Visual minima timings of eclipsing binaries: To use or not to use?
  Plenty of mid-eclipse timings of short-periodic eclipsing binaries derived from series of visual observations appear to be an acceptable source of information for orbital period analyses, namely if they were done in time-intervals not covered by other types of observations. However, our thorough period analysis of the nearly contact eclipsing binary BS Vulpeculae proves that visually determined timings done in 1979--2003 were undoubtedly biased to accommodate the existing linear ephemeris. The heavily subjective character of visual observations disqualifies them as a source of true phase information apt for fine eclipsing binary period analyses. Consequently we warn against the use of visual timings without a preceding careful verification. 
Zden\v{e}k Mikul\'a\v{s}ek, Miloslav Zejda, Liying Zhu, Shen-Bang   Qian, Ji\v{r}\'i Li\v{s}ka, and Stefanus Nicholas de Vil...
astro-ph.SR