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Previous Page: Startup and basic concepts
Next Page: Creating the input catalogue
The multiaperture mask in the focal plane of LDSS-2 must have an accurately positioned slit for each target object, and also 3 or more larger holes to allow accurate alignment of the mask and the target images. LEXT has facilities which make it relatively simple to design a mask either from direct images of the target field or from previously measured image positions. Once the design of a mask has been completed, LEXT writes out a file which describes the position and size of the slits and fiducial holes. Observatory staff can then use the file to manufacture the mask with a computer controlled milling machine.
Note that it is essential to save the catalogue files and have them accessible to the LEXT package at the telescope so that the fields can be acquired.