OV Boo rare outburst
Observed: 15, 16, 29 Mar, 7, 20 Apr 2017
16, 17 Mar, 5 Jun 2017
Time-series at the outburst of March-April 2017 are reported.
OV Boo (SDSS J1507+52) is a cataclysmics system (dwarf nova, probably
WZ Sge type), usually around magnitude 19. In March 2017 it was reported
in outburst at magnitude 11. It has an unusually short orbital period
of 67 min. It is listed in VSX.
The observations were carried out with a 203 mm SC telescope, a V filter
and a Clear filter, and a ST7E SBIG camera (KAF401E CCD). For the light
curves, the exposure duration is 60s. For the photometry, the comparison
star is UCAC4 713-54077 (GSC 3868-01067) with an APASS V magnitude of
11.482 and an r' magnitude of 11.373. For the unfiltered observations,
the r' magnitude is used, as the CCD is mostly red sensitive. The resulting
Observed with a V filter. Green: OV Boo, Blue: a check star, UCAC4 713-54078, shifted by -1.2 mag.
The error bars are the 1-sigma statistical uncertaies (quadratic sum with the comparison).
Still with a V filter. About 0.3 mag dimmer than the previous night.
Still with a V filter and dimmer. The check star is shifted by +0.3 mag.
The object is so dim that I switch to a clear filter to have a better
signal. The check star is shifted by +1.3 mag. The eclipses are much deeper
as the object get dimmer; their positions are in agrement with the ephemeris
of Patterson et al (2008).
On April 20, 2017 I observed OV Boo at mag 16.2 unfiltered, exposure duration 200 s.
Patterson J. et al (2008) PASP 120 510.
Telescope and camera configuration.
Computer and software configuration.