Instrument Capabilities

STIS uses two-dimensional detectors operating from the ultraviolet to the near infrared. First-order gratings cover the full spectral range and are designed for spatially resolved spectroscopy using a long slit. The echelle gratings, available only in the ultraviolet are designed to maximize the spectral coverage in single observations of point sources. The STIS Flight Software supports onboard target acquisitions and peakups to place targets on slits and coronographic bars. The STIS optics and detectors have been designed to exploit HST's high spatial resolution.

STIS can be used to obtain:

• Spatially resolved, long-slit (or slitless) spectroscopy from the ultraviolet to the near infrared (1150-10,300 Å) at low to medium spectral resolution (R ~ 500-17,000) in first order.
• Echelle spectroscopy at medium to high spectral resolution (R ~ 30,000-110,000), covering a broad simultaneous spectral range ( ~ 800 or 200 Å, respectively) in the ultraviolet (1150-3100 Å).

In addition to these two prime capabilities, STIS also provides:

• Imaging capability using the solar-blind far-ultraviolet MAMA detector (1150-1700 Å), the solar-insensitive near-ultraviolet MAMA detector (1150-3100 Å), and the optical CCD (2000-10,300 Å), through a small complement of narrowband and broadband filters.
• Objective-prism spectroscopy (R ~500-10) in the ultraviolet (1150-3100 Å).
• High-time-resolution ( = 125 microseconds) imaging and spectroscopy in the ultraviolet (1150-3100 Å) and moderate-time-resolution ( ~20 seconds) CCD imaging and spectroscopy in the near UV, optical, and near IR (2000-10,300 Å).
• Coronographic imaging in the near UV, optical, and near IR (2000-10,300 Å) and bar-occulted spectroscopy over the entire spectral range (1150-10,300 Å).

Table 4.1 and Table 5.1 provide a full list of gratings for spectroscopy and filters for imaging.

STIS is a versatile instrument that can be applied to a broad range of scientific programs. For instance, the combination of high spectral resolution covering a large simultaneous wavelength range and low per-pixel background improves the efficiency of programs such as quasi-stellar object (QSO) and interstellar absorption-line studies. STIS's wavelength coverage in a single exposure is 15 to 35 times that of GHRS for such applications. Studies of the dynamics of galactic nuclei and the kinematics of active galaxies and diffuse galactic nebulae benefit from the ability to obtain spatially resolved spectroscopy over a 50 arcsecond slit and from the high quantum efficiency in the optical provided by the CCD. The wide wavelength coverage of STIS facilitates line-ratio studies; for instance, the low-resolution first-order gratings span the range 1150-10,300 Å in just four exposures. Slitless spectroscopy provides emission-line images of astronomical objects, and coronographic imaging and spectroscopy can reveal the nature of extended gaseous regions surrounding bright continuum sources.