Gemini multi-object spectrograph GMOS: integration and tests

The Gemini Multiobject Optical Spectrographs were designed to exploit the exceptional image quality anticipated form both the active and adaptive optics systems. High mechanical stability and repeatability and efficient reconfiguration and calibration were emphasized in the design, as well as the usual requirements of obtaining excellent image quality, high optical throughput and low optical distortion. In addition, an active flexure compensation system is used to assist in achieving a primary goal of attaining velocity accuracies of 2 km/s per spectrum in multiobject mode at the highest spectral resolution. Although the field is modest, small pixels are used to fully sample images as small as 0.2 inch and 28.3 million pixels will be recorded by the detector mosaic which consists of three 2048 * 4608 EEV CCDs. In this paper, results from extensive tests made during integration and testing of GMOS N components demonstrate that the design requirements are being met.