The GMACS Mask Simulator (GMACS-MS) is a slit mask design and visualization program for GMACS. GMACS-MS is a plug-in for ESO Skycat, a catalog and .fits viewer. It is a modified version of OSMOS Mask Simulator  (OMS). Skycat is known to run on Linux and MacOS X. During development, GMS was tested using a virtual machine running Fedora 14 and is currently the only confirmed working platform. A screenshot displaying several of GMS’s features is shown below.
Shown above, the cyan rectangle is the CCD footprint of the GMACS detector, and the white circle is the boundary of the instrument focal plane. After an image is loaded, a custom or online catalog can be initialized and create the various ellipses shown on the field which mark object locations. Using the ‘Auto-Slit’ function, shown in the drop-down menu above, creates the slits as shown above. When saved, the program outputs three files which can be used for manufacturing, visualization, and cross-checking of the mask template with expectations. As the underlying framework of GMS remains the same as OMS and the earlier LUCI Mask Simulator (LMS), a detailed overview of features can be found in the LMS User Manual .