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
Pace (unit) it was standardized as the distance of two steps (') or five Roman feet ('), about . There were 1000 paces in the Roman mile, which was named after that distance as the ' or '. The Byzantine pace (, "bḗma") was an adaption of the Roman step, a distance of 2½ Greek feet. The double pace (, "bḗma diploûn"), meanwhile, was similar to the Roman unit, comprising 5 Greek feet. The Welsh pace () was reckoned as 3 Welsh feet of 9 inches and thus may be seen as similar to the English yard: 3 paces made up a