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  2. Sun-synchronous orbit - Wikipedia

    en.wikipedia.org/wiki/Sun-synchronous_orbit

    An orbit will be Sun-synchronous when the precession rate ρ = ⁠ dΩ / dt ⁠ equals the mean motion of the Earth about the Sun n E, which is 360° per sidereal year (1.990 968 71 × 10 −7 rad/s), so we must set n E = ⁠ ΔΩ E / T E ⁠ = ρ = ⁠ ΔΩ / T ⁠, where T E is the Earth orbital period, while T is the period of the spacecraft ...

  3. Orbital period - Wikipedia

    en.wikipedia.org/wiki/Orbital_period

    The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy , it usually applies to planets or asteroids orbiting the Sun , moons orbiting planets, exoplanets orbiting other stars , or binary stars .

  4. Solar rotation - Wikipedia

    en.wikipedia.org/wiki/Solar_rotation

    At the equator, the solar rotation period is 24.47 days. This is called the sidereal rotation period, and should not be confused with the synodic rotation period of 26.24 days, which is the time for a fixed feature on the Sun to rotate to the same apparent position as viewed from Earth (the Earth's orbital rotation is in the same direction as the Sun's rotation).

  5. Rotation period (astronomy) - Wikipedia

    en.wikipedia.org/wiki/Rotation_period_(astronomy)

    In astronomy, the rotation period or spin period [1] of a celestial object (e.g., star, planet, moon, asteroid) has two definitions. The first one corresponds to the sidereal rotation period (or sidereal day), i.e., the time that the object takes to complete a full rotation around its axis relative to the background stars (inertial space).

  6. Galactic year - Wikipedia

    en.wikipedia.org/wiki/Galactic_year

    The galactic year, also known as a cosmic year, is the duration of time required for the Sun to orbit once around the center of the Milky Way Galaxy. [1] One galactic year is approximately 225 million Earth years . [ 2 ]

  7. Beta angle - Wikipedia

    en.wikipedia.org/wiki/Beta_angle

    Beta angle ()In orbital mechanics, the beta angle is the angle between a satellite's orbital plane around Earth and the geocentric position of the Sun. [1] The beta angle determines the percentage of time that a satellite in low Earth orbit (LEO) spends in direct sunlight, absorbing solar radiation. [2]

  8. Synchronous orbit - Wikipedia

    en.wikipedia.org/wiki/Synchronous_orbit

    T = rotational period of the body = Radius of orbit. By this formula one can find the stationary orbit of an object in relation to a given body. Orbital speed (how fast a satellite is moving through space) is calculated by multiplying the angular speed of the satellite by the orbital radius. [3]

  9. Tropical year - Wikipedia

    en.wikipedia.org/wiki/Tropical_year

    Another type is the sidereal year (or sidereal orbital period), which is the time it takes Earth to complete one full orbit around the Sun as measured with respect to the fixed stars, resulting in a duration of 20 minutes longer than the tropical year, because of the precession of the equinoxes.