MASTER: optical transients

ATel #10414; V. Shumkov, T. Pogrosheva, V. Lipunov (Lomonosov MSU), D. Buckley (SAAO), R. Rebolo, M. Serra-Ricart (IAC), E. Gorbovskoy, N. Tiurina, O. Gress, P. Balanutsa, A. Kuznetsov, V. Kornilov, V. Chazov, V. Vladimirov, I. Gorbunov, (Lomonosov MSU), A. Gabovich (BSPU)
on 22 May 2017; 21:35 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

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MASTER OT J065540.66-790035.2 discovery - new OT, possible dwarf nova outburst, Ampl>4.6m

MASTER-OAFA auto-detection system ( Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 30L ) discovered OT source at (RA, Dec) = 06h 55m 40.66s -79d 00m 35.2s on 2017-05-17.12230 UT.
The OT unfiltered magnitude is 17.4m (mlim=18.5m).
The OT is seen in 2 images on 17 May (02:39:58UT,02:56:07UT) and on 2 images on 18May( 2017-05-18 09:19:11, 09:27:19UT) .
We have reference image without OT on 2017-02-19.24904 UT with 19.7m unfiltered magnitude.
There is no known sources in VIZIER, it means 22m POSS limit in history and more then 4.6m of current outburst amplitude.
Spectral observations are required.
The discovery and reference images are available at:
http://master.sai.msu.ru/static/OT/065540.66-790035.2.png

MASTER OT J144921.27-340753.3 discovery - OT, ampl>4.8m

MASTER-OAFA auto-detection system discovered OT source at (RA, Dec) = 14h 49m 21.27s -34d 07m 53.3s on 2017-05-17.18531 UT.
The OT unfiltered magnitude is 17.2m (mlim=19.0m).
The OT is seen in 3 images on 17 May (04:26:51.367, 04:16:08.661, 04:05:31.488UT) and on 2 images on 18 May (2017-05-18 09:15:10.077, 09:11:24.615UT).
We have reference image without OT on 2017-04-20.24429 UT with 19.2m unfiltered magnitude limit .
There are 2 different stars in GSC2.3.2 in 4.6" and 4.8", too far from our position.
Spectral observations are required.
The discovery and reference images are available at:
http://master.sai.msu.ru/static/OT/144921.27-340753.3.png

MASTER OT J172322.47-010159.4 detection- Ampl>3.2m

MASTER-SAAO auto-detection system detected OT source at (RA, Dec) = 17h 23m 22.47s -01d 01m 59.4s on 2017-05-22.04959 UT.
The OT unfiltered magnitude is 18.8m (mlim=20.0).
The OT is seen in 3 images. There is no minor planet at this place.
There is MASTER-IAC image without OT with unfiltered mlim=19.7 on 2017-05-04 00:19:28UT.
Previous bright state was on 2016-03-12 01:36:15.833(3 images).
We have reference image on 2016-05-30.03441 UT with unfiltered mlim=19.8m.
There is USNO-B1 star with known B1=20.89, R2=19.69 (previous poss.short outbursts, like in CRTS database).
Spectral observations are required.
The discovery and reference images are available at:
http://master.sai.msu.ru/static/OT/172322.47-010159.4.png

MASTER Global Robotic Net