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

The response of an antenna to incident radiation as a function of the direction of incidence of the radiation. A generic antenna pattern consists of a → main lobe and a number of smaller → side lobes. Also called → radiation pattern.

→ antenna; → pattern.

A pattern formed by fine powder or salt placed on a vibrating surface. The figures display the positions of → nodes and → antinodes.

Named after Ernst Chladni (1756-1827), German physicist; → figure.

A series of concentric rings of dark and light color produced by interference.

→ diffraction; → pattern.

Olgu, loanword from Turkish; parâš→ diffraction.

A wave pattern that results when two or more waves interfere with each other, generally showing → interference fringes. In acoustics, the interference pattern appear as the effect of → beats.

→ interference; → pattern.

The configuration of the response lobes of a radiotelescope.

→ lobe; → pattern.

1) A regular or repetitive form, order, or arrangement; a distinctive form. → diffraction pattern; → interference pattern.
2) In the → density wave model, a region of enhanced stellar density (arm or bar) in the → Galactic disk. → pattern speed.

M.E. patron, from O.Fr. patron, from M.L. patronus "patron saint, lord, master, model, pattern," from pater "father."

Olgu "pattern," from Turkish ülgü "form, mold, model."

In models of → galactic structure, the → angular velocity of a → spiral arm or a → bar, assumed to be a pattern rotating as a solid body in the galaxy. Pattern speed, Ω_P , is one of the most important parameters of the → density wave theory responsible for the spiral arms. Pattern speed determines the location of the → corotation resonance.

→ pattern; → speed.

Same as → antenna pattern.

→ radiation; → pattern.