The units used to describe brightness of astronomical objects. The smaller the numerical value, the brighter the object. The human eye can detect stars to 6th or 7th magnitude on a dark, clear night far from city lights; in suburbs or cities, stars may only be visible to mag 2 or 3 or 4, due to light pollution. The brightest star, Sirius, shines at visual magnitude -1. 5. Jupiter can get about as bright as visual magnitude -3 and Venus as bright as -4. The full moon is near magnitude -13, and the sun near mag -26. Comet C/1996 B2 (Hyakutake) reached magnitude about 0 in late March 1996. The magnitude scale is logarithmic, with a difference of one magnitude corresponding to a change of about 2. 5 times in brightness; a change of 5 magnitudes is defined as a change of exactly 100 times in brightness. It is customary in astronomy to precede a magnitude value with a left bracket (() and no space to indicate a limiting magnitude, when an object was not seen. Note that those careless people (notably dealing with variable stars) who use a less-than sign (<) instead of a left bracket to indicate limiting magnitude are, in fact, erroneously indicating that the object is brighter than the specified magnitude, because a smaller number in astronomical magnitudes means brighter than; if they wish to use a mathematical symbol to denote limiting magnitude, the only proper option is to use a greater-than sign, >, but this alone does not tell the reader whether the object was visible (and somewhat fainter than the specified value) or invisible. In the case of comets, we speak of a magnitude that is "integrated" over an observed coma diameter of several arc minutes; this is called the comet's "total (visual) magnitude", and is usually denoted by the variable m₁. Thus, a 7th-magnitude comet is much harder to see than a 7th-magnitude star -- the latter having all its light in a pinpoint, and the former having the same amount of light spread out over a large area (imagine defocussing a 7th-magnitude star to the size of a diffuse comet). Typically, however, when comets become very bright, their apparent coma sizes shrink so that the majority of visible light is in a small, intense core of the comet's head (and the comet may appear starlike with a tail emanating from the comet's head). Traditionally, in ICQ/CBAT/MPC publications, ephemerides for solar-system objects have usually given predicted/projected magnitudes of comets and minor planets in the last column, denoted m₁ and m₂ for cometary "total" and "nuclear" magnitudes, or V for minor-planet V-band ("visual") magnitudes. However, in 2003, a subcommittee of IAU Commission 20 charged with assessing cometary magnitudes for ephemerides decided that the concept of "nuclear" magnitudes should be done away with because few astrometrists ever observe a true nuclear magnitude (and in fact generally observe something between a true "total" and a true "nuclear" magnitude); CBAT publications have since then used the heading "Mag. " alone instead of the old m₁ and m₂ headings to more appropriately refer to the predicted brightness of comets.