Abstract
The multicolour CCD light curves of the eclipsing binary systems CRTS J213033.6+213159 and 1SWASP J212454.61+203030.8 are presented for the first time, the observations are analyzed using the latest version of the WilsonDevinney code. Both the systems are found to be W UMa contact binaries belonging two different subtypes. All the light curves show the inverse O'Connell effect. By using our 2 times of minimum light for both the systems and the 187 and 105 ToMs extract from the SWASP observations, respectively for CRTS J213033.6+213159 and for 1SWASP J212454.61+203030.8, the orbital periods are here revised. The spectral type K of the systems and their short orbital periods (<0.3 days), suggests that they are near the shortest period limit. The absolute dimensions are estimated and, from statistical diagrams, it is found that both components of the systems follow the general pattern of the relative subtype of W Ursae Majoris systems.
