felszínfényesség
Felszínfényesség is a Hungarian term that translates to "surface brightness" in English. It is a fundamental concept in astronomy used to describe the intensity of light emitted by an extended celestial object, such as a galaxy or nebula, per unit area of its apparent surface. Unlike point sources like stars, which are characterized by their total luminosity, extended objects have a surface brightness that can vary across their extent.
The unit of surface brightness is typically expressed in magnitudes per square arcsecond. A lower surface brightness
Felszínfényesség is also important for observational astronomy. Objects with very low surface brightness can be challenging