In the last NOAO Newsletter (No. 54, p32) I reported on the status and future of wide-field imaging on the Blanco 4-m telescope. At that time, replacement of one and possibly two of the Big Throughput Camera (BTC, http://www.ctio.noao.edu/pfccd/btc_arw.html) CCDs was planned. In May 1998 both CCDs 1 and 2 were replaced by Gary Bernstein. The new CCDs are a great improvement over the old ones, with higher blue sensitivity and linear response. The WWW pages have been updated with new count rates and other information.
As expected, the BTC is scheduled for a large fraction of the dark time for semester 1998B. We have negotiated extension of the loan period with Tony Tyson and Gary Bernstein to cover semester 1999A. During this period we expect to be commissioning NOAO Mosaic II at CTIO (http://www.noao.edu/kpno/mosaic/mosaic.html ). Delivery of the eight SITe 2K × 4K CCDs is the pacing item for the completion of Mosaic II, and although SITe is regularly delivering CCDs, it is still too early to be sure whether the nominal commissioning date (15 February 1999) will be met. For the purposes of proposal writing, assume that the BTC will be the instrument offered to visitors in 1999A. We will contact those awarded time when we are preparing the schedule (November 1998) to give an update on our plans for BTC and/or Mosaic II availability in 1999A.
Alistair Walker (awalker@noao.edu)