[vsnet-grb-info 19878] GRB 171001A: Nanshan-0.36m optical afterglow detections

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  21957
SUBJECT: GRB 171001A: Nanshan-0.36m optical afterglow detections
DATE:    17/10/02 12:21:09 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu at nao.cas.cn>

H.J. Tan (CCU), H.X. Feng, D. Xu, Z.P. Zhu (NAOC), Y.D. Hu (IAA-CSIC), 
Y. Qin (Geneva Obs.), X. Gao (Urumqi No.1 Senior High School) report:

We observed the field of GRB 171001A (Lien et al., GCN 21946) using the 
0.36m robotic telescope located at Nanshan, Xinjiang, China. 
Observations started at 18:37:21 UT on 2017-10-01, i.e, 701 sec after 
the BAT trigger, and all imaged were taken without filter.

The optical afterglow was detected at the XRT position (Evans et al., 
GCN 21952) with coordinates

R.A. (J2000) = 01:28:18.67
Dec. (J2000) = -11:53:39.0

with an uncertainty of ~0.5 arcsec.

Our photometry was summarized as follows:
========================================
Tmid(s)+T0   Exptime(s)       Mag(R)           MagErr

741                40*2            >17.60

902                60*2              17.93              0.13

1102              60*3              18.00              0.11

1328              90*2              18.55              0.11

1522              90*2              18.60              0.20

3327              90*8             >18.75
========================================
Note: (1) Photometry is calibrated with stars in the USNO B1 catalogue 
in the R-filter, although images were taken without filter. (2) MagErr 
is the only statistical error of the measurement. (3) The magnitudes are 
not corrected for the Galactic extinction.