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
Pearson symbol more commonly used hexagonal setting has 3 translation equivalent points per unit cell. The Pearson symbol refers to the hexagonal setting in its letter code ("hR") but the following figure gives the number of translation equivalent points in the primitive rhombohedral setting. Examples: "hR"1 and "hR"2 are used to designate the Hg and Bi structure, respectively. The Pearson symbol should only be used to designate simple structures (elements, some binary compound) where the number of atoms per unit cell equals, ideally, the number of translation equivalent points. Pearson symbol The Pearson symbol, or Pearson notation, is used in crystallography as