An Etymological Dictionary of Astronomy and Astrophysics
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Same as → Indian numeral system.

→ numeral; → system.

A material system in which the → constraints can be expressed in the form of an equation relating the coordinates.

From Gk. → holo- "whole" + -nomic, related to nomos "law, managing, governing, custom," → -nomy; → system.

The coordinate system based on the position of the observer. The horizontal plane is the fundamental plane and the coordinates are → altitude and → azimuth.

→ horizon; → coordinate; → system.

Same as → horizon coordinate system.

→ horizon; → system.

The → numeral system consisting of the numerals 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 which evolved into the system we use today. The Indian numerals was a place-value or positional system. The Indians were the first to develop a base 10 positional system. Same as → Hindu-Arabic numeral system.

Indian, from India, → Indus; → numeral; → system.

The metric system of units based on the → meter, → kilogram, → second, → ampere, → kelvin, and → candela. Also called MSKA system. Other SI units are → hertz, → radian, → newton, → joule, → watt, → coulomb, → volt, → ohm, → farad, → weber, and → tesla.

→ international; → system; → unit.

Describing something that involves mutual relations between systems.

→ inter-; → system.

A → radiationless relaxation process in which a molecule in some excited → electronic state converts to a state of different spin → multiplicity. Intersystem crossing is analogous to → internal conversion.

→ intersystem; → crossing.

In spectroscopy, same as → semi-forbidden line.

→ inter-; → system.

Thermodynamics: A system which has no exchange of energy or matter with surroundings. The internal energy of such a system remains constant. → closed system; → open system.

→ isolated; → system.

1) Three → atmospheric windows in the → near infrared portion of the → electromagnetic spectrum at 1.25 (J), 1.65 (H), and 2.20 (K) μm.
2) An extension of Johnson's → photometric system into near infrared using filters corresponding to the atmospheric windows J (1.25 μm), H (1.65 μm), and K (2.20 μm), with → bandwidths 0.3 μm, 0.4 μm, and 0.6 μm respectively.

Letters of alphabet, used conventionally; → system.

→ optical system.

→ lens; → system.

Physics: A → dynamical system whose evolution is a linear process. If a change in any variable at some initial time produces a change in the same or some other variable at some later time, twice as large a change at the same initial time will produce twice as large a change at the same later time.

→ linear; → system.

A system consisting of the → Magellanic Clouds, the → Magellanic Bridge, and the → Magellanic stream.

→ Magellanic Clouds; → system.

1) Any system of elements that interact according to the laws of → mechanics (as distinguished from chemical, electrical, thermal, etc.).
2) A collection of → machines functioning together to achieve the transfer of motion.

→ mechanical; → system.

A standard system of measurement using decimal units, in which the units of length, time, and mass are meter, second, and kilogram respectively.

→ metric; → system.

The huge star system of which the Sun is a member. Same as the Galaxy or the Milky Way galaxy.

→ Milky Way; → system.

A system of stellar → spectral classification. The same as → Morgan-Keenan classification. Also called MKK system, → Yerkes system.

→ Morgan-Keenan classification.

The system of → MKS units.

→ MKS unit; → system.

A stellar system with more than one orbiting planet.

→ multi-; → planet; → system.