The ING has produced conceptual designs for a new refractive corrector for the prime focus of the 4.2m William Herschel Telescope that would allow coupling to a multi-object spectrograph.

Here we present two such designs that fulfil the demanding requirement that of PSF better than 0.5 arcsec (80% EE) over a two degree field of view and a wavelength range of 380nm-1000nm.

We discuss the science drivers and the design process, which has taken into account throughput, atmospheric dispersion correction and fibre coupling.

The designs are mature and form a basis for feasible manufacturable systems.