MASTER-OAFA: CV outburst

ATel #11535; D. Savinov, V. Shumkov (Ozersk), V. Lipunov (Lomonosov MSU), R. Podesta (OAFA), H. Levato (ICATE), V. Kornilov, E. Gorbovskoy, N. Tiurina, P. Balanutsa, A. Kuznetsov, V. Chazov, D. Vlasenko, V. Vladimirov, O. Gress, T. Pogrosheva, D. Zimnukhov, I. Gorbunov, A. Krylov (Lomonosov Moscow State University, SAI), C. Lopez, F. Podesta (Observatorio Astronomico Felix Aguilar San Juan University), C. Saffe (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio), V. Senik (KSS), A. Gabovich(BSPU), D. Kuvshinov
on 14 Apr 2018; 17:44 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

Subjects: Optical, Request for Observations, Cataclysmic Variable, Transient, Variables

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

List of Optical Transients discovered by MASTER

MASTER Global Robotic Net