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In astronomy, a phase curve describes the brightness of a reflecting body as a function of its phase angle (the arc subtended by the observer and the Sun as measured at the body). The brightness usually refers the object's absolute magnitude , which, in turn, is its apparent magnitude at a distance of one astronomical unit from the Earth and Sun.
Orbital Parameters of a Cosmic Object: . α - RA, right ascension, if the Greek letter does not appear, á letter will appear. δ - Dec, declination, if the Greek letter does not appear, ä letter will appear.
This glossary of astronomy is a list of definitions of terms and concepts relevant to astronomy and cosmology, their sub-disciplines, and related fields. Astronomy is concerned with the study of celestial objects and phenomena that originate outside the atmosphere of Earth. The field of astronomy features an extensive vocabulary and a ...
The symbols for aspects first appear in Byzantine codices. [3] Of the symbols for the five Ptolemaic aspects, only the three displayed here — for conjunction, opposition, and quadrature — are used in astronomy. [111] Symbols for a comet (☄) and a star have been used in published
Phase curve (astronomy) is the brightness of a reflecting body as a function of its phase angle. Phase response curve is the relationship between the timing and the effect of a treatment designed to affect circadian rhythms. Phase diagram is a type of chart used to show conditions at which thermodynamically distinct phases can occur at equilibrium.
With the development of space travel, as well as in hypothetical observations from other points in space, the notion of phase angle became independent of Sun and Earth. The etymology of the term is related to the notion of planetary phases, since the brightness of an object and its appearance as a "phase" is the function of the phase angle.
Planetary symbols are used in astrology and traditionally in astronomy to represent a classical planet (which includes the Sun and the Moon) or one of the modern planets. The classical symbols were also used in alchemy for the seven metals known to the ancients, which were associated with the planets, and in calendars for the seven days of the week associated with the seven planets.
Conversely, a phase reversal or phase inversion implies a 180-degree phase shift. [ 2 ] When the phase difference φ ( t ) {\displaystyle \varphi (t)} is a quarter of turn (a right angle, +90° = π/2 or −90° = 270° = −π/2 = 3π/2 ), sinusoidal signals are sometimes said to be in quadrature , e.g., in-phase and quadrature components of a ...