WHT f/11 Nasmyth
WHT f/2.8 corrected
WHT f/11 Cassegrain focus
Focal plane position: Nominal position 150 mm below A&G mounting face and 800 mm behind instrument rotator. Range of movement possible
1500 mm about this position.
Field size: 15 arcmin unvignetted, 19 arcmin with 50% vignetting.
Image quality: At nominal focus on a flat focal plane,
0.5 arcsec over a 10 arcmin field and
1 arcsec over a 20 arcmin field.
Image scale: At nominal focus, 4.51 arcsec mm
Tue Aug 15 16:42:46 BST 1995