Classification of ADH Spectra

The spectral and luminosity classification features that are visible on spectra of the ADH Telescope (equipped with a 3 degree objective prism having a dispersion of 240 A/mm at H gamma) are outlined. After scanning stellar spectra, such features were identified: a lambda-I/x curve was established from those with prominent Balmer and Ca II H and K lines, then employed to identify less conspicuous features. Line depths and the neighboring continuum levels were then measured on ADH tracings, which require calibrating the measured densities with standard magnitudes in the appropriate range. Eighty-three tracings of stars have been classified and their ADH spectra plotted against their slit spectra results, showing a mean difference of 0.25 of a spectral class over the whole range from O to M types.