Introduction

Pupil plane is set by AT M2. The specifications for the AT foci are shown in Table 20.1. The distances of the AT mirrors along the optical axis are given in Table 20.1.

Focus	f-ratio	focal length	image scale	Field of view
		($\mbox{m}$)	( $\mu \mbox{m arcsec}^{-1}$)	($\mbox{arcmin}$)	($\mbox{mm}$)
Nasmyth	25.0	45.0	218	8	104.6
Coudé	36.2	65.2	316	2	37.8

Mirror	Distance from	Physical distance	Reimaged distance
Mirror	last mirror	from M1 along axis	from f/1 image plane
	($\mbox{mm}$)	($\mbox{mm}$)	($\mbox{mm}$)
M1	0.0	0.0	Near pupil plane
M2	2493.4	2493.4	Pupil plane
M3	1793.4	4286.8	Near pupil plane
M4	1450.0	5736.8	$8$
M5	1630.0	7366.8	Near pupil plane
M6	950.0	8316.8	Pupil plane image
M7	4400.0	12716.8	Near pupil plane
M8	1344.6	14061.4	Near pupil plane
M91	2470.2	16531.6	Near pupil plane