TITLE:   GCN CIRCULAR
NUMBER:  28976
SUBJECT: GRB 201201A: DDOTI Observations 
DATE:    20/12/01 17:55:19 GMT
FROM:    Alan M Watson at UNAM  <alan@astro.unam.mx>

Nat Butler (ASU), Alan M. Watson (UNAM), Rosa L. Becerra (UNAM), Simone Dichiara
(GSFC/UMD), Alexander Kutyrev (GSFC/UMD), William H. Lee (UNAM), Océlotl Lopez
(UNAM), Diego Gonzalez (UNAM), Margarita Pereyra (UNAM), Srihari Ravi (ASU), and
Eleonora Troja (GSFC/UMD) report:

We observed the field of the Fermi/GBM likely long GRB 201201A (Fermi GBM Team,
GCN Circ. 28972) with the DDOTI wide-field imager at the Observatorio
Astronómico Nacional on Sierra San Pedro Martir (http://ddoti.astroscu.unam.mx)
from 2020-12-01 02:56 UTC to 03:39 UTC (from 4.4 to 47.2 minutes after the
trigger).

We observed a region covering 20.4 degrees in RA and 20.4 degrees in declination
(about 416 square degrees) centered on 19:23:21.60 +16:54:36.0 (J2000). We
obtained between 120 and 360 seconds of exposure in the w filter. We calibrated
our images against the APASS catalog. Our 10-sigma limiting magnitudes vary from
w = 16.4 to 18.2.

Compared to the USNO-B1, Pan-STARRS DR1, and APASS DR10 catalogs, we detect no
uncataloged sources to our 10-sigma limit.

We thank the staff of the Observatorio Astronomico Nacional in San Pedro Martir.