ATel #10577; O. Gress, V. Lipunov (Lomonosov MSU), D. Buckley (SAAO), E. Gorbovskoy, V. Kornilov, N. Tiurina, P. Balanutsa, A. Kuznetsov, V. Vladimirov, T. Pogrosheva, V. Chazov, V. Shumkov, D. Kuvshinov (Lomonosov Moscow State University, SAI)
on 17 Jul 2017; 15:07 UT
Credential Certification: Nataly Tyurina (

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

MASTER OT J154544.73-032127.6 discovery - new OT with ampl>4.5 (dwarf nova?)
MASTER-SAAO auto-detection system ( Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 30L ) discovered OT source at (RA, Dec) = 15h 45m 44.73s -03d 21m 27.6s on 2017-07-16.74758 UT.
The OT unfiltered magnitude is 17.5m (mlim=20.3).
The OT is seen in 7 images. There is no minor planet at this place. There is no any known sources in VIZIER database, it means 22m POSS limit in history and mre then 4.5 of current outburst amlitude's value
We have reference image on 2016-04-04.12737 UT with unfiltered mlim= 19.7m.
Spectral observations are required.
The discovery and reference images are available at:

List of Optical Transients discovered by MASTER

MASTER Global Robotic Net