Observed: 2, 8, 18, 25 June, 5, 16, 17 July, 5 August 2005
1 July 2005
Updated: 6, 22 July, 17 August 2005
Time-series for this anti-dwarf nova are presented.
V442 Oph is a cataclysmic star, that is binary with an accreting white dwarf.
In the Ritter + 2003 catalog of cataclysmic binaries (VizieR V/113A) it is classified
as a Nova Like, of the VY Scl category (anti-dwarf nova whose brightness
may fall by several magnitudes over extended periods). It is also of the SW Sex category
(high inclination, peculiar spectroscopy). It is also listed as having an orbital period
of 0.12433 day and another period of 0.12090 day.
V442 Oph is a CBA
target for July 2005.
The observations were carried out with a 203 mm f/6.3 SC telescope,
a SBIG ST7E camera (KAF401E CCD) and a Clear filter. 611 images were obtained.
Each exposure is 1 mn long.
The comparison star is GSC 6235-02678 at RA=17h32mn11.93s DEC=-16°14'51.8"
with an assumed unfiltered magnitude of 13.17. The check star is an
anonymous star at RA=17h06mn06.92s DEC=-16°13'17.7" with a measured magnitude
of 15.02 (standard deviation 0.11).
A sample image is here.
Red: V442 Oph, Green: the check star, shifted by +1.5 mag. The error bar are +/- 1 sigma
the statistical uncertainties. The air mass was < 2.5.
The air mass was high at the end of the session (see below) but the
The Moon at 34° and hazy sky.
Does the pulse-like feature disappears when the object becomes weak?
V442 Oph was also observed on June 8, 18, 25 under poor sky conditions,
on July 17 (2 images) and on August 5 (1 image). The variation of the average magnitudes:
Telescope and camera configuration.
Software and computer configuration.