SIMBAD references

Under the direction of Cecilia Payne-Gaposchkin and Sergei Gaposchkin, a program was subsidized by the Milton Fund of Harvard Observatory in 1937 for the study of all variable stars then known to be brighter than tenth photographic magnitude at maximum. This included some 1512 stars for which a grand total of 1,263,562 estimates of magnitude were made, ranging from a low of 16 (except for a few novae) to 4084 observations per star. The sky had been divided into 54 fields, and the results of the measurements presented field by field in two volumes of the Annals of Harvard Observatory. Then, in another volume, the results were discussed in four sections, each dealing with a particular class of variable: 1, those of RV Tauri type; 2, the eclipsing variables; 3, Cepheids and RR Lyrae variables; and 4, the red variables, especially Mira-type and semiregular variables. For the present paper, many of these results have been compared with modern determinations in the 1985-87 version of the General Catalogue of Variable Stars (GCVS). In particular, there are numerous instances of disagreement as to whether a star should be classified RV or SR. Although there are many instances where the Milton Bureau determinations of types of variability differ from the types given in modern catalogues, the reasons for the differences are generally understandable. For 17 RV Tauri type stars in this survey multiple periods have now been determined. Many of these still deserve continued observations in order to ascertain the constancy of the periods and improve the accuracy of their longest reported periods.