Аннотация:MASTER OT J182525.98+081046.9 discovery - dwarf nova outburst, ampl>4.7m
MASTER-OAFA auto-detection system ( Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 30L )
discovered OT source at (RA, Dec) = 18h 25m 25.98s +08d 10m 46.9s on 2018-04-13.24564 UT.
The OT unfiltered magnitude is 17.3m (mlim=18.4m).
The OT is seen in 4 images. There is no minor planet at this place.
We have reference images without OT on 2018-04-05 02:20:46UT with mlim=18.5 (MASTER-IAC); on 2018-03-16.36108 UT with unfiltered magnitude limit 18.6m (MASTER-OAFA).
There are previous outbursts in MASTER archive:
Date_UT , Unfiltered_magnitude, Observatory
2013-06-14 20:21:27.922 16.6 (MASTER-Kislovodsk)
2014-03-28 20:15:30.452 16.7 (MASTER-Tunka)
2014-04-04 01:13:09 no OT with mlim=17.5 (MASTER-Kislovodsk)
There is no USNO-B1 star (22m limit), but there were outbursts in 1990 (GSC 2.3.2 with only blue jmag=21.6 ) and in 2011 (Pan-STARR with red 21.58m)
Spectral observations are required.
The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/182525.98081046.9.png