → nutate.

1) Nourishing; providing nourishment or nutriment.
2) Containing or conveying nutriment, as solutions or vessels of the body.
3) A nutrient substance (Dictionary.com).

From L. nutrientem, pr.p. of nutrire, → nourish.

Fârmand, from present stem of fâridan, + -mand.

1) Any substance or matter that, taken into a living organism, serves to sustain it in its existence, promoting growth, replacing loss, and providing energy.
2) Anything that nourishes; nourishment; food (Dictionary.com).

From L. nutrimentum "nourishment; support," from nutrire, → nourish.

Fârâk, from present stem of fâridan, → nourish, + -âk (as in xorâk, pušâk, etc.).

1) The act or process of nourishing or of being nourished.
2) The science or study of, or a course of study in, nutrition, especially of humans (Dictionary.com).

Verbal noun from L. nutrire, → nourish.

A person who is trained or expert in the science of nutrition.

→ nutrition; → -ist.

1) Serving to nourish; providing nutriment; nutritious.
2) Of, pertaining to, or concerned with nutrition (Dictionary.com).

Adjective and agent noun from L. nutrire, → nourish.

Same as → night blindness; opposite of → hemeralopia.

L.L. nyctalopia, from Gk. nukt, → night + al(aos) "blind" + -opia, akin to ope "view, look," ops "eye."

Šabkuri, from šab, → night, + kuri "blindness," from kur, → blind.

The mean square noise voltage across a resistance in thermal equilibrium is four times the product of the resistance, Boltzmann's constant, the absolute temperature, and the frequency range within which the voltage is measured. → Johnson-Nyquist noise.

Named after Harry Nyquist (1889-1976), a Swedish-born American physicist, who made important contributions to information theory. → Johnson-Nyquist noise; → formula.

The highest frequency that can be determined in a Fourier analysis of a discrete sampling of data.

→ Nyquist formula; → frequency.

The minimum number of resolution elements required to properly sample a signal, such as a star image, without causing erroneous effects known as aliasing. For electronic imaging, this number is generally taken as 2 pixels across the seeing disk diameter at the half intensity points. Also called → Shannon's sampling theorem and → sampling theorem.

Named after Harry Nyquist (1889-1976), a Swedish-born American physicist, who made important contributions to information theory, and Claude Elwood Shannon (1916-2001), an American mathematician and pioneer of information theory; → theorem.