Fiber Linked Experimental (FLEX) 

First light: 1988. HEXAFLEX saw first light on1 May 1989.

Last commissioning: 

Participating organisations: Instituto de Astrofísica de Canarias.

Description: FLEX is a grating spectrograph specially suited to fiber work. It offers many optical configurations. One of them is a reflective configuration, in which the camera has a Cassegrain-Mastukov design working at f/2.2 (f = 197 mm). The secondary mirror of the camera has a diameter of 50 mm, giving a central obstruction of 33%. In this case, a set of three different parabolic mirrors, all of them with a diameter of 100 mm and working aproximately at f/4, f/6 and f/8, can be used as collimators. The other configuration is refractive and uses a large field lenses /f/6.3, f = 508 mm) as collimator and the TAURUS II camera (f/2, f = 128 mm).

FLEX can be placed on one of the Nasmyth platforms of the WHT. 

HEXAFLEX consists of two fiber bundles mounted simultaneously on the spectrograph, which allow one to change the spatial and spectral resolution without any modification in the spectrograph's configuration. At the focal plane, the 61 fibers of each bundle are arranged in a hexagonal lattice, which permits regular and symmetrical mapping.

More information: http://www.iac.es/cat/hexaflex.html

More photos of this instrument: http://www.ing.iac.es/PR/archive/wht/instruments.html