As of Tuesday, Twilight: New Moon's astonishing box office performance in the US was showing little sign of slowing down. It took a further $10m on Monday and $11m on Tuesday in the US alone, to add to its $142m opening weekend, and with its total at $164m and growing, there's an increasing feeling that the film's second weekend could play ahead of predictions.

The competition out this weekend certainly plays in the film's favour. The gruesome-looking Robin Williams-John Travolta comedy Old Dogs will sweep up some degree of the family audience, while Ninja Assassin is very much aimed at an older crowd. That leaves Twilight's main target demographic pretty much uncatered for, almost as if everyone else was getting out of the way of New Moon's arrival.

Conventional wisdom usually suggests that a film, at least a very hyped blockbuster, drops 60% in its second weekend. That alone would point to a figure in the region of $60m for New Moon, which is where we suspect it'll end up. But could the film do more than that? Most pundits suspect not, with some even suggesting that it may drop to somewhere closer to $50m. But we suspect the limited competition will give it a little more than that.

Either way, Twilight: New Moon will definitely be crossing the $200m mark at the US box office this weekend, and the numbers will give us a firm indication of just what legs the film has. We can see it playing right through to January and continuing to bring in sizeable audiences over Christmas, too. Could Transformers 2's position as the number one movie be under threat, though? That we'll have an idea of by Monday....