TITLE:   GCN CIRCULAR
NUMBER:  20605
SUBJECT: GRB 170205A: LCO FTN observations
DATE:    17/02/05 16:16:18 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

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

We observed Swift GRB 170205A (Troja et al. GCN 20603) on February 05, 
from 14:40 UT (2.0 hours since the GRB) with the 2-m LCO FTN in Hawaii 
with SDSS r and i filters. We detect the optical afterglow at the 
Swift-UVOT position with the following values:

Mid Time      Exposure       Filter       Magnitude (AB)
(hours)           (s)
-------------------------------------------------------
2.0             2x120         SDSS-R        20.3 +- 0.1
2.1             2x120         SDSS-I        20.0 +- 0.1
-------------------------------------------------------

as calibrated against nearby SDSS sources.