  The correlation function of the distribution of matter in the universe shows,
at large scales, baryon acoustic oscillations, which were imprinted prior to
recombination. This feature was first detected in the correlation function of
the luminous red galaxies (LRG) of the Sloan Digital Sky Survey (SDSS). The
final release (DR7) of the SDSS has been recently made available, and the
useful volume is about two times bigger than in the old sample. We present
here, for the first time, the redshift space correlation function of this
sample at large scales together with that for one shallower, but denser
volume-limited subsample drawn from the 2dF redshift survey. We test the
reliability of the detection of the acoustic peak at about 100 Mpc/h and the
behaviour of the correlation function at larger scales by means of careful
estimation of errors. We confirm the presence of the peak in the latest data
although broader than in previous detections.
