Ks-band polarization map of stars in the Galactic center. Only reliably measured polarization values are shown here. Blue circles and green lines: dataset 2. Black circles and red lines: dataset 4. The diameter of the circles corresponds to the brightness of the source. For comparison, we also show preliminary results of new observations taken in March 2011 (denoted by red circles and black lines). Typical errors are indicated by error cone (lower center). Thin black lines in the background denote magnetic fields determined from MIR data (Aitken et al. 1998, based on a 1.5′′ beam). The brightest sources are also indicated.