Presented are the results of a large and deep optical-near-infrared multi-epoch survey of the Praesepe open star cluster using data from the UKIDSS Galactic Clusters Survey .
Multiple colour magnitude diagrams were used to select potential members and proper motions were used to assign levels of membership probability .
From our sample , 145 objects were designated as high probability members ( p \geq 0.6 ) with most of these having been found by previous surveys although 14 new cluster members are also identified .
Our membership assignment is restricted to the bright sample of objects ( Z < 18 ) .
From the fainter sample , 39 candidates were found from an examination of multiple colour magnitude plots .
Of these , 2 have small but significant membership probabilities .
Finally , using theoretical models , cluster luminosity and mass functions were plotted with the later being fitted with a power law of \alpha = 1.11 \pm 0.37 for the mass range 0.6 to 0.125 M _ { \odot } and an assumed cluster age of 500 Myrs in the UKIDSS Z photometric band .
Likewise taking an assumed cluster age of 1 Gyr we find \alpha = 1.10 \pm 0.37 .
Similar values were also found for the J and K bands .
These results compare favourably with the result of ( ) ( \alpha = 1.4 \pm 0.2 ) but are significantly lower than that of the more recent study conducted by ( ) ( \alpha = 1.8 \pm 0.1 ) .