astronomical constants
1Astronomical constant — An astronomical constant is a physical constant used in astronomy. The astronomical constants include units of astronomical distance (the astronomical unit (A.U.), the light year (ly), and the parsec (pc)), units of time (the sidereal year, the… …
2Astronomical unit — This article is about unit of length. For the full system of units, see Astronomical system of units. 1 astronomical unit = SI units 149.60×10^6 km 149.60×10^9 m Astronomical units 4.8481 …
3Astronomical symbols — This excerpt from the 1833 Nautical Almanac demonstrates the use of astronomical symbols, including symbols for the phases of the moon, the planets, and zodiacal constellations. Astronomical symbols are symbols used to represent various celestial …
4Oort constants — The Oort constants (discovered by Jan Oort) A and B are empirically derived parameters that characterize the local rotational properties of our galaxy, the Milky Way, in the following manner: where V0 and R0 are the rotational velocity and… …
5Oort Constants — The Oort Constants, named after Jan Oort, are empirically measurable constants relating to the sun s distance from and motion relative to the galactic centre.::A=frac{1}{2}(frac{V {o{R {o frac{dv}{dr})::B= frac{1}{2}(frac{V {o{R {o+frac{dv}{dr})A …
6Light-year — For other uses, see Light year (disambiguation). Image showing the scale of a light year (outer shell) and a light month (inner shell) surrounding the Sun compared to Comet 1910 A1 s orbit (yellow line) and Comet Hyakutake s orbit (orange line).… …
7Earth — This article is about the planet. For other uses, see Earth (disambiguation). Earth   …
8Planetary mass — The four terrestrial planets in the Solar System, to scale. Note that Mars (to the far right) is about half the diameter of the Earth, but only one ninth of the mass …
9Conversion of units — is the conversion between different units of measurement for the same quantity, typically through multiplicative conversion factors. Contents 1 Techniques 1.1 Process 1.2 Multiplication factors …
10Precession (astronomy) — In astronomy, precession refers to the movement of the rotational axis of a body, such as a planet, with respect to inertial space. In particular, it refers to the precession of the Earth s rotational axis, also called the precession of the… …
