GRB 201221D: 3.6m DOT optical observations

We carried out the follow-up observations of GRB 201221D (Page et al., GCN 29112) with Aries Devasthal Faint Object Spectrograph and Camera (ADFOSC) mounted on the 3.6m Devasthal Optical Telescope (DOT) at Devasthal observatory of Aryabhatta Research Institute of observational sciencES (ARIES), India. The observations were started on 2020-12-22 at 23:10:00 UT. We observed a series of 4 images with the exposure time of 900 seconds each in r-band. At the position reported by Malesani et al., (GCN 29117), we detect an uncatalogued source in r-band with a magnitude of 23.46 +- 0.09 (AB mag), calibrated with the nearby PanSTARRS field. However, we remark that this is an extended source and may contain significant host galaxy contribution. For further verification, host galaxy subtraction is highly encouraged. The magnitude is not corrected for the Galactic extinction in the direction of the burst. This circular may be cited.