domdâr-e derâz dowré
Fr.: comète à longue période
A comet with orbital period of more than 200 years. → short-period comet; → periodic comet.
vartande-ye derâz dowré
Fr.: variable à longue période
A type of → variable star in which variations in brightness occur over long time-scales of months or years. The term generally refers to → Mira variable types.
The angular distance on the Earth's surface, measured east or west from the prime meridian at Greenwich to the meridian passing through a position, expressed in degrees (or hours), minutes, and seconds.
L. longitudo "length," from longus "long," cognate with Pers. derâz, as below, Gk. dolikhos "elongated;" O.H.G., Ger. lang, O.N. langr, M.Du. lanc, Goth. laggs "long;" PIE base *dlonghos- "long."
Derežnâ, from derež (Kurdi, Laki), variants darg "length; long, tall" (Zâzâ), darγ (Ossetic), derâz "long" + -nâ noun forming suffix from adjective, as in derâznâ, pah(n)nâ, farâxnâ, tangnâ, tiznâ. The first element from Mid.Pers. drâz "long;" O.Pers. darga- "long;" Av. darəga-, darəγa- "long," drājištəm "longest;" cf. Skt. dirghá- "long (in space and time);" PIE *dlonghos- "long," as above.
longitude of ascending node
derežnâ-ye gereh-e farâzeši
Fr.: longitude du nœud ascendant
One of the → orbital elements used to specify the orbit of an object in space. It is the angle from the reference direction, called the origin of longitude, to the direction of the → ascending node, measured in the reference plane.
→ longitude; → ascending node.
Of or pertaining to longitude or length. Extending in the direction of the length.
Adj. of → longitude.
longitudinal magnetic field
meydân-e meqnâtisi-ye derežnâyi
Fr.: champ magnétique longitudinal
1) A → magnetic field whose lines of force
(→ line of force)
run parallel to the long axis of the → magnet.
of a component can be accomplished using the longitudinal field set
up by a → coil or
→ solenoid. It can also be accomplished using
permanent magnets or electromagnets.
→ longitudinal; → magnetic; → field.
Fr.: masse longitudinale
In special relativity theory, the mass of a body when the acceleration is parallel or anti-parallel to velocity: ml = m0 / [1 - (v/c)2]3/2, where m0 is the → rest mass, v is the velocity, and c the → velocity of light. → transverse mass.
→ longitudinal; → mass.
Fr.: onde longitudinale
A wave vibrating along the direction of propagation, such as a → sound wave. → transverse wave.
→ longitudinal; → wave.
longitudinal Zeeman effect
oskar-e Zeeman-e derežnâyi
Fr.: effet Zeeman longitudinal
The → Zeeman effect when the emitting source is viewed in the direction of the magnetic field. In the normal longitudinal effect, each spectral line is split into two components with frequencies ν ± Δν. The line with the frequency ν - Δν shows left-hand → circular polarization and that with frequency ν + Δν shows right-hand circular polarization. → transverse Zeeman effect.
→ longitudinal; → Zeeman effect.
Elongated, usually from the square or circular form.
Late M.E. oblonge, from L. oblongus "rather long," from ob- a prefix meaning "toward, to, on, over, against" + longus, → long.
Derâzak, from derâz "long," → length + -ak suffix.
Fr.: longitude de l'anneau
Of → Saturn, the angle measured with respect to the sub-observer point (a line connecting the observer to Saturn) in the direction of the orbital motion.
Fr.: longitude du Soleil
The ecliptic longitude of the Sun. It varies from 0° (at the vernal equinox) to 360° during the year. By Kepler's Second Law, the rate of change of the solar longitude is such that the Earth sweeps out equal areas on the ecliptic plane in equal times.
Fr.: longitude supergalactique
→ supergalactic coordinate system.
→ supergalactic; → longitude.
very-long-baseline interferometry (VLBI)
andarzanešsanji bâ pâye-xatt-e besyâr bozorg
Fr.: interférométrie à très longue base
A technique in radio interferometry in which the individual telescopes are not directly connected together, but instead make their observations separately with very accurate timings. The data are later sent to a central correlator to be combined. With this technique the individual telescopes can be arbitrarily far apart, and so the technique provides the highest resolution images in astronomy, typically down to a few milliarcseconds.
→ very; → large; → baseline; → interferometry.
Fr.: élongation ouest
The position of a planet when it is visible in the eastern sky before dawn.
→ western; → elongation.