Fig. 2.

Top image: original GREGOR setup in side view from the vacuum exit window to F4. The location of the wavefront sensor (WFS) is indicated with an arrow. The wavelength splitting was made with a pentaprism (PP), and the instrument focal planes (F4) are shown for IR and VIS. Bottom image: new setup in top view. The VIS beam is reflected on the front side of the beamsplitter plate (BS). It is then split by a beamsplitter with a fraction of the light going into the AO. The IR beam passes the BS and is then reflected on M16. The WFS is located after all mirrors with power.
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