[vsnet-grb-info 20134] GRB 171209A: Lulin 1m telescope observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22230
SUBJECT: GRB 171209A: Lulin 1m telescope observations
DATE:    17/12/10 17:59:29 GMT
FROM:    Albert Kong at NTHU  <akhkong at gmail.com>

GRB 171209A: Lulin 1m telescope observations

A.K.H. Kong (NTHU, Taiwan) reports

We observed the field of GRB 171209A (LaPorte et al. GCN 22213) with
the 1m telescope at the Lulin Observatory in Taiwan. The observations
were done with the SDSS r and i filters and the first observation were
started at 2017-12-09 20:20:16 UT (5.6 hours post burst). We detect
the optical afterglow identified by the UVOT and LCO (Guidorzi et al.
GCN 22214). We obtained the following magnitudes:

Start time     Exposure     Filter     Magnitude (AB)
20:20:16       300s         SDSS-r     19.47+/-0.11
20:25:50       300s         SDSS-i     18.97+/-0.09

The magnitudes were calibrated with nearby Pan-STARRS objects.