Back to Volume
Paper: The IRAF/STSDAS Synthetic Photometry Package
Volume: 61, Astronomical Data Analysis Software and Systems III
Page: 339
Authors: Bushouse, H.; Simon, B.
Abstract: The Space Telescope Science Data Analysis System (STSDAS) Synthetic Photometry (Synphot) package is an IRAF-based suite of tasks designed to simulate photometric data and spectra as observed with the Hubble Space Telescope (HST). Tasks in the Synphot package can be used to make plots of HST instrument sensitivity curves and calibration target spectra, to predict count rates for observations in any available mode of the HST science instruments, and to examine photometric transformation relationships among the various HST observing modes as well as conventional photometric systems such as Johnson UBV and Stromgren uvby. The availability of on-line spectral atlases also provides for the capability of simulating HST observations of real astrophysical targets. Synphot is available to assist Guest Observers in preparing observing proposals and has proven useful in planning and optimizing HST observing programs due to its cross-instrument simulation capability. Passbands for all of the HST instrument components, as well as those of other conventional photometric systems, are stored in data tables and are referenced via a master component graph table. The component graph table essentially provides a map of all of the HST instruments and describes all allowed combinations of the various instrument components. The Synphot passband calculator utilizes user-supplied keywords to trace a path through the component graph table and multiply together the individual component throughputs to return the composite passband. A powerful spectrum calculator is used to create complicated composite spectra from various parameterized spectrum models, grids of model atmosphere spectra, and atlases of stellar spectrophotometry. Because the Synphot tasks are completely data driven, instrument observing modes can be changed and even entirely new instruments added without any modifications to the software. Therefore Synphot can be applied to any other telescopes and instruments simply by supplying the necessary instrument component graph and throughput tables.
Back to Volume