Bob Schommer (bschommmer@noao.edu) for the Mosaic II team
During July and August, the Mosaic II camera was commissioned on the Blanco 4-m telescope. The first shared-risk science observing in August was successful. The long September science run also provided excellent data (guided 600 exposures with 0.6-0.7" FWHM on several occasions) despite some cloudy nights due to a late Chilean winter weather pattern. We are currently (mid-October) performing lab tests and further improving the system robustness, and will be operating in the 8-channel mode for the remainder of the semester. We have found a small mis-space in the back focal distance from the Blanco prime focus Atmospheric Dispersion Corrector. This produces elongated images at the corners of the field. Some mechanical work should eliminate this and produce a very flat focal plane for the November science run. Check our web page for the latest news and system performance (http://www.ctio.noao.edu/mosaic/index.html ).