Fast photometry mode possibilities for the Canarias Infrared Camera Experiment (CIRCE)

In this paper we analyze different solutions to implement a fast photometry mode in the Canarias InfraRed Camera Experiment (CIRCE), a visitor-class near-IR imager, spectrograph, and polarimeter for the 10.4 meter Gran Telescopio Canarias (GTC). The fast photometry mode will be one of the enhanced capabilities of CIRCE that will differentiate our instrument from similar instruments. The fast photometry capability, along with the polarimetric and spectroscopic capabilities of the instrument will provide a unique instrument for the study of rapidly-varying objects. We combine the different output modes of the HAWAII-2 2048x2048 detector, with very simple modifications in our already built Array Controller Subsystem (MCE-3), and with modifications in the firmware of the readout control electronics to provide the instrument with this powerful capability. We expect to increase the frame capture rate on the order of 5 to 14 times faster depending on the frame size and the final solutions chosen.