An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 13 Search : minimum
angle of minimum deviation
  زاویه‌ی ِ کژرفت ِ کمینه   
zâviye-ye kažraft kaminé

Fr.: angle de déviation minimale   

The angle between the light entering and exiting the prism when the light passing through the prism is parallel to the prism's base. Angle of minimum deviation (D) is used to measure the → index of refraction (n) of the prism glass, because: n = sin [(A + D)/2]/sin (A/2), where A is the → prism angle.

angle; → minimum; → deviation.

Dalton minimum
  کمینه‌ی ِ دالتون   
kamine-ye Dalton

Fr.: minimum de Dalton   

A 40-year period of unusually low → solar activity, from about 1790 to 1830. See also the → Maunder minimum.

Named after John Dalton (1766-1844), British meteorologist; → minimum.

local minimum
  کمینه‌ی ِ محلی   
kamine-ye mahali

Fr.: minimum local   

The point x = c in an → interval where the value of the → function  f(y) is smaller than the value anywhere else in that interval. In other words, f(c) ≤ f(x) for all x in the interval.

local; → minimum.

Maunder minimum
  کمینه‌ی ِ ماؤندر   
kamine-ye Maunder

Fr.: minimum de Maunder   

A period from about 1645 to 1715 when the number of → sunspots was unusually low. This → solar activity minimum is attested also through the increased content of carbon 14 in tree rings in that period. The reason is that the cosmic rays which produce 14C reach the Earth in a greater number when there is weak solar activity (see also → radiocarbon dating). The Maunder minimum occurred during a period of cooling of the Earth, called the → Little Ice Age. The Maunder minimum is one of a number of periods of low solar activity, including the → Dalton minimum, the → Sporer minimum, the → Wolf minimum , and the → Oort minimum.

After the British astronomer Edward Walter Maunder (1851-1928) who, along with Gustav Spörer of Germany, first called attention to this phenomenon; → minimum.

minimum
  کمینه   
kaminé (#)

Fr.: minimum   

The least value attained (or attainable) by a function; the opposite of maximum.

From L. minimum "smallest" (thing), neuter of minimus "smallest," superlative of → minor "smaller."

Kaminé, from kamin superlative of kam "little, few; deficient, wanting; scarce" (Mid.Pers. kam "little, small, few," O.Pers./Av. kamna- "small, few." Keh "small, little, slender" (related to kâstan, kâhidan "to decrease, lessen, diminish," from Mid.Pers. kâhitan, kâstan, kâhênitan "to decrease, diminish, lessen;" Av. kasu- "small, little;" Proto-Iranian *kas- "to be small, diminish, lessen") + nuance suffix.

minimum deviation
  کژرفت ِ کمینه   
kažraft-e kaminé

Fr.: déviation minimale   

Same as → angle of minimum deviation.

minimum; → deviation.

minimum orbit intersection distance (MOID)
  دورای کمینه‌ی ِ اندرسکنج ِ مدار   
durâ-ye kamine-ye andarsekanj-e madâr

Fr.: distance minimale d'intersection d'une orbite   

The minimum distance between the paths of two orbiting objects around a → primary. Such distance between an object and Earth is called Earth MOID.

minimum; → orbit; → intersection; → distance.

Oort minimum
  کمینه‌ی ِ اورت   
kamine-ye Oort

Fr.: minimum de Oort   

A 40-year period of unusually low → solar activity, from about 1010 to 1050. See also the → Maunder minimum.

Oort cloud; → minimum.

solar minimum
  کمینه‌ی ِ خورشیدی   
kamine-ye xoršidi

Fr.: minimum solaire   

The month(s) during the 11 year → solar cycle when the number of → sunspots is lowest.

solar; → minimum.

Spörer minimum
  کمینه‌ی ِ اشپورر   
kamine-ye Spörer

Fr.: minimum de Spörer   

A period of low → solar activity that lasted from about A.D. 1420 to 1570. It occurred before → sunspots had been studied, and was discovered by analysis of the proportion of carbon-14 in tree rings, which is strongly correlated with solar activity.

Named for the German astronomer Gustav Spörer (1822-1895); → minimum.

Sporer minimum
  کمینه‌ی ِ اشپورر   
kamine-ye Spörer

Fr.: minimum de Spörer   

A period of low → solar activity that lasted from about A.D. 1420 to 1570. It occurred before → sunspots had been studied, and was discovered by analysis of the proportion of carbon-14 in tree rings, which is strongly correlated with solar activity.

Named for the German astronomer Gustav Spörer (1822-1895); → minimum.

sunspot minimum
  کمینه‌ی ِ هورلک   
kamine-ye hurlak

Fr.: minimum des taches   

Periods of time when the → relative sunspot number is low. These periods of time occur approximately every 11 years and represent the minimum in the → sunspot cycle.

sunspot; → minimum.

Wolf minimum
  کمینه‌ی ِ ولف   
kamine-ye Wolf

Fr.: minimum de Wolf   

A 70-year period of unusually low → solar activity, from about 1280 to 1350. See also the → Maunder minimum.

Wolf number; → minimum.