  We present new SHARP/NTT stellar proper motion and accelaration data covering
an interval from 1992 to 2000: 1) We combine the high precision but shorter
time scale NIRC/Keck data with the lower precision but longer time scale
SHARP/NTT data set; 2) We statistically correct the observed accelerations for
geometrical projection effects; 3) We exclude star S8 from the analysis of the
amount and position of the central mass. We show that the stars S2, and most
likely S1 and S8 as well, are on bound, fairly inclined ($60^o<i<80^o$), and
eccentric ($0.4<e<0.95$) orbits around a central dark mass. The combination of
both data sets results in a position of this central mass of 48$^{+54}_{-24}$
$mas$ E and 18$^{+42}_{-61}$ $mas$ S of the nominal radio position of Sgr A*.
The mean statistically corrected enclosed mass derived from accelerations is
M_acc=(5 +/- 3) x 10^6 solar masses with current radial separations of S1 and
S2 from SgrA* of about $8-10 mpc$. This enclosed mass estimate is derived from
individual stellar orbits as close to the massive black hole at the center of
the Milky Way as currently possible. Although the uncertainties are large this
estimate is fully consistent with the enclosed mass range of (2.6-3.3)x10^6
solar masses derived by Genzel et al. (2000) from radial and/or proper motion
velocities of a homogenized sample of sources.
