How 'translucent' are translucent molecular clouds ? by Dr. Frank Bensch (CfA)   Translucent molecular clouds are characterized by low visual extinction, typical ly on the order of a few magnitudes.They are not gravitationally bound and show no signposts of star formation. The chemistry is expected to be governed by the interstellar FUV field, and as transition objects, with only a fraction of their carbon being converted to CO, they possibly represent early stages of molecular cloud formation. I will present recent observations and results for MCLD 123.5+24.9 in the Polari s Flare, a translucent molecular cloud close to the North Celestial Pole. The sp atially extended emissionof the [CI] 3P_1 to 3P_0 fine-structure transition of n eutral carbonwas observed with the Subillimeter Wave Astronomy Satellite. It is the first [CI] map made for a translucent cloud and for the first time allows a study the global distributionof [CI] for this class of objects. The SWAS data is complemented by ground based observations of CO and high density tracers. The [ CI] emission is relatively weak compared to CO, and its contribution to the clou d cooling is only small. These data will be compared to current PDR (photo-domin ated region) models, which fail to reproduce observations in a few key instances .