Yep, this is pretty meaningless. Captrek seems convinced that the Klingons were shooting at clouds, despite evidence from the theatrical release that they knew there was an object at the center. In that original release, the Klingons reported home, saying: We don't know what happened previously to provoke them, but Klingons don't need much provocation to unleash their dogs of war, and if V'Ger pulled a stunt with the Klingons at all similar to what it did with Comm Station Epsilon IX, then they're perfectly justified sending whatever they have in to counter-attack. This movie was made when the film makers still realized that a weapon with the specifications of a photon torpedo would do a lot more damage than knock the paint off a starship's hull. In the original series and The Motion Picture, a photon torpedo detonated with a force greater than nukes. Later in the film, a single photon torpedo smashes an asteroid to rubble as a demonstration. It certainly doesn't matter if V'Ger is a diminutive spec compared to the cloud. It was a power field and a simple analysis of the lines of force would point back to the center. V'Ger conveniently gave them handy cross-hairs for targetting in a "bummer of a birthmark" move that, realistically, was probably unavoidable considering it's capabilities. They didn't just fire three photon torpedoes and then run away, either (although it's easy to make that mistake from the way the scene is edited). They continued to attack, so the salvo we saw was just the opening round of a battle that the Klingons presumably intended to prosecute with torpedo barrages until they got close enough to cut into the target with beam weapons, or it surrendered or broke. What they didn't count on was watching their super-nukes vanish without effect. And the Captain's response was to order evasive maneuvering, not a retreat. So let's summarize: The Klingons weren't shooting at the cloud, they were shooting at the object they knew was at the center. They weren't firing beam weapons, they used -- as Timo notes -- strategic weapons capable of causing massive damage even if they missed. These were only the first shots of battle that the Klingons intended to continue as they closed range. They made the mistake of being overly aggressive against an opponent who vastly outclassed them, but they certainly weren't trying to destroy a target that was 82 (or just 2) astronomical units in diameter.