Front optics design of TIFR-ARIES Multi-Object Optical to Near Infrared Spectrometer (TA-MOONS)

Abstract

TA-MOONS is a multi-object Optical to Near Infrared (NIR) spectrometer with the primary science cases to conduct a spectroscopic survey of Young Stellar Objects (YSO’s) at visible as well as at NIR wavebands simultaneously at a spectroscopic resolution of R~2700. The wavelength coverage of this instrument is from 0.36-2.50 microns. The instrument is jointly developed by TIFR and ARIES, designed for 3.6 meter Devasthal Optical Telescope (DOT)1 as a second generation main port instrument. The instrument is capable of observing 8-sources simultaneously within the sky field of view (FoV) of 12 arcmin diameter with its front optics deployable slit (DS) technique. These are mirror based 8-pickup arms located around the telescope focal plane. The DS is a novel concept consisting of tiny mirror-based arms having translation and rotational motion to pick up the source within each arm’s patrol field. This manuscript presents the optical design of front optics and probe viewer/calibration optics. Conceptual idea of the two-arm spectrometer also presented.