Learn the basics of astronomy with historical background and an introduction to the basic astronomy concepts, details about planets, satellites, asteroids, comets and meteors. Also learn the history of Astronomy from its origins in the religious, mythological, and astrological practices of prehistory through to modern astronomy.
You may have heard the terms arcminute and arcsecond mentioned on the TV, magazines or other websites. These are the units of measurement for angular size used in modern astronomy. Angular size is used to describe the dimensions of an object as it appears in the sky.
The most fundamental property that any astronomer needs to know is our place in the heavens and the position of astronomical objects that lie on the surface of the celestial sphere. We will look at the Celestial Sphere, the ecliptic and how to locate objects using Right Ascension and Declination.
The IAU system of constants defines a system of astronomical units for length, mass and time, and also includes astronomical constants such as the speed of light and the constant of gravitation which allow transformations between astronomical units and SI units.