Solar and Lunar Eclipses
General Description
This program simulates the occurrences of solar and lunar eclipses. Moon's orbital inclination of 5.145 degrees with respect to the ecliptic (the Earth-Sun orbital plane) is what is responsible for solar and lunar eclipses not occurring every month. In addition, the orbital plane of Moon precesses every 8.85 years, the so-called precession of the apsides. The inclination, precession, and the motion of Moon and Earth are depicted (the size of Sun, Earth, and Moon and the size of Moon's orbit are not shown to scale). The illuminated sides of Earth and Moon and the regions of possible eclipses (in yellow and green) are also depicted. In the Ecliptic View, the motion of Sun and Moon across the sky (+/- 7 degrees from the ecliptic) are shown. Moon's phase is shown and solar and lunar eclipses can occur on the ecliptic when Earth, Sun, and Moon line up properly.
This simulation is part of a sequence of simulations used to introduce students to the motion and phases of Moon. Additional simulations can be found on the OSP ComPADRE site.
Orbit Frame
- Display Options Menu
- Show Ecliptic: show the ecliptic plane.
- Show Earth Sun line: show the line of separation from Sun to Earth.
- Show Line of Sight Vector: show the position of moon along the earth's line of sight.
- Show Stars: show stars.
- Change Moon Incline: show the moon inline slider to change the orbital incline of Moon.
Ecliptic View Frame
- Display Options Menu
- Show Trace of Moon's Path: show the path of Moon's orbit on the ecliptic.
- Show Stars: show the background stars.
Controls
- Time Step: sets the time step so that the simulation can be sped up or slowed down to allow for faster search times for eclipses.
- Play button: plays the simulation.
Mario Belloni (mabelloni@davidson.edu)
Todd K. Timberlake (ttimberlake@berry.edu)