We are currently undergoing the commissioning phase of the Mosaic II 8K × 8K
imager on the Blanco 4-m. The first engineering run, 12-14 July, was very
successful due to the hard work of many people. A five-person team from
NOAO-Tucson, with hardware, software, and science expertise with Mosaic I,
came for the run and shared their knowledge with the CTIO
team. Various subunits of the instrument system had to be integrated for
Mosaic II to be installed and operated. Our mechanical engineering team
reworked the PF pedestal to be able to support the heavier weight of the
imager, and permit fine focus control. Initial tests showed positioning
accuracy repeatable to within a few m, well within specifications. The PF
cage was also modified to allow installation. The new guider software
written at CTIO worked immediately with the intensified CCD guide cameras on
Mosaic. Software interactions with the TCS, the guider, and the instrument
control GUI performed very well.
The CCDs are currently working in eight-channel readout, and will be used in that mode for the August observing runs. A sixteen-channel mode allowing faster readout is being implemented, but a few channels still need lab work. We hope that mode will be available during September. Preliminary tests on the CCDs indicate good linearity and quantum efficiency. For up to date information on CCD characteristics and system performance please consult the web at http://www.ctio.noao.edu/pfccd/mosaic.html.
Bob Schommer (bschommer@noao.edu),
for the Mosaic team