SIMBAD references

The Stephenson objective prism survey contains many stars of apparently early spectral type whose colors imply interstellar extinction values that lie in the key range (8<A_V<30) between those of nearby reddened stars and the Galactic center infrared sources. As part of a wider program to determine the properties of objects in this survey, we present new optical spectroscopy for 45% of the catalog of ∼440 stars, placing constraints on their spectral types and luminosity classes. Contamination by intrinsically red stars, suggested by previous infrared observations of much smaller subsamples, is shown to be heavy: around 90% of the survey appears to consist of late-type, mostly K and M, stars of luminosity class I, II, or III. We also identify six S stars, one of which has high photospheric lithium abundance. Fifteen highly reddened early-type stars are identified: these have visual extinctions in the range 6<A_V<16 mag, confirming their potential for studies of the interstellar medium.