GCN Circular 21931

T. Batsch, A.J. Castro-Tirado, H. Czyrkowski, A. �wiek, M. �wiok,
R. D�browski, M. Jel�nek, G. Kasprowicz, A.Majcher, K. Ma�ek,
L. Mankiewicz, K. Nawrocki, �. Obara, R. Opiela, L. W. Piotrowski,
M. Siudek, M. Soko�owski, R. Wawrzaszek, G. Wrochna, A. Zadro�ny,
M. Zaremba, A.F. �arnecki (Pi of the Sky Collaboration)

Pi of the Sky robotic wide field of view telescopes search for the
possible EM transients in the sky scans performed twice a night. Each
of the two observation sites (South telescope in Chile and the North
one in Spain) can cover up to about 20000 sq. deg. with range up to
about 12.5m. Dedicated algorithms search for brightness changes of
objects listed in GLADE to detect optical transients that might be
connected with those galaxies.

In the analysis related to G29048 we considered data collected by Pi
of the Sky North telescope located in Spain, near Huelva, between
August 17 and August 21, while the earlier data collected between
August 10 and August 16 were used as a reference. The observations
were performed in wide visible band, with IR-cut and UV-cut filters
only, to achieve deepest detection limit. For each scan field 10
images with 10s exposure were taken and stacked for the analysis. On
the night of 20170817 we surveyed area that overlaped partially with 
the initial bayesstar skymap for G298048. Unfortunatly, the dedicated 
scan procedure was interupted twice that night by the GCN alerts, 
resulting in the event coverage reduced to only about 29% probability, 
even after including other data collected that night. Coverage of 
about 51% was expected for uninterupted scan procedure, as 
obtained on the following nights. Data was searched for any type of 
transients connected with objects from GLADE catalogue. No 
significant transient candidate remained after all selection cuts.

We acknowledge hospitality and support of the INTA El Arenosillo 
Test Centre in Mazag�n near Huelva, Spain.


Fields covered with the sky scan procedure on 20170817
------------------------------------------------------

Pointing (RA[deg],Dec[deg]) gives the center of 20x20 deg^2 FOV.

Field name     Pointing
S0120_10_10   ( 10.8, -0.2)
S0000+50_35   ( 16.9, 57.1)
S0200+50_10   ( 17.7, 39.5)
S0120_10_35   ( 29.4, 18.1)
S0200+50_35   ( 47.0, 57.1)
S0000+90_35   ( 61.0, 77.4)
S1600+50_35   (227.7, 40.7)
S1600+10_10   (230.2,  0.1)
S0000+90_10   (244.6, 76.8)
S1600+10_35   (249.2, 18.0)
S1600+50_10   (257.5, 58.5)
S1840+10_10   (270.4,  0.0)
S2000+50_10   (287.8, 39.5)
S1840+10_35   (289.3, 18.0)
S2120+10_10   (310.6, -0.1)
S2000+50_35   (317.1, 56.9)
S2299+50_10   (317.6, 39.5)
S2120+10_35   (329.4, 18.1)
S2240+10_10   (330.5, -0.1)
S2299+50_35   (347.0, 57.3)
S0000+50_10   (348.0, 39.4)
S2240+10_35   (349.5, 18.2)

Fields covered with other sky observations on 20170817
------------------------------------------------------

GRB170817_35  ( 39.2, 79.9),
GRB170817_10  (250.2, 73.4),
GRB170818_35  (312.4, 10.7),

S0000-10_35   (  9.0, -1.9),
R0000+30_10   ( 11.3, 39.0),
S0200+50_10   ( 17.7, 39.4),
S0326+70_10   ( 33.0, 58.8),
S0326+70_10   ( 33.2, 58.8),
S0200+50_35   ( 47.0, 57.1),
S0326+70_35   ( 89.9, 75.9),
S1440+10_10   (210.2,  0.3),
S1440+10_35   (229.0, 18.2),
S1630+30_10   (236.9, 20.1),
S1630+30_35   (258.5, 38.0),
S2000-10_10   (289.8,-19.8),
S2000-10_35   (308.7, -1.7),
S2120-10_10   (309.8,-19.7),
S2200+50_10   (317.4, 39.4),
S2120-10_35   (328.9, -1.8),
S2240+10_10   (330.4, -0.2),
R0000+30_35   (349.6, 21.0),
S2200+50_35   (346.7, 57.2),
S2240+10_35   (349.3, 18.2),
S0000-10_10   (350.0,-19.8),

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