Extensive effort has been made to define the requirement for a standby camera and spectrograph with capabilities similar to the current ALFOSC instrument. Considerations are the available space, requirements for imaging, spectroscopy, polarimetry, but also for calibration unit, an autoguider unit and an `adapter' unit, the latter taking in to account issues such as access to FIES, installation of its ADC and polarimetry units, requirements for NOTCam which will in principle be mounted permanently at Cassegrain (or just any instrument at the Cassegrain), but also the requirement to be able to mount a standby instrument like LuckyCam at a folded Cassegrain focus. Also, with the use of our FITS archive a more detailed analysis was made of the use of ALFOSC over a period of nearly two years to see what are its mainly used capabilities.
Currently the requirements are being reviewed. For the general design itself there is no specific requirement and any possible design such as having separate imaging and spectroscopic light path- ways, using a direct mode or a focal reducer, and/or blue and red arms with their respective CCDs are all possible options. However, it is clear that we need some basic constraints on the design before we can come to a more well defined set of requirements that can used to make a design study.
Thomas Augusteijn 2010-02-09