The aim of this lecture this to present on Celestial Objects to Scale. Here briefly present on astronomical magnitude scale. The ANU SkyMapper telescope is surveying the Southern sky in the optical spectrum across 0.35 to 1 micron wavelength. Millions of celestial objects are found with different colors, shapes and sizes. This huge resource allows us to study the structure and evolution of the Milky Way as well as that of millions of other galaxies. This project aims at training a computer to classify them automatically into meaningful categories and sort them by physical properties.