European Southern Observatory
New Technology Telescope

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Echelle Mask Setup

When Echelle spectroscopy is performed with red gratings #10 or #14 (but not #9 !!), this mask is usually used to block some extra diffuse light. It is a mechanical piece (#302) which is stored in cup board #1. In the instrument it is located between the two 45 deg mirrors (LOMR and UPMR units).

Press EMMI emergency stop button at the center of EMMI cover.
Remove the large red cover from the front of EMMI.
If the mask has to be removed, unscrew the 2 bolts and then rotate the mask by 180 deg around an axis perpendicular to the EMMI structure. Take it out.
If the mask has to be installed, unscrew the two bolts, enter first the `head' of the mask in the slot and then rotate it by 180 deg around an axis perpendicular to the EMMI structure. At the end, the number `302' written on the mechanical piece should appear up right.
Screw in the two bolts on their EMMI screws whether you removed or installed the mask.
Put back EMMI cover.
Release the emergency stop button.

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