Increase of velocity.
Distance from the star. Angular approach to the star.
There were other readings, but those were the essential ones, those were the ones that counted.
And one thought rose in his brain, one thought that had been impressed upon it time after time:
To navigate a ship is not a matter of driving it toward a certain point, but in knowing where it will be at any time within the immediate future.
He made his calculations, the mathematics struggling upward into his consciousness.
He made the calculations and he made a graph and then reached out and pushed a control lever forward two notches and hoped that he was right.
"You are making it out?" Joshua asked.
Jon shook his head.
"We'll know—an hour from now we'll know."