2021RAA....21..174K

We present the first BVR photometry, period variation and photometric light curve analysis of two poorly studied eclipsing binaries, V1321 Cyg and CR Tau. Observations were carried out from November 2017 to January 2020 at the observatory of Uzhhorod National University. Period variations were studied using all available early published as well as our minima times. We used the newly developed ELISa code for the light curve analysis and determination of photometric parameters for both systems. We found that V1321 Cyg is a close detached eclipsing system with a low photometric mass ratio of q = 0.28 which suggests that the binary is a post-mass transfer system. No significant period changes in this system are detected. CR Tau is, on the other hand, a semi-detached system where the secondary component almost fills its Roche lobe. We detected a long-term period increase at a rate of 1.49 x 10-7 d yr-1, which supports mass transfer from the lower mass secondary component to the more massive primary.