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

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

   Homepage   
   


A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Number of Results: 4 Search : twilight
astronomical twilight
  نیمتاب ِ اخترشناسیک، ~ اخترشناختی   
nimtâb-e axtaršenâsik, ~ axtarsnâxti

Fr.: crépuscule astronomique   

The time between sunset or sunrise and the moment when the Sun's center lies 18° below the horizon. → civil twilight.

astronomical; → twilight.

civil twilight
  نیمتاب ِ شارین   
nimtâb-e šârin

Fr.: crépuscule civil   

The time between sunset or sunrise and the moment when the Sun's center lies 6° below the horizon. → astronomical twilight.

civil; → twilight.

nautical twilight
  نیمتاب ِ دریانوردیک   
nimtâb-e daryâ-navardik

Fr.: crépuscule nautique   

The period before sunrise and after sunset when the center of the Sun's disk is between 6° and 12° below the horizon.

nautical astronomy; → twilight.

twilight
  نیمتاب   
nimtâb (#)

Fr.: crépuscule   

The diffused light from the sky when the Sun is below the → horizon, either from daybreak to → sunrise or, more commonly, from → sunset to nightfall. There are three types of twilight: → astronomical twilight, → civil twilight, and → nautical twilight. They are divided on the basis of the → solar depression angle.

M.E., cognate with Du. tweelicht, Ger. zwielicht, from twi- a combining form meaning "two, twice," but it appears to refer to "half" light, rather than the fact that twilight occurs twice a day + → light.

Nimtâb, from nim, nimé, → half, + tâb "light," present stem of tâbidan "to shine," → luminosity.