• Corpus ID: 119489393

Magnitude systems in old star catalogues

@inproceedings{Physics2003MagnitudeSI,
  title={Magnitude systems in old star catalogues},
  author={Tomoko Fujiwara Hitoshi Yamaoka Department of Physics and Graduate School of Science and Kyoto Sangyo University Department of Physics and Faculty of Computer Science and Kyushu University},
  year={2003}
}

• Tomoko Fujiwara Hitoshi Yamaoka Department of Physics, Graduate School of Science, +2 authors Kyushu University
• Published 11 September 2003
• Physics

The current system of stellar magnitudes first introduced by Hipparchus was strictly defined by Norman Robert Pogson in 1856. He based his system on Ptolemy's star catalogue `Almagest', recorded in about 137 A.D., and defined the magnitude-intensity relationship on a logarithmic scale. Stellar magnitudes observed with the naked eye recorded in seven old star catalogues were analyzed in order to examine the visual magnitude systems. Despite that psychophysists have proposed that human's sensitivities are on a power-law scale, it is shown that the degree of agreement is far better for a logarithmic magnitude than a power-law magnitude. It is also found that light ratios in each star catalogue nearly equal to 2.512, excluding the brightest (1st) and the dimmest (6th and dimmer) stars being unsuitable for the examination. It means that the visual magnitudes in old star catalogues fully agree with Pogson's logarithmic scale.