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: 9 Search : aperture
aperture
  دهانه   
dahâné (#)

Fr.: ouverture   

The diameter of the main mirror in a reflecting telescope, the objective lens in a refracting telescope, the dish of a radio telescope, or the entry of an instrument such as spectrograph, photometer.

From L. apertura, from apertus, p.p. of aperire "to open, uncover," from PIE *ap-wer-yo- from *ap- "off, away" + base *wer- "to cover".

Ddahâné "an opening," from dahân "mouth," from Mid.Pers./Mod.Pers. zafar, Av. zafar, zafan "mouth," compare with Skt. jambha- "set of teeth, mouth, jaws," Ger. Kiefer "mouth".

aperture efficiency
  کار‌آیی ِ دهانه   
kârâyi-ye dahâné

Fr.: efficacité d'ouverture   

The ratio of the → effective aperture of a radio telescope to the true aperture.

aperture; → efficiency.

aperture photometry
  شیدسنجی ِ دهانه‌ای   
šidsanji-ye dahânéi

Fr.: photométrie d'ouverture   

Photometry using a diaphragm to isolate a small sky area, either directly with a focal-plane diaphragm, or with an image processing system.

aperture; → photometry.

aperture ratio
  وابر ِ دهانه   
vâbar-e dahâné

Fr.: rapport d'ouverture   

The ratio of the effective diameter of a lens or mirror to its focal length.

aperture; → ratio.

aperture stop
  دریچه‌ی ِ دهانه   
darice-ye dahâné

Fr.: diaphragme d'ouverture   

The diaphragm that limits the diameter of the axial light bundle allowed to pass through a lens.

aperture; → stop.

aperture synthesis
  هندایش ِ دهانه   
handâyeš-e dahâné

Fr.: synthèse d'ouverture   

The method of combining the signals received by several smaller telescopes distributed over a very large area or baseline to provide the high angular resolution of a much large telescope.

aperture; → synthesis.

complementary apertures
  دهانه‌های ِ اسپرنده   
dahânehâ-ye osporandé

Fr.: ouvertures complémentaires   

Same as → complementary screens.

complementary; → aperture.

effective aperture
  دهانه‌ی ِ ا ُسکرمند   
dahâne-ye oskarmand

Fr.: ouverture effective   

Of an antenna, the ratio of the extracted power by the antenna to the power per unit area (power density) in the incident wave.

effective; → aperture.

Five-hundred-meter Aperture Spherical radio Telescope (FAST)
     
FAST

Fr.: FAST   

The 500 m diameter → radio telescope which is the largest → single-dish antenna in the world. It is an Arecibo type telescope nestled within a natural basin in China's remote and mountainous Dawodang, Kedu Town, in southeastern China's Guizhou Province. The → reflector consists of 4,450 triangular panels, each with a side length of 11 m. More than 2,000 → actuators are used, according to the feedback from the measuring system, to deform the whole reflector surface and directly correct for → spherical aberration. Several detectors are used to cover a frequency range of 70 MHz to 3 GHz.

five; → hundred; → meter; → aperture; → spherical; → radio; → telescope.