y tracked it before either one of you went outside."

"How close?"

"Hm-m-m. Visually, a dozen kilometers, I'd guess. I could run the tape
if you--"

"Velocities almost the same?" asked Harcraft, who was now fiddling with
the viewscreen controls.

"Yeah. Shouldn't be too hard to find. How about lugging Bean Brain back
to his bunk. I'll run the tape, then you can plot it on the screen."

When Harcraft returned to the control cabin, Banner had already plotted
it on the screen.

"I'll say it's a big piece of rock! About four kilometers in diameter."

"Yeah, but nothing out of order."

"Uh-huh. Let me turn up the magnification a little and see if--" Banner
watched as Harcraft turned control buttons, skillfully increasing
magnification without losing the held of view. Suddenly, the object
exploded into iridescence. "What--"

"Watch," Harcraft said. He bumped the magnification as much as he
dared.

"The Ankorbadian fleet," said Banner between clenched teeth.

They spent the next hour scanning the ship's micro-library for anything
at all on Ankorbadian religious practices. There was nothing. Arnold
awoke in another hour and seemed remarkably free of hysteria.

"What do you know about our friends' religious holiday?" asked Banner.
"We checked the library without any luck."

Arnold scratched the side of his face. "Lemme think. Yeah, I remember.
They go home to celebrate spring, like you said."

"They all go home?"

"Uh-huh. They got to. Only time they can mate. Only place, too."

"How long they stay? I've heard it's about one of our months, but we
have to know exactly."

"That's all I know. Read it some place a long time ago. Can I go back
to sleep now?"

"Go back to sleep," said Banner.

They spent the next three hours maneuvering carefully around the
asteroid. They took six thousand feet of movies and stared at the
projections for another three hours. One thousand seven hundred and
thirty silvery needles flashed reflected starlight into astonished,
wild eyes.

"At least," whispered Banner, "there's nobody there."

"A lot of good that does us. They'll be back from their home planet in
a few weeks, just as soon as the breeding season is over. Why should
they leave anybody here? There's not a map in the galaxy that indicates
the position of this piece of rock. And we haven't any weapons."

"I don't suppose the computer--"

"You can't compute an orbit without at least one more reference point.
Beside