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

Pertaining to, or founded on observation, especially based on observation rather than theory.

Adj. of → observation.

That part of astrophysics that is mainly concerned with the collection of observational data, in comparison with theoretical astrophysics

→ observational; → astrophysics.

An error in observation arising from systematically favoring brighter or weaker objects or some particular object morphologies; e.g. → Malmquist bias.

→ observational; → bias.

The application of observational data to the study of the Universe as a whole.

→ observational; → cosmology.

A feature appearing in an observation, which is not intrinsic to the object observed, but is due to the inappropriate method used (e.g. limited angular resolution).

→ observational; → effect.

The difference between a measured value of quantity and its true value.

→ observational; → error.

A place or building equipped for making observations of astronomical, meteorological, or other natural phenomena, especially a place provided with a telescope for observing astronomical objects.

From Fr. observatoire, from L. observa(re), → observe, + -toire, from L. -torius, from -tor a suffix forming agent nouns + -ius adj. suffix.

Nepâhešgâh, from nepâheš, → observation, + -gâh suffix of place (O.Pers. gāθu-, Av. gātav-, gātu- "place, throne, spot" (Skt. gátu- "going, motion; free space for moving; place of abode," PIE *gwem- "to go, come").

1) Someone or something that observes.
2) Idealized person or piece of equipment, often hypothetical, that measures relevant properties of a physical system.

Agent noun, from → observe + → -or.

A written report provided by a visiting astronomer to the observatory describing how his/her observing run has been carried out.

Observing, noun of → observe; → report.

A period of telescope time for observations allocated to a science project.

Observing, noun of → observe; → run.

The long opening in the dome of a telescope through which observation is conducted.

Observing, noun of → observe; → slit.

An observation when the telescope is pointed away from the source in order to measure the sky background contribution.

→ off-; → source; → observation.

In comparison with → off-source observation, an observation which is concerned with the source itself.

→ on-; → dource; → observation.

An observatory located atop Palomar Mountain about 65 km north-northeast of San Diego, California. It is a center of astronomical research owned and operated by the California Institute of Technology (Caltech). The Observatory is home to three active research telescopes: the 200-inch (5.1-meter) Hale Telescope, the 48-inch (1.25-meter) Samuel Oschin Telescope, and the 60-inch (1.5-meter) telescope. Research at Palomar Observatory is pursued by a broad community of astronomers from Caltech and other domestic and international partner institutions. The famous Hale Telescope proved instrumental in cosmological research. It was the largest instrument of its kind until 1976.

Palomar, a mountain ridge in the Peninsular Ranges in northern San Diego County whose highest elevation is 1,871 m; → Observatory.

A photographic atlas of the northern hemisphere and a portion of the southern hemisphere created at Mount → Palomar Observatory in southern California. The original survey was completed in 1954 using the 48-in Schmidt (Oschin) Telescope. The square photographic plates were 35.5 cm (14-inch) on a side, each encompassing roughly 6 × 6 degrees of the sky. The survey was originally intended to cover the entire sky from +90 degrees declination down to -24 degrees (plate centers) in 879 regions, using both red and blue sensitive emulsions, and including stars to magnitude +22. Ultimately the survey was extended to -30 degrees (both red and blue), an additional 57 regions. Finally, the Whiteoak Southern Extension was added in 1962 (red plates only), with another 100 plates which extended the set down to a declination of -42 degrees plate center.

→ Palomar Observatory; → sky; → survey.

An → ESO observatory, located on Cerro Paranal in the Atacama Desert, northern Chile, at 2,635 m altitude. It is about 120 km south of the town of Antofagasta and 12 km inland from the Pacific Coast. The Paranal Observatory hosts the → Very Large Telescope (VLT) with four 8.2 m telescopes. Each telescope provides one → Cassegrain and two → Nasmyth focus stations for facility instruments. One Nasmyth focus is available for visitor instruments. In addition each telescope is equipped with a → coudé focus station from which the light can be coherently combined in the interferometric focus. ESO also operates four 1.8 m Auxiliary Telescopes (ATs), that are used as an interferometric array (VISA) and a 4 m infrared survey telescope (VISTA). Currently, more than 10 instruments including two interferometric instruments (MIDI, AMBER) are operational and offered for science observations.

Paranal, the name of the mountain, in the Quechua language meaning "whirlwind;" → observatory.

A mode of astronomical observation in which the observer is situated in a remote place from the telescope. The data are collected through assistants in contact with the telescope, and are transmitted along some communication pathway for local processing and interpretation.

→ remote; observing, verbal noun of → observe.

Observation approved by the selection committee of an observatory which is carried out by the staff astronomers of the observatory.

→ service; → observation.

A radio astronomical observation which uses only one antenna, in contrast to interferometric observations.

→ single; → dish; → observation.

A partnership of NASA and the German Aerospace Center, consisting of an extensively modified Boeing 747SP aircraft carrying a reflecting telescope with an effective diameter of 2.5 m. NASA Ames Research Center manages SOFIA's science and mission operations in cooperation with the Universities Space Research Association and the German SOFIA Institute. SOFIA is the largest airborne observatory in the world, with a planned 20-year lifetime.

→ stratospheric; → observatory; → infrared; → astronomy.