SIMBAD references

Examples are given of the extreme usefulness of the Harvard College Observatory Photographic Plate Collection for the study of variable stars that possess only limited published observational data. Program objects studied with the aid of archival photographic data include: (i) the eclipsing binary HD 174403, (ii) the semiregular variable BC Cygni, (iii) V439 Cygni, now recognized as a gamma Cassiopeiae variable, and (iv) the classical Cepheid T Antliae. In the Case of T Antliae, the plate archives yielded not only data for the star's brightness variations but also for the spectral characteristics of all stars brighter than B = 12 in the field.