TITLE:   GCN CIRCULAR
NUMBER:  21932
SUBJECT: GRB 170728B: Kottamia R-band observation
DATE:    17/09/27 06:13:52 GMT
FROM:    Yasser Hendy at NRIAG  <y_hendy_yasser@yahoo.com>

TITLE:   GCN CIRCULAR
NUMBER:  
SUBJECT: GRB 170728B: Kottamia R-band observation
DATE:    17/09/27 6:09 GMT
FROM:    Yasser Hendy at NRIAG  <y_hendy_yasser@yahoo.com>
 
G. B. Ali, Y.H.M. Hendy, A. Takey, N. Essam, and A. Essam 
National Research institute of Astronomy and Geophysics, NRIAG, Egypt

report on behalf of the Kottamia collaboration:

We observed the field of the short GRB 170728B: trigger=765130 
(Cenko S. B. et al., GCN Circ. 21371) with the 1.88m telescope 
of the KAO (Kottamia Astronomical Observatory), Egypt. 
The observation was performed in the Rc-band at the Newtonian
camera (F4.8) and started at 2017-07-29 T18:11:19 UT 
(~ 19.13 hours (0.8 day) after the burst). 

We obtained four images in the Rc-band each one with 600s exposure
time.  We clearly detected the optical afterglow (D'Avanzo et al., GCN Circ.
21372/21373; Heintz et al., GCN Circ. 21374; Guidorzi et al., GCN Circ. 21375; 
Izzo et al., GCN Circ. 21381; Kitaoka et al., GCN Circ. 21387; Watson et al., 
GCN Circ. 21389; Dintinjana et al., GCN Circ. 21394; Volnova et al., GCN Circ. 21419). 

We estimate a magnitude Rc 20.625 +/- 0.133, calibrated against nearby 
USNO-B1.0 stars:

  USNO-B1.0    R2 
1601-0108297  13.35
1600-0109901  13.61
1600-0109913  14.08
1601-0108263  14.58
1601-0108285  14.59
1601-0108292  14.71
1601-0108254  15.04
1600-0109911  15.42
1600-0109861  15.52
1601-0108199  15.66
1600-0109905  15.92
1600-0109885  15.97

-Yasser Hendy, on behalf of tthe Kottamia collaboration
 GRB followup team.



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Dr. Yasser Hassan Mohamed  Mohamed  Hendy 
National Research Institute of Astronomy & Geophysics (NRIAG), 
Astronomy Department, 11421 Helwan, Cairo, Egypt. 
Phone: +202 25560645      Fax: +202 25548020      Mobile: +20 1007580213    +20 1145385285     
Email: y_hendy_yasser@yahoo.com  yasserhendy@nriag.sci.eg   yasserhendy@mail.ru 
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