EIFIS (Extreme Integral FIeld Spectrograph) is a modular integral field
spectrograph, based on image slicers, and makes use of new, large format
detectors. The concept is thought to cover the largest possible field of view
while producing spectroscopy over the complete optical range (3 000 - 10 000
\r{A}) at a medium resolving power of about 2400. In the optimal concept, each
module covers a field of view of 38" x 38" with 0.3" spaxels, which is fed into
a double spectrograph with common collimator optics. The blue arm covers the
spectral range between 3000 and 5600 \r{A} and the red arm between 5400 and
10100 \r{A}, allowing for an overlap range. The spectra are imaged onto 9.2k x
9.2k detectors using a double pseudoslit. The proposed design for the 10.4m
Gran Telescopio Canarias uses a total of 6 such modules to cover a total of
2.43 square arcminutes. Here we will present the conceptual design of the
instrument and a feasibility study of the optical and mechanical design of the
spectrographs. We discuss the limitations and alternative designs and its
potential to produce leading edge science in the era of extremely large
telescopes and the James Webb Space Telescope.Comment: Submitted to the Proceedings of the SPIE, Astronomical Telescopes and
Instrumentatio