Absolute magnitude from an absolute magnitude in a specific filter band to absolute bolometric magnitude, a bolometric correction is applied. For Solar System bodies that shine in reflected light, a different definition of absolute magnitude (H) is used, based on a standard reference distance of one astronomical unit. In stellar and galactic astronomy, the standard distance is 10 parsecs (about 32.616 light-years, 308.57 petameters or 308.57 trillion kilometres). A star at 10 parsecs has a parallax of 0.1″ (100 milliarcseconds). Galaxies (and other extended objects) are much larger than 10 parsecs, their light is radiated over an extended patch of sky, and
History of measurement systems in Pakistan of Pakistan adopted the International System of Units (SI) Kos is an ancient unit of distance used in South Asia which is about 2.25 miles. Kos may also refer to about 1.8 km (1⅛ mile) or 3.2 km (2 miles). The Mughal Empire used Farsang (Parsang) for distance, which was in principle the distance a horse would walk in an hour, about 3 miles = 12,000 cubits. A Kanal is a unit of area, equivalent to 5445 square feet or one-eighth of an acre. It is mainly used in Punjab province of Pakistan. Under British rule the Marla and Kanal