End to End Optical Modelling: From instrument design to pipelines

Several wide-field multi-object spectrographs and integral field spectrographs are proposed for the upcoming ELTs and National large optical telescope project in India. These will provide optical and near-infrared spectroscopy of large samples of astronomical objects and also aid in very specific science goals like spectroscopy of directly-imaged exoplanets. The size and complexity of these instruments scale with the telescope aperture size creating unique problems for optical design. Mitigating some of these design challenges involves the development of new simulation tools that can interface with different standard optical and mechanical design software to simulate realistic observations and instrument behavior. Similarly, end-to-end simulations and modelling offer unique ways to extract the best data out of even the current instruments. I will discuss such efforts in the context of instrument design of MOIS: Multi-Object Infrared Spectrograph being designed by the IR group at TIFR. I will also discuss how such modelling efforts aid in developing reduction pipelines and early performance analysis in the case of TMT-IRIS and Keck-SCALES lenslet-based spectrographs.