TITLE:   GCN CIRCULAR
NUMBER:  20072
SUBJECT: GRB161017A: optical observations with 1-m LCOGT McDonald
DATE:    16/10/18 11:18:07 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi (U. Ferrara), S. Kobayashi, I.A. Steele (LJMU), C.G. Mundell 
(U. Bath), A. Gomboc (U. Nova Gorica) on behalf of a large collaboration 
report:

The 1-m LCOGT McDonald telescope began observing Swift GRB161017A (Troja 
et al., GCN 20064) in the SDSS r filter on October 18, 10:03 UT (~0.67 
days since the GRB). We detect the optical afterglow (Yurkov et al. GCN 
20063; Troja et al. GCN 20064; de Ugarte-Postigo et al. GCN 20069; 
Fujiwara et al GCN 20070; Melandri et al. GCN 20071) with r=18.95 +- 
0.10 mag at 0.68 days mid epoch, as calibrated against nearby SDSS stars.