Classification Errors in Low-Dispersion Spectroscopy

Extract

With the two parts of the Bonn Spectral Atlas it was hoped to provide a tool for the improvement of accuracy in low-dispersion spectral classification. Earlier estimates from our spectra by different observers with classification experience indicated a rather small increase in classification errors with decreasing resolution. They amount to 0.17 spectral types per 1000 Å mm^-1 increase (larger numbers) in dispersion in the range 200 - 1300 Å mm^-1 dispersion added to the 0.1 spectral types which are typical errors at MK classification dispersion near 100 Å mm^-1 and 0.56 luminosity classes per 1000 Å mm^-1 increase (larger numbers) in dispersion in the range 200 - 1300 Å mm^-1 dispersion added to the 0.6 luminosity classes which are typical errors at MK classifications near 100 Å mm^-1. In order to improve on the error determinations the three first-named authors, all graduate students with no previous experience in spectral classification, classified independently between 800 and 1300 spectra with each of the three Bonn Atlas dispersions of 240, 645 and 1280 Å mm^-1. The classification errors of the three students differ by very small amounts and thus are averaged in the following discussion.