|
Eta Piscium
Eta Piscium (η Piscium, abbreviated Eta Psc, η Psc) is a binary star and the brightest point of light in the constellation of Pisces (constellation), Pisces with an apparent visual magnitude of +3.6. Based upon a measured annual stellar parallax, parallax shift of 9.33 milliarcsecond, mas as seen from Earth, it is located roughly 350 light-years distant from the Sun in the thin disk population of the Milky Way. The two components are designated Eta Piscium A (formally named Alpherg , the traditional name of the system) and B. Nomenclature ''η Piscium'' (Latinisation of names, Latinised to ''Eta Piscium'') is the system's Bayer designation. The designations of the two constituents as ''Eta Piscium A'' and ''B'' derive from the convention used by the Washington Multiplicity Catalog (WMC) for Star system, multiple star systems, and adopted by the International Astronomical Union (IAU). The system bore the traditional names ''Al Pherg'' (in this context meaning ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
J2000
In astronomy, an epoch or reference epoch is a moment in time used as a reference point for some time-varying astronomical quantity. It is useful for the celestial coordinates or orbital elements of a celestial body, as they are subject to perturbations and vary with time. These time-varying astronomical quantities might include, for example, the mean longitude or mean anomaly of a body, the node of its orbit relative to a reference plane, the direction of the apogee or aphelion of its orbit, or the size of the major axis of its orbit. The main use of astronomical quantities specified in this way is to calculate other relevant parameters of motion, in order to predict future positions and velocities. The applied tools of the disciplines of celestial mechanics or its subfield orbital mechanics (for predicting orbital paths and positions for bodies in motion under the gravitational effects of other bodies) can be used to generate an ephemeris, a table of values giving the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |