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Centre for Advanced Instrumentation

Thousand Element Integral Field Unit (TEIFU)

Commissioning News

(June and Sept 1999 - 2 nights each). TEIFU was commissioned with ELECTRA on the William Herschel Telescope. During this short time the optical interface to both ELECTRA and WYFFOS was achieved and the performance quantified by flatfield and standard star observations. Early results are very encouraging with indication of good fibre-fibre response and overall system throughput. Finally, the entire Telescope+ELECTRA+TEIFU+WYFFOS system was tested by observing 3C237 with AO correction. Thanks to the the entire TEIFU and ELECTRA teams plus Don Pollaco and Frank Gribbin at the telescope.


TEIFU is a new system for two-dimensional (integral field) spectroscopy using adaptively-corrected images produced by the ELECTRA (and later, NAOMI) AO systems. It will also be able to operate in a stand-alone mode without an AO system.

The system will be mounted on an optical bench in the WHT GHRIL, fed by the Nasmyth focus, and will feed fibres into RGO's WYFFOS fibre spectrograph.


TEIFU parameters

Input from ELECTRA and/or NAOMI
Output to WYFFOS (f/1.2 camera)
Sampling (arcsec)



Field (arcsec) 2 x (7.0 x 3.9) 2 x (3.5 x 1.9)
Two separate fields to aid background subtraction
Object and sky fields movable within 80" AO field
IFU (only) throughput: ~60%; Filling factor: ~100%
Option for stand-alone operation without AO
Option for 0.5 arcsec sampling


Next stages

TEIFU has now successfully commissioned with the ELECTRA. The next stage is to modify the fore-optics for use with the NAOMI AO system which is partly based on ELECTRA and which should be completed in 2000.