The study of orbital parameters of multiple Ap stars may lead to new suggestions about the origin and magnetic properties of the components. 53 Cam is one of the best studied binaries among Ap stars. However, the nature of its secondary star remains unclear despite the wealth of spectroscopic observations. The system was first directly resolved by speckle interferometry method in 1980 at the 4 m KPNO telescope McAlister et al. (1983). The authors supposed that the magnitude difference between the components could be close to zero. From that time, 16 speckle measurements of the system were made, including 7 observations collected with the SAO 6 m telescope. In addition to relative positions of the components, speckle observations from the 6 m telescope provide high accuracy magnitude difference estimates.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html