Optical spectroscopy of 93 galaxies , 60 projected in the direction of Abell 1367 , 21 onto the Coma cluster and 12 on Virgo , is reported .
The targets were selected either because they were detected in previous H \alpha , UV or r ^ { \prime } surveys .
The present observations bring to 100 % the redshift completeness of H \alpha selected galaxies in the Coma region and to 75 % in Abell 1367 .
All observed galaxies except one show H \alpha emission and belong to the clusters .
This confirms previous determinations of the H \alpha luminosity function of the two clusters that were based on the assumption that all H \alpha detected galaxies were cluster members .
Using the newly obtained data we re-determine the UV luminosity function of Coma and we compute for the first time the UV luminosity function of A1367 .
Their faint end slopes remain uncertain ( -2.00 < \alpha < -1.35 ) due to insufficient knowledge of the background counts .
If 90 % of the UV selected galaxies without redshift will be found in the background ( as our survey indicates ) , the slope of UV luminosity function will be \alpha \sim -1.35 , in agreement with the UV luminosity function of the field ( Sullivan et al .
2000 ) and with the H \alpha luminosity functions of the two clusters ( Iglesias-Paramo et al .
2002 ) .
We discover a point like H \alpha source in the Virgo cluster , associated with the giant galaxy VCC873 , possibly an extragalactic HII region similar to the one recently observed in Virgo by Gerhard et al .
( 2002 ) .