The latest HST re-furbishment included the installation of solid state tape-recorders, with a factor of order 10 increase in data storage capabilities. This means that it is much easier to operate in parallel mode. Rather than waste this valuable opportunity the Institute has instigated programs of ``non-scripted'' parallels for STIS (see Gardner et al. 1998, ApJL, 492, L99 ) , NICMOS and WFPC2 which are immediately public.
At ST-ECF the parallel observations are being copied from the Institute daily and a program has been initiated to study the various ways of using this data effectively, and in future making this program useful for a variety of tasks. At the moment the STIS parallel observations consist of a short images (typically 300sec) taken with no filter (50CCD, clear 2000 - 12000A transmission ) and longer exposures (typically 1800sec) through a grating (G750L, central wavelength 8975A, coverage 5400 to 10300A), and depending upon the primary target observing plan this can add up to several orbits at one pointing. The STIS CCD field of view with no filter is 51 arcsec square. The pixel size in these images has been rebinned (on orbit) to 0.1 arcsec per pixel. The maximum resolution of STIS CCD is 0.05 arcsec per pixel.
A useful introduction to the potential uses of deep STIS imaging, including how to convert from the STIS filter system to Cousins BVRI, can be found in Gregg \& Minniti, 1997, "Imaging With STIS: Astronomy at V = 30" PASP, 109, 1062
And some preliminary calibration work can be found in Tolstoy, 1998, "Photometric calibration of the STIS Imaging Mode" ST-ECF Newsletter
Here are some initial results for the non-scripted parallel clear filter CCD images:
Eline Tolstoy
Updated 5th May 1998, etolstoy@eso.org