astronomical twilight

The period before sunrise and after sunset when sun’s center is between 12° and 18° below sea-level horizon. This may be regarded for all practical purposes as synonymous with complete darkness.

Aviation dictionary. 2014.

Look at other dictionaries:

  • astronomical twilight — astronominė prieblanda statusas T sritis Gynyba atitikmenys: angl. astronomical twilight pranc. crépuscule astronomique ryšiai: platesnis terminas – prieblanda …   NATO terminų aiškinamasis žodynas

  • astronomical twilight — either of two periods of partial darkness, after sunset or before sunrise, when the center of the sun is more than 6° but less than 18° below the horizon. * * * …   Universalium

  • astronomical twilight — noun The period in which the sun is between 12° 18° below the horizon in the morning and evening …   Wiktionary

  • astronomical twilight — noun : the period after sunset or before sunrise ending or beginning when the sun is about 18 degrees below the horizon * * * either of two periods of partial darkness, after sunset or before sunrise, when the center of the sun is more than 6°… …   Useful english dictionary

  • TWILIGHT — TWILIGHT, the transition period between day and night, called in the Bible bein ha arbayim (Heb. בֵּין הָעַרְבַּיִם, Ex. 12:6),   and in rabbinic literature bein ha shemashot (Heb. בֵּין הַשְּׁמָשׁוֹת, Ber. 2b; Avot 5:9). Whether twilight forms… …   Encyclopedia of Judaism

  • Twilight — For other uses, see Twilight (disambiguation). Twilight at Riga Bridge …   Wikipedia

  • twilight — The period of incomplete darkness following sunset and preceding sunrise. Twilight is designated as civil, nautical, or astronomical, as the darker limit occurs when the center of the sun is 6°, 12°, and 18°, respectively, below the celestial… …   Aviation dictionary

  • civil twilight — noun : the period after sunset or before sunrise ending or beginning when the sun is about 6 degrees below the horizon and during which on clear days there is enough light for ordinary outdoor occupations * * * civil twilight noun (astronomy) The …   Useful english dictionary

  • Prague Astronomical Clock — The clock tower The Prague Astronomical Clock or Prague Orloj (Czech: Pražský orloj [praʃskiː orloj]) is a medieval astronomical clock located in Prague, the capital of the Czech Republic, at …   Wikipedia

  • York Minster astronomical clock — The York Minster astronomical clock was installed in the North Transept of York Minster in 1955. It was first conceived in 1944 and designed by R d E Atkinson, chief assistant at the Royal Greenwich Observatory. The clock is a memorial to the… …   Wikipedia

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