MBCAA Observatory

IQ Eri: a cataclysmic in outburst

Observed: 27, 28 Dec 2008

Michel Bonnardeau
28 Dec 2008
Updated 29, 31 Dec 2008


Time series for this cataclysmic variable in outburst are presented.


IQ Eri (=1RXS J025538.2-224655) was detected in outburst by Monard (2008). This is the first outburst since the discovery of this cataclysmic system in 2002.


The observations were carried out with a 203mm f/6.3 SC telescope, a Clear filter and a SBIG ST7E camera (KAF401E CCD). 361 images were obtained, each with an exposure duration of 60s.

For the differential photometry, the comparison star is GSC 6437-00137 with an assumed unfiltered magnitude of 11.8. The check star is GSC 6437-00013 with a measured average magnitude of 13.063, an average 1-sigma statistical uncertainty of 0.027 and a standard deviation of 0.040.

The resulting light curves:

Session 27 Dec 2008

Red: IQ Eri, blue: the check star shifted by +0.3mag. The error bars are +/- the 1-sigma statistical uncertainties. The average 1-sigma statistical uncertainty of the check star is 0.027, the standard deviation 0.037.

It looks like there is a pulsation with a period around 18mn, but this is not confirmed the night that follows.

IQ Eri is low over my horizon (it is at DEC=-22 and I am at 45N). However the sky was fairly good:

The photometry zero point as a function of the airmass. The blue dot line is a linear fit, the green line is 0.1mag below. There are a few measurements that are not too good (below the green line) but I did not filter out any data.

Red: the air mass, blue: the photometry zero point shifted by -20 mag.

Session 28 Dec 2008

The average 1-sigma statistical uncertainty of the K is 0.027, the SD is 0.042.

3 images were discarded because of the extra losses (much below the green line).


Monard L.A.G. (2008) IAU CBET 1633.

Technical notes

Telescope and camera configuration.

Computer and software configuration.

Data processing.

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These measurements are in the AAVSO International Database, observer BZU.
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