TITLE: GCN CIRCULAR NUMBER: 22418 SUBJECT: Swift trigger 810300: MASTER-OAFA robotic report DATE: 18/02/16 09:46:38 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, O.Ershova, N.Tyurina, V.Kornilov, D.Zimnukhov, A.Krylov, I.Gorbunov, P.Balanutsa, A.Kuznetsov, V.Chazov, D. Kuvshinov (Lomonosov Moscow State University, SAI), V.Yurkov, A.Gabovich, Yu.Sergienko (Blagoveschensk Educational State University, Blagoveschensk), R.Podesta, C.Lopez, F. Podesta (Observatorio Astronomico Felix Aguilar (OAFA),National University of San Juan, Argentina), H. Levato, C. Saffe (Instituto de Ciencias Astronomicas,de la Tierra y del Espacio (ICATE), San Juan, Argentina), D.Buckley, S. Potter (South African Astronomical Observatory), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), O.Gres, N.M.Budnev, Yu.Ishmuhametova (Irkutsk State University), A. Tlatov, V.Senik, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory) MASTER-OAFA robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Argentina was pointed to the Swift trigger 810300 (Barthelmy et al. GCN #22416) 23 sec after notice time and 1742 sec after trigger time (18/02/16 05:37:23.51UT) at 2018-02-16 06:06:26 UT with unfiltered mlim=19.1 (5-sigma) on single images, 19.9m on sum(1800s). There is marginally seen optical source, possibly known 2MASS source in 1.3" (with known J-K=1) from SWIFT XRT (D'Avanzo et al. GCN #22417) center RA (J2000.0) = 16 58 12.58 DEC (J2000.0) = -42 41 55.7 inside 3.83 arcsec error-box (radius, 90% containment). The message may be cited. ==================================================================== The observations were made on zenit distance = 66 degrees, galaxy latitude b = -1 degree. The Moon altitude is -44 degree . The Sun altitude is -42.2 degree. The object can be observed till sunrise at 2018-02-16 10:15:34