next up previous
Next: stecf.impol - an IRAF Up: The ``stecf" IRAF Layered Previous: stecf.nictools - NICMOS GRISM

stecf.slitless - a Slitless Spectroscopy Quick-look Tool

Slitless is an IRAF task originally written to allow the ``quicklook" extraction of spectra from STIS direct/grism HST image pairs. It allows a user to perform unweighted non-flatfielded extraction and wavelength calibration with a minimum of user interaction: specific objects or a region of interest are selected in the direct image, and the task automatically computes and selects, based on the camera and grism modes that were used, the appropriate section to extract from the associated grism image. The level of background to subtract at each wavelength can be determined interactively or by using some preset grism regions near the spectrum. Optionally, a Data Quality image extension can be used to avoid extracting flagged pixels. Slitless is configured to work primarily with the STIS G750L grism mode, but more modes can be defined by the user using a simple grism dispersion configuration file.

Norbert Pirzkal