TITLE:   GCN CIRCULAR
NUMBER:  18735
SUBJECT: LIGO/Virgo G211117: Pan-STARRS1 observations 2015-12-28
DATE:    15/12/28 16:05:20 GMT
FROM:    S. J. Smartt at Queens U Belfast  <s.smartt@qub.ac.uk>

K. C. Chambers, A. Schulz (IfA, University of Hawaii), D. Young, K. Smith, 
S. Smartt (Queen’s University Belfast),  M. Coughlin (Harvard), L. Denneau, 
H. Flewelling, A. Heinze, M. E. Huber, E. A. Magnier, N. Primak, A. Rest (STScI),  
A. Sherstyuk (IfA), B. Stalder (IfA), C. W. Stubbs (Harvard) J. Tonry, 
C. Waters (IfA), D. Wright, (QUB)

We report the observations of northern arc of the skymap defined by the 
BAYESTAR pipeline as reported GCN18728  with the Pan-STARRS1 telescope
(2.9 degree diameter FOV). 

We have mapped the arc from the southern point of RA=34.1174 DEC=10.129 
through to the northern tip at RA=86.394 DEC=53.6, corresponding 
to most of the 30% enclosed region in the northern arc of the BAYESTAR map. 

Observations were taken in the PS1 i-band (Tonry et al. 2012, ApJ 750, 99)
and at each pointing position a dithered sequence of 4 x 45 sec was taken, 
which will be combined as a single epoch stack. These dithered sequences
were repeated, with overlaps, to map the 30% region contiguously.  
A total of 371 individual 45 sec images were taken. 

Data taking began at  2015-12-28 05:07:49 and finished 2015-12-28 13:33:07
(UTC). 

The images are currently being differenced with respect to the Pan-STARRS
3Pi all sky i-band image (see Magnier et al. 2013, ApJS 205, 20 ; 
Huber et al. 2015,  ATel 7153) to detect transient objects. Further observations
of the region are planned as weather allows.