Up to December 2, 2002
This is the lightcurve of the symbiotic star V1261 Orionis since I first observed it back in December 2000.
Irregular variations between 6.67 and 6.95 have been recorded and two fading episodes when the star got to 7.0 are well-documented as well.
These fadings are ~645 days apart, which corresponds perfectly with the period of the eclipsing binary proposed by Jorissen et al. HOWEVER, they are not in phase with the predicted epoch. Something must be wrong since the eclipses are pretty identifiable...
This is the first one I recorded, around JD 2451935.
This is the most recent eclipse. The light curve is more accurate due to the developing of a better observing technique during the last couple of years.
This eclipse is centered around JD 2452580.
These are the only two occasions when the star got as dim as 7.0.
The above phase diagram is made based on a 645 days- period and shows the fit of the first (blue dots) and the recent (red dots) eclipses. Surprisingly this period make the eclipses appear at phase -0.01 of the orbital cycle according to Jorissen and Mayor (1992)
Lightcurve of V1261 Orionis since 1989 through 2002.
Then you can find more details in two year-light curves.
Obviously, the presence of the intrinsic variations due to the interaction of the white dwarf and the giant's wind make every study a difficult one.
Maybe the two more recent eclipses are more apparent because they took place in more quiet or brighter states of the system. Anyway, more observations are needed.
References:
Adelman, S. 1997, Baltic Astronomy, 6, 391
Jorissen A., Mayor M. 1992, A&A, 260, 115
Jorissen A., Mayor M., Manfroid, J., Sterken, C. 1992, IBVS No 3730
Perryman, M.A.C., et al., 1997, The Hipparcos and Tycho Catalogues, ESA SP-1200
Sterken et al, Long-term photometry of Variables II-IV (1993-1995)