TITLE:   GCN CIRCULAR
NUMBER:  21754
SUBJECT: LIGO/Virgo G299232: observations of the optical Transient Discovered by Swift/UVOT
DATE:    17/08/29 18:57:50 GMT
FROM:    Alexei Pozanenko at IKI,Moscow  <grbgw.iki@gmail.com>

A. Pozanenko (IKI), A. Volnova (IKI), I. Reva (AFIF),  E. Mazaeva (IKI), 
P. Minaev (IKI),  M. Krugov (AFIF) report on behalf of IKI-GW follow-up 
collaboration:

We observed the field of the Optical Transient discovered by Swift/UVOT 
(Emery et al., GCN 21733)  with  Zeiss-1000 1-m telescope of Tien Shan 
Astronomical Observatory starting on 2017-08-28 (UT) 18:54:36. We 
obtained several images in R-filter.  The optical transient (Emery et 
al., GCN 21733) is not detected in a combined image.  Preliminary 
photometry of the afterglow is following.

Date       UT start   t-T0    Filter    Exp.   OT   Err.  UL
                   (Since LVC,mid, days) (s)         (3 sigma)

2017-08-28 18:54:36  3.24609  R         8*180  n/d  n/d  20.8

Photometry is based on nearby USNO-B1.0 stars (R2 magnitudes).
The nearest galaxy (SDSS J014008.25+343414.8) to the transient position 
in coordinates (J2000) 01 40 08.247 +34 34 14.43 +/- 0.25" is marginally 
detected. The galaxy is at a distance of 11.5 arcsec from the transient 
position. The galaxy photometry is R=21.45 +/- 0.45.