TITLE:   GCN CIRCULAR
NUMBER:  17695
SUBJECT: GRB 150413A: Khureltogot optical observations
DATE:    15/04/14 02:02:12 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

S. Schmalz (AIP),   N. Tungalag (Research Center of Astronomy and Geophysics 
MAS),   A. Pozanenko (IKI),  E. Mazaeva (IKI), A. Volnova (IKI), I. Molotov 
(KIAM), report on behalf of larger GRB follow-up collaboration:

We observed the field of the GRB 150413A (Markwardt  et al., GCN 17688; 
Serino et al., GCN 17691) with ORI-40 telescope of Khureltogot observatory 
starting on Apr., 13 (UT) 14:08:52 and finishing on Apr. 13 (UT) 20:08:39. 
The afterglow   (Ivanov et al., GCN 17689, Tyurina et al., GCN 17690, 
Schmalz  et al., GCN 17692, Xu et al., GCN 17693, Klose et al., GCN 17694) 
is detected up to the end of our observations. Preliminary light curve 
obtained for single unfiltered images and calibrated against nearby 
USNO-B1.0 stars (R2 mags) can be found in 
http://grb.rssi.ru/GRB150413A/GRB150413A_ORI40_lc.jpg

In particular, our photometry on Apr., 13 (UT) 19:21:35 R=17.2+/-0.1 is 
compatible with photometry at (UT) 19:23 reported by Klose et al. (GCN 
17694).