TANSPEC: TIFR-ARIES Near-infrared Spectrometer

We present the design and performance of TANSPEC, a medium-resolution $0.55-2.5~\mu$m cryogenic spectrometer imager, now in operation at 3.6-m Devasthal Optical Telescope (DOT), Nainital, India. The TANSPEC provides three modes which include, photometry with broad- narrow-band filters, spectroscopy short slits 20$^{\prime \prime}$ length different widths (from 0.5$^{\prime to 4.0$^{\prime \prime}$) cross-dispersed mode resolving power R $\sim$2750, long 60$^{\prime prism $\sim$100-350. TANSPEC's imager field view \prime} \times 60^{\prime plate scale 0.245$^{\prime \prime}$/pixel on DOT. was successfully commissioned during April-May 2019 subsequent characterization astronomical observations are presented here. has been made available worldwide community for science from October 2020.