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,
222 m arcsec.