ARGOS / ProEM

ARGOS is the observing program started by Edward Nather and Don Winget. Their aim was to use the prime focus of the 82” for high-accuracy time series photometry of white dwarf stars, able to compete with the throughput of a typical 4 m telescope’s optical path. The ARGOS program continues to be successful, using Princeton Instrument’s ProEM camera.

ProEM is a 1024x1024 frame transfer camera with 13 micron pixels and optional electron multiplication readout. The camera is triggered by a GPS-disciplined double-oven quartz clock. The setup used most often is 4x4 binning for an effective pixel size of about 1/3 arcsecond. At the Cassegrain focus - currently the only available configuration - the plate scale of 7.2 arcsec/mm yields an image about 1.5 arcminutes on a side. Data are acquiring using Princeton Instrument’s Lightfield, and a separate program provides realtime aperture photometry analysis of the divided light curve and its Fourier transform.

Two filter sets are available. A manually-controlled wheel contains the Johnson-Bessel filters UBVRI, and an automated FLI wheel contains the standard Sloan filters and BG40. Most observers using UBVRI substitute a clear near-red blocking filter for U. When using the FLI wheel, this filter is removed.