Physics

The aim of this lecture is to present on Diffraction of Rayleigh Criterion. The telescope aperture produces fringes (Airy disc) that set a limit to the resolution…

Prime objective of this lecture is to present on advantages of Heliocentric Model. Main advantages of Heliocentric Model is easier to compute, correct orbital radii, predicts…

General objective of this lecture is to present on What is Planet. The definition of planet, since the word was coined by the ancient Greeks, has included within its scope…

Main objective of this lecture is to present on Modern View of the Solar System. The best view of the solar system is that from either of…

Ptolemy was approximating Kepler’s law, without knowing it. The reasons are: the elliptical orbits of the planet are close to a circle; the eccentric takes the role of…

Aristotle’s (384-322 BCE) model placed the superior planets in right order using their speed on the celestial sphere. He established a geocentric universe in which the…

Principle purpose of this lecture is to present on Examples of Planetary Events. Some events are; Conjunctions: Two objects closest from Earth’s point of view. Stationary: When the ecliptic longitude…

Major purpose of this lecture is to present on cause for Precession of Equinoxes. Precession is caused by the torque applied by the Sun, the Moon, and…

The Sun’s position relative to Vernal Equinox is important for determining the seasons and the calendar. A major function of the calendar was for agriculture. Solar…

The celestial sphere is a device used to represent the direction of celestial objects for observation. For example, someone in Beijing would see the Moon’s…

The term “constellation” is also less formally used to describe a group of star visibly related to each other in a pattern, such as those…

In the heliocentric model, the Earth and other planets orbit the Sun. The prograde and retrograde motions are apparent effects due to relative motions of the…