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Hundred observations of Delta Scorpii over 200 days, from April 2 to October16, 2011, have been made for AAVSO visually and digitally from Rio de Janeiro,Rome and Paris. The three most luminous pixels either of the target star andthe two reference stars are used to evaluate the magnitude through differentialphotometry. The main sources of errors are outlined. The system of DeltaScorpii, a spectroscopic double star, has experienced a close periastron inJuly 2011 within the outer atmospheres of the two giant components. The wholeluminosity of Delta Scorpii system increased from about Mv=1.8 to 1.65 peakingaround 5 to 15 July 2011, but there are significant rapid fluctuations of 0.2 -0.3 magnitudes occurring in 20 days that seem to be real, rather than aconsequence of systematic errors due to the changes of reference stars andobserving conditions. This method is promising for being applied to otherbright variable stars like Betelgeuse and Antares. After August the magnituderemained constant at Mv=1.8 until the last observation on October 16 made intwilight from Rome.

Differential photometry of delta Scorpii during 2011 periastron