TKOF WITHOUT TKOF ALTERNATE.

Narrative

THE FLT WAS CONDUCTED AS A SCHEDULED AIRLINE UNDER FAR PART 135. AFTER OBTAINING THE LCL ATIS; I RELATED THE INFO TO THE CAPT THAT THE FIELD WAS ABOVE TKOF MINIMUMS BUT BASED ON VISUAL OBSERVATIONS; IT APPEARED THE FIELD CONDITIONS WOULD CONTINUE TO DETERIORATE BEFORE OUR SCHEDULED DEP. THE FLT WAS BOARDED AND A RTE CLRNC OBTAINED. UPON TAXI; THE GND CTLR STATED THAT THE RVV HAD DROPPED TO 1/4 MI AND THE RVR WAS RPTED AT 1000 FT. I QUERIED THE CAPT CONCERNING OUR LEGALITY ABOUT LEAVING WITHOUT A SUITABLE TKOF ALTERNATE. HE ASSURED ME THAT NONE WAS REQUIRED SINCE THE RVV WAS AT OUR REQUIRED MINIMUM OF 1/4 MI. I; HOWEVER; NOTED TO THE CAPT THAT I THOUGHT THE RVR WAS CTLING AND WAS BELOW THE 1200 FT MINIMUM OUR OP SPECS REQUIRED. THE CAPT DISAGREED AND STATED THAT THE RVV SATISFIED THE REQUIREMENT. BEING NEW TO THIS COMPANY AND BEING VERY JUNIOR TO THIS CAPT; I FELT THAT I WAS IN ERROR AND SIDED WITH THE CAPT'S DECISION. THE FLT DEPARTED WITHOUT INCIDENT AND WAS UNEVENTFUL. AFTER THE CONCLUSION OF THE SCHEDULED SHIFT; I RESEARCHED THE SIT MORE CAREFULLY AND FOUND THAT WE HAD NOT MET THE REQUIRED TKOF CRITERIA. THE SENIORITY OF THE CAPT MADE IT DIFFICULT FOR ME TO FULLY EXPRESS MY CONCERNS AND USE THE PROPER RESOURCES TO FIND THE CORRECT ANSWER. WHILE I DID RECEIVE TRAINING IN COCKPIT RESOURCE MGMNT DURING MY NEW HIRE PERIOD; IT IS EVIDENT THAT CREW COMS STILL NEED TO BE IMPROVED. HAD I ASKED THE CAPT FOR 3 MINS AT THE END OF THE RWY TO CONSULT THE PROPER REF; IT WOULD HAVE CERTAINLY SAVED US BOTH A LOT OF EMBARRASSMENT.