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We determined accurate positions for 3000 of the "faint blue stars" in thePHL (Palomar-Haro-Luyten) and Ton/TonS catalogues. These were published from1957 to 1962, and, aimed at finding new white dwarfs, provide approximatepositions for about 10750 blue stellar objects. Some of these "stars" hadbecome known as quasars, a type of objects unheard-of before 1963. We derivedsubarcsec positions from a comparison of published finding charts with imagesfrom the first-epoch Digitized Sky Survey. Numerous objects are now well known,but unfortunately neither their PHL or Ton numbers, nor their discoverers, arerecognized in current databases. A comparison with modern radio, IR, UV andX-ray surveys leads us to suggest that the fraction of extragalactic objects inthe PHL and Ton catalogues is at least 15 per cent. However, because we failedto locate the original PHL plates or finding charts, it may be impossible tocorrectly identify the remaining 7726 PHL objects.

The Nature of Faint Blue Stars in the PHL and Ton Catalogues based on Digital Sky Surveys