ISIS

The Intermediate dispersion Spectrograph and Imaging System (ISIS) is mounted at the Cassegrain focus of the 4.2m William Herschel Telescope. ISIS is a high-efficiency, double-armed, medium-resolution (8-120 Å/mm) spectrograph, capable of long-slit work up to ~4' slit length. Use of dichroic slides permits simultaneous observing in both the blue and red arms, which are optimised for their respective wavelength ranges. Linear and circular spectropolarimetry and imaging polarimetry are also available, as well as a drift-scan mode for high-time resolution monitoring programmes. Some historical aspects of ISIS can be found at the public information web pages.

The CCD currently in use on the blue arm of ISIS is a thinned, blue-sensitive EEV12, an array of 4096×2048 (13.5 micron) pixels. This is the default device for the ISIS blue arm. The default chip for ISIS red is RED+. It is a red-sensitive array of 4096×2048 (15.0 micron) pixels with almost no fringing.

You can either apply for observing time with ISIS through one of the ING time-allocating committees or through the ING Service Programme.

News:

September 2008: Two new electron-multiplying ‘Low-Light-Level’ L3CCDs are available for fast or faint-object spectroscopy on both ISIS arms.