Photometric studies of two W UMa type variables in the field of distant
  open cluster NGC6866
  We present photometric analysis of the two W UMa type binaries identified in
the field of distant open star cluster NGC6866. Although these systems, namely
ID487 and ID494, were reported in the Joshi et al. (2012), but a detailed study
of these stars has not been carried out earlier. The orbital periods of these
stars are found to be 0.415110+/-0.000001 day and 0.366709+/-0.000004 day,
respectively. Based on the photometric and infrared colours, we find their
respective spectral types as K0 and K3. The photometric light variations of
both the stars show O'Connell effect which could be explained by employing a
dark spot on the secondary components. The V and I bands light curves are
analyzed using the Wilson-Devinney (WD) code and relations given by Gazeas
(2009) which yield radii and mass of the primary and secondary components of
the star ID487 as R1 = 1.24+/-0.01 Rsun, R2 = 1.11+/-0.02 Rsun, and M1 =
1.24+/-0.02 Msun, M2 = 0.96+/-0.05 Msun, and for the star ID494 as R1 =
1.22+/-0.02 Rsun, R2 = 0.81+/-0.01 Rsun, and M1 = 1.20+/-0.06 Msun, M2 =
0.47+/-0.01 Msun.
