MASTER: optical transients

ATel #9252; P. Balanutsa, O. Gress, V. Lipunov (Lomonosov MSU), D. Buckley (SAAO), R. Rebolo Lopez, M. Serra-Ricart (IAC), E. Gorbovskoy, E. Popova, D. Kuvshinov, A. Kuznetsov, V. Kornilov, D. Vlasenko, O. Gress, S. Shurpakov (Lomonosov Moscow State University, SAI), S. Potter, A. Kniazev (The South African Astronomical Observatory)
on 18 Jul 2016; 01:00 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

Tweet

MASTER OT J194507.47-200720.5 discovery - possible dwarf nova outburst, ampl>5.7m

MASTER-IAC auto-detection system ( Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 349171 ) discovered OT source at (RA, Dec) = 19h 45m 07.47s -20d 07m 20.5s on 2016-07-11.00663 UT.
The OT unfiltered magnitude is 16.3m (limit 18.8m).
The OT is seen in 3 images. There is no minor planet at this place.
We have reference image without OT on 2016-06-12.06234 UT with unfiltered magnitude limit 19.8m.
There is no optical sources inside 4" in VIZIER database, it means the 22m POSS upper limit for it and current amplitude more then 5.7m
Spectral observations are required.
The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/194507.47-200720.5.png

OT MASTER OT J221522.20-481807.2 discovery - dwarf nova outburst, ampl>4.5m

MASTER-SAAO auto-detection system discovered OT source at (RA, Dec) = 22h 15m 22.20s -48d 18m 07.2s on 2016-07-11.97927 UT.
The OT unfiltered (0.2B2+0.8R2 calibrated by tens of thousands USNO-B1 stars) magnitude is 17.9m (the limit is 20.9m).
The OT is seen in 8 images. There is no minor planet at this place.
We have reference image without OT on 2015-09-05.83031 UT with unfiltered magnitude limit 21.0m.
There is GSC2.3.2 star in 1.3" with known blue jmag=22.34(1977 year previous outburst), it means the amplitude of current outburst is more then 4.5 Spectral observations are required.
The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/221522.20-481807.2.png

MASTER OT J175159.18+704949.3 discovery, ampl>4m

MASTER-IAC auto-detection system discovered OT source at (RA, Dec) = 17h 51m 59.18s +70d 49m 49.3s on 2016-07-16.09128 UT.
The OT unfiltered magnitude is 16.1m (limit 18.6m).
The OT is seen in 2 images. There is no minor planet at this place.
We have reference image without OT on 2015-07-17.15769 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/175159.18704949.3.png

MASTER Global Robotic Net