PVD CTLR EXPERIENCED OPERROR AT 2100 FT AS B737 ON VISUAL APCH EXTENDED BEYOND CTRLINE AND CONFLICTED WITH OPPOSITE DIRECTION BASE LEG TFC.

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I WAS WORKING AN ARR RUSH. THE INCIDENT OCCURRED ABOUT MIDWAY THROUGH THE RUSH. I WAS FOCUSED ON VECTORING TO AS TIGHT AN INTERVAL AS POSSIBLE TO AVOID A 'DAISY CHAIN' EFFECT SLOWING THINGS DOWN. OUR AIRSPACE ENDS APPROX 15 MI FROM THE RWY THRESHOLD SO IT IS NECESSARY TO AVOID LETTING THE PATTERN GET STRUNG OUT INTO THE NEXT FACILITY'S AIRSPACE. I TURNED THE B737 ONTO A BASE; POINTED OUT TFC FOR THE ACFT TO FOLLOW; AND DSNDED THE ACFT TO THE MVA IN PREPARATION FOR A VISUAL APCH. THE B737 PLT CALLED THE TFC TO FOLLOW IN SIGHT; SO I ISSUED A 10 DEG TURN TOWARD THE ARPT TO TIGHTEN THE SEQUENCE A LITTLE MORE; INSTRUCTED THE ACFT TO FOLLOW HIS TFC AND CLRED THE B737 FOR A VISUAL APCH. I DID NOT REALIZE THAT THE SETTING SUN WAS BECOMING A FACTOR; BUT THE B737 PLT EXTENDED HIS BASE ACROSS THE FINAL BECAUSE HE WASN'T QUITE SURE WHERE THE RWY WAS BECAUSE THE SUN WAS IN THEIR EYES. I HAD TURNED THE F2TH'S BASE FROM THE OPPOSITE SIDE TOO SOON TO LEAVE ADEQUATE ROOM BEHIND THE B737 EVEN IF THE B737 HAD TURNED TO THE FINAL NORMALLY. THE B737'S FORAY ACROSS THE FINAL EXACERBATED THE PROB. I ISSUED AN IMMEDIATE TURN AWAY FROM THE B737 TO THE F2TH AND INSTRUCTED THE B737 TO TURN TOWARD THE ARPT AND MAKE A VISUAL APCH. IN RETROSPECT; I BELIEVE I LET MY CONCERN FOR RUNNING A TIGHT SEQUENCE CLOUD MY JUDGEMENT ABOUT WHEN TO TURN THE F2TH'S BASE.