Even with the larger fibres, the throughput-stability of the design should allow sky-subtraction with an accuracy of better than 1 percent. The smaller fibres will capitalise on the good seeing conditions of the site. Ultimate limiting magnitude for absorption-line spectra is expected to be fainter than B21.5.
Autofib-2 and WYFFOS have been designed so that they can be operated independently of one another. A proposal already exists to use WYFFOS for integrated-field spectroscopy by means of a short reformatting fibre-feed from the Nasmyth focus. The modular construction of the Autofib feeds means that scope also exists for Autofib-2 to be used with a multi-object spectrograph other than WYFFOS. In combination or together, it is confidently expected that these two will form a cornerstone of the WHT's suite of instruments into the next millenium.