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Table 9.

Geometric parameters for the telescope pupil, the intermediate pupil, and the pupil stop masks in the SPHERE visual coronagraph.

din (mm) dout (mm) wspid (mm) geom. Tgeom
Telescope 1148 8200 41 VLT
coro. pupil 0.896 5.97 0.037 VLT
pupil stops
Clear 6.60 100%
stop3 1.80 5.40 0.036 diag. 72.9%
stopB1 1.20 5.41 0.110 VLT 75.5%
stopB2 1.81 4.79 0.107 VLT 53.5%
stopB3 1.81 5.40 0.106 VLT 70.9%
STOP1_2 1.2a 5.4a 0.084 diag.+b 74.8%
STOPB1_2 1.2a 5.4a 0.18 VLT+b 72.6%
SAMa 7 holes

Notes. The columns indicate the pupil or stop name, the diameter din and dout of the inner stop and the outer edge, the width wspid and the geometry of the spider arms, and the geometric transmission Tgeom. Roman fonts give design values or values measured for the mechanical components, while italic fonts are values measured from pupil images;

(a)

The sparse aperture mask is described in Cheetham et al. (2016) and was not tested by us.

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