Multi-object spectroscopy via custom slitmasks is a key capability on three instruments at the W. M. Keck Observatory.
Before observers can acquire spectra they must complete a complex procedure to align each slit with its corresponding
science target. We developed the Slitmask Alignment Tool (SAT), to replace a complex, inefficient, and error-prone
slitmask alignment process that often resulted in lost sky time for novice and experienced observers alike.
The SAT accomplishes rapid initial mask alignment, prevents field misidentification, accurately predicts alignment box
image locations, corrects for flexure-induced image displacement, verifies the instrument and exposure configuration,
and accommodates both rectangular and trapezoidal alignment box shapes. The SAT is designed to lead observers
through the alignment process and coordinate image acquisition with instrument and telescope moves to improve
efficiencies. By simplifying the process to just a few mouse clicks, the SAT enables even novice observers to achieve
robust, efficient, and accurate alignment of slitmasks on all three Keck instruments supporting multislit spectroscopy,
saving substantial observing time.