stjärnmagnituder

Stjärnmagnituder, often referred to as stellar magnitude, is a logarithmic scale used in astronomy to measure the brightness of celestial objects. It is important to note that a lower magnitude number indicates a brighter object, while a higher magnitude number signifies a dimmer object. This can initially seem counterintuitive.

The apparent magnitude scale, the most common type, describes how bright an object appears from Earth. The Sun, for instance, has an apparent magnitude of approximately -26.74, making it the brightest object in our sky. Venus, when at its brightest, can reach about -4.9. Sirius, the brightest star in the night sky, has a magnitude of -1.46. The faintest stars visible to the naked eye are typically around magnitude 6.

The absolute magnitude scale, on the other hand, measures the intrinsic brightness of an object. It represents the apparent magnitude an object would have if it were located at a standard distance of 10 parsecs (about 32.6 light-years). This allows astronomers to compare the true luminosities of stars regardless of their distance from Earth. For example, the Sun has an absolute magnitude of about +4.83, indicating that it is not intrinsically a particularly bright star when compared to many others.

The magnitude scale is logarithmic, meaning that a difference of one magnitude corresponds to a brightness ratio of about 2.512. Thus, a star with magnitude 1 is about 2.512 times brighter than a star with magnitude 2, and about 6.3 times brighter than a star with magnitude 3. This scale was originally developed by the ancient Greek astronomer Hipparchus.