The Taurus and LDSS focal reducers, and to a lesser extent the two prime focus correctors, contain a large number of glass elements which limit the efficiency outside the wavelength range for which the optics, and particularly the anti-reflection coatings are optimised. For this reason imaging in U and I with Taurus and especially LDSS is not recommended. The Cassegrain auxiliary port of the WHT, and the JKT direct CCD camera, provide the most efficient options for U band imaging.
Taurus is only recommended for applications involving narrow-band interference filters, which it is desirable to place in the collimated beam. The passband of narrow-band interference filters is broadened and shifted by the fast converging beam of INT and WHT prime focus.