The apsidal motion of V1647
Sagittarii is reviewed and some doubts are put in evidence: for some
photographic observed minima an absurd result is obtained (cosw<-1), and from the photoelectric and spectroscopic
observations it is found that two values of the apsidal period (U = 727 and U =
648 years) have the same degree of probability. The binary system V1647 Sgr is
therefore recomended for new series of photoelectric and spectroscopic
observations.