TITLE:   GCN CIRCULAR
NUMBER:  17704
SUBJECT: GRB 150413A: Bassano Bresciano Observatory optical observations
DATE:    15/04/14 15:49:55 GMT
FROM:    Ulisse Quadri at Bassano Bresciano Obs  <oabb@ulisse.bs.it>

U.Quadri, L.Strabla and R.Girelli report:

We imaged the field of GRB 150413A detected by SWIFT(trigger 637899)
with the robotic telescope of (IAU station 565) Bassano Bresciano 
Observatory, Italy (member of ISSP:Italian Supernovae Search Project)

The observations started 5.44 hour after the GRB trigger, at the end of twilight, 
with our schmidt telescope D=320/400 mm F/D=3.1.

Weather conditions were good.

We co-added 13 series of 10 exposures of 120 sec each.

Start T0+      End T0+      Vlim
---------------------------------
5.44 hour    10.26 hour     19.5

We clearly detect the optical counterpart
at the following coordinates:

12h 41m 41.78s +71d 50m 27s +-2 arcsc.

Magnitudes were estimated with the UCAC4 cat. 
and are not corrected for galactic dust extinction:

----------------------
      JD        CV mag  
----------------------
2457126.30650   17.92 
2457126.32100   17.94 
2457126.33532   18.10 
2457126.34963   17.83 
2457126.36395   17.99 
2457126.37827   18.02 
2457126.39258   18.21 
2457126.40691   18.10 
2457126.42122   18.21 
2457126.43482   18.28 
2457126.47849   18.54 
2457126.49282   18.78 
2457126.50714   19.20 

The image, and magnitude plot are available at:
http://www.osservatoriobassano.org/GRB.asp

The message may be cited.