TITLE: GCN CIRCULAR NUMBER: 23520 SUBJECT: MASTER: OTs detection during Fermi alert trigger 565936249 early observations DATE: 18/12/08 10:10:39 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs A.Chasovnikov, V. Lipunov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D.Vlasenko, I.Gorbunov, A.Krylov Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University R. Podesta, Carlos Lopez and F. Podesta Observatorio Astronomico Felix Aguilar (OAFA) Hugo Levato Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory K. Ivanov, O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev, V. Poleshchuk Irkutsk State University V. Yurkov, A. Gabovich, Yu. Sergienko Blagoveschensk Educational State University, Blagoveschensk R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias D. Buckley, S. Potter, A. Kniazev, M. Kotze South African Astronomical Observatory MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the possible long GRB181208.19 17 sec after notice time and 123 sec after trigger time at 2018-12-08 04:32:47 UT. On our first (20s exposure) set we found 617 optical transient within FERMI error-box (ra=103.917 dec=-66.59 r=3.05) brighter than 18.2. MASTER OT J063515.49-624002.9 - No known CV. MASTER-OAFA auto-detection system ( Lipunov et al., "MASTER Global Robotic Net",Advances in Astronomy, 2010, 30L ) discovered OT source at (RA, Dec) = 06h 35m 15.49s -62d 40m 02.9s on 2018-12-08.19993 UT. The OT unfiltered magnitude is 17.2m (mlim=19.0m). The OT is seen in 2 images. There is no minor planet at this place. There is 21 mag star in USNO-B1.0 catalog with 0.5 arcsec offset. We have 22 November 2018 image without object with 18.4 mag limit. We have reference image without OT on 2018-02-19.09796 UT with magnitude limit in 'BLANK' filter 20.2m. Cheking of the robots OT candidtates is continuated. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/063515.49-624002.9.png Spectral observations are required. MASTER OT J231531.76-304848.3 - 13 mag Known Dwarf Nova in Flare! MASTER-IAC auto-detection system discovered OT source at (RA, Dec) = 23h 15m 31.76s -30d 48m 48.3s on 2018-12-07.79828 UT. The OT unfiltered magnitude is 13.3m (limit 18.9m). The OT is seen in 16 images. There is no minor planet at this place. We have reference image without OT on 2018-10-01.03255 UT with unfiltered magnitude limit 19.5m. Spectral observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/231531.76-304848.3.png The covered map is available at http://master.sai.msu.ru/static/png/GRB181208.19/FERMI//224854545.png.1.png The covered map is available at http://master.sai.msu.ru/static/png/GRB181208.19/FERMI//224854545.png.3.png The 5-sigma upper limit has been about 18.3mag The galactic latitude b = -24 deg., longitude l = 277 deg. The observations made on zenit distance = 39 deg.The moon ( 1 % bright part) below the horizon (The altitude of the Moon is -37 deg. ). The sun altitude is -35.5 deg. The object can be observed till sunrise at 2018-12-08 09:24:03 This message can be cited.