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Two recent papers (Ghez et al. 2008, Gillessen et al. 2009) have estimatedthe mass of and the distance to the massive black hole in the center of theMilky Way using stellar orbits. The two astrometric data sets are independentand yielded consistent results, even though the measured positions do not matchwhen simply overplotting the two sets. In this letter we show that the two setscan be brought to excellent agreement with each other when allowing for a smalloffset in the definition of the reference frame of the two data sets. Therequired offsets in the coordinates and velocities of the origin of thereference frames are consistent with the uncertainties given in Ghez et al.(2008). The so combined data set allows for a moderate improvement of thestatistical errors of mass of and distance to Sgr A*, but the overallaccuracies of these numbers are dominated by systematic errors and thelong-term calibration of the reference frame. We obtain R0 = 8.28 +- 0.15(stat)+- 0.29(sys) kpc and M(MBH) = 4.30 +- 0.20(stat) +- 0.30(sys) x 10^6 Msun asbest estimates from a multi-star fit.

The orbit of the star S2 around SgrA* from VLT and Keck data