136 stars which were known to be the members of open cluster NGC 752 were observed at R band with ROTSE–IIId telescope located at the Turkish National Observatory ( TUG ) site .
The data had been evaluated together with BV and 2MASS photometric data .
A new practical method for separating dwarf and giant was described and applied .
Evaluating the colour magnitude–diagrams with Padova isochrones revealed metallicity similar to the Sun and an age of 1.41 Gyr for the open cluster NGC 752 .