We present a preliminary analysis of time-resolved X-shooter spectroscopy of HW Vir, a post-common envelope binary system, comprising of hot subdwarf B primary and a cool M dwarf secondary. Aiming at detecting and analysing the irradiated light of the superheated hemisphere of the M dwarf, we demonstrate that HW Vir is a bona fide double lined system allowing us to directly derive the masses of both stars and consequently backtrack the controversial evolution of subdwarf B stars and test the mass-radius relation of low mass stars.

Eclipsing binaries (EBs) are a key which opens the door to a chamber of knowledge. Thus the research of EBs in open clusters (OCs) is very promising. However, only several lists of eclipsing binaries known in OCs have been published, the last one almost three decades ago. We introduce a new catalogue of EBs in the field of open clusters. In addition we establish a new program for skilled amateur astronomers who are able to produce a significant amount of photometric data of sufficient accuracy. Photometry as well as spectroscopy of selected EBs in OCs will be used to determine stellar parameters of components in binaries and cluster parameters.

After a detailed investigation of new observations obtained by small telescopes, we found a group of near and shallow contact binaries with decreasing period including BS Vul, MR Com, EP Cep, ES Cep and V369 Cep. BS Vul and V369 Cep are primary-filling near-contact binaries, while MR Com, EP Cep and ES Cep are shallow contact binaries. With their decrease in period, BS Vul and V369 Cep will evolve to the shallow-contact systems with higher mass ratios, just like ES Cep. The period decease of shallow contact binaries could be caused by the combined effect of the thermal relaxation oscillation (TRO) and variable angular momentum loss (AML). This produces contact binaries in oscillating circles that evolve towards the lower mass ratio direction. That means systems resemble ES Cep will evolve to those systems with lower mass ratio, such as MR Com and EP Cep.