"Are you sure of it?" demanded Stutsman.

"Of course. I don't make blunders."

"It's the only type G star in that direction," suggested Chambers, helpfully.

"Not that, either," declared Craven. "In fact, there are several type G stars. I examined them all and I know I'm right."

"How do you know?" challenged Stutsman.

"Spectroscopic examination. That collector field of ours gathers energy just like a burning glass. You've seen a burning glass, haven't you?"

He stared at Stutsman, directing the question at him.

Stutsman shuffled awkwardly, unhappily.

"Well," Craven went on, "I used that for a telescope. Gathered the light from the suns and analyzed it. Of course it didn't act like a real telescope, produce an image or anything like that, but it was ideal for spectroscopic work."

They waited for him to explain. Finally, he continued: