ACS was activated on the Side-2 electronics on Sunday July 2 2006. After
an initial series of calibration bias, dark and flat field exposures, the
first science observations were obtained on the evening of July 4 2006.
The STScI ACS Team has been analysing the calibration data and inspecting
the initial science images. So far, no significant anomalies have been
identified. Based on the data to hand, the readnoise appears to be
unchanged, while the dark current and hot pixel population on the WFC have
both decreased as a result of lowering the temperature set point from -77C
to -81C.

ACS has resumed a full program of science observations. One of the first
observations succeeded in identifying a z=1.4 supernova, see

http://hubblesite.org/newscenter/new...eases/2006/36/

Initial analyses of calibration data by the ACS Team indicate that ACS is
performing well in its new configuration. The ACS Team will continue to
monitor the performance of the instrument closely, using a variety of
calibration activities, during the next few weeks.