A STIS image of stars in the elliptical galaxy NGC 205 together with stars in the foreground from our own Milky Way. Image: STIS parallel program. Image reduction: Phil Plait.

The Space Telescope Imaging Spectrograph (STIS) is a versatile "combi-instrument" taking advantage of modern technologies. It combines a camera with a spectrograph, and covers a wide range of wavelengths from the near-infrared region into the ultraviolet. A spectrograph spreads out the light gathered by a telescope so that it can be analyzed to determine such properties of celestial objects as chemical composition and abundances, temperature, radial velocity, rotational velocity, and magnetic fields. Its spectrograph can be switched between two different modes of usage:

1. So-called "long slit spectroscopy" where spectra of many different points across an object are obtained simultaneously

2. So-called "echelle spectroscopy" where the spectrum of one object is spread over the detector giving better wavelength resolution in a single exposure

STIS also has a so-called coronograph which can block light from bright objects, and in this way enables investigations of nearby fainter objects.

The Space Telescope Imaging Spectrograph (STIS).	A STIS spectrum of the galaxy NGC 4151 revealing that gas is flowing out of a black hole in its centre.

	WFPC2 - Wide Field Planetary Camera 2
	NICMOS - Near Infrared Camera and Multi-Object Spectrograph