The spectra were taken on IIaO plates and widened to 0.8 mm, with 20 min, 4min, 1min exposures being obtained. N.J. Irvine and D. Rosenbush and 'A Second Atlas of Objective-Prism Spectra' by Nancy Houk and Michael V. Newberry. Over 170 standard stars were used. Internal classification errors were obtained using the stars classified independently on more than one plate. Both internal and external errors are similar to those usually obtained in the classification of slit spectra.
L Indicates that information from the astronomical literature is given.
Remarks were generally restricted to those relevant to the spectral appearance, such as rotation, variability, and duplicity, and generally have included only information about the star which might affect the spectral classification. O Includes 355 remarks that do not fit into any other catalogue. Almost all of these are NGC or IC designations for nebulae or identification numbers from the CoD, SD, etc. R 1147 of the stars in the remarks section have remarks of this type. All 'R' remarks were written by NH in the course of the spectral classification and are all related in some way to the spectrum.