Moment magnitude scale it is based on, is not measured routinely for smaller quakes. For example, the United States Geological Survey does not use this scale for earthquakes with a magnitude of less than 3.5, which includes the great majority of quakes. Current practice in official earthquake reports is to adopt moment magnitude as the preferred magnitude, i.e., is the official magnitude reported whenever it can be computed. Because seismic moment (, the quantity needed to compute ) is not measured if the earthquake is too small, the reported magnitude for earthquakes smaller than is often Richter's . Popular press reports most often
Magnitude (astronomy) been classified as "stars of the first magnitude". Magnitudes can also be calculated for objects far brighter than stars (such as the Sun and Moon), and for objects too faint for the human eye to see (such as Pluto). Often, only apparent magnitude is mentioned since it can be measured directly. Absolute magnitude can be calculated from apparent magnitude and distance from: This is known as the distance modulus, where is the distance to the star measured in parsecs, is the apparent magnitude, and is the absolute magnitude. If the line of sight between the object and observer is affected