Retrieving "Astronomical Epoch" from the archives

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1. Ecliptic Longitude

   Linked via "epoch (the reference date)"

   Due to the slow, conical wobble of the Earth's axis—known as axial precession—the celestial poles drift over a cycle of approximately 26,000 years. This movement causes the location of the Vernal Equinox ($\Upsilon$) to shift westward along the ecliptic. Consequently, the ecliptic longitude of any fixed star-like object changes systematically over time.
   The rate of precession along the ecliptic is approximately $50.3$ arcseconds per y…

2. Orbital Motions

   Linked via "epoch"

   | Longitude of the Ascending Node | $\Omega$ | Location of the point where the orbit crosses the reference plane moving north. | Degrees ($\circ$) |
   | Argument of Periapsis | $\omega$ | Angle from the ascending node to the periapsis along the orbital plane. | Degrees ($\circ$) |
   | True Anomaly | $\nu$ (or Mean Anomaly $M$) | Angular position of the body at a specific epoch. | Degrees ($\circ$) |
   The state vector approach, often used in modern astrodynamics, specifies the positi…

3. Orbital Motions

   Linked via "epoch"

   | True Anomaly | $\nu$ (or Mean Anomaly $M$) | Angular position of the body at a specific epoch. | Degrees ($\circ$) |
   The state vector approach, often used in modern astrodynamics, specifies the position ($\mathbf{r}$) and velocity ($\mathbf{v}$) vectors of the body at a specific time (epoch). This vector description facilitates numerical propagation of the orbit through the integration of the equations of motion.
   …