CHICAGO (AP) _ Consumers are gazing toward the heavens this Christmas season, but not to see the Star of Bethlehem. They're looking for Halley's comet, which has sparked a surge in telescope sales nationwide.

''Our telescope business is up better than 50 percent this year,'' said Thomas Spencer, manager of American Science Center on the city's Northwest Side.

The store sells the Edmund Astroscan 2001, the star of this season's telescope market,

''I get calls all day long from people asking about prices,'' Spencer said.

The Astroscan goes for $300, but dealers say models costing as much as $2,500 are selling like hot cakes.

In November, a national consumer magazine rated the Astroscan the best telescope under $500 for viewing Halley's comet. Since then, demand has soared and hundreds of stores nationwide are sold out until spring.

''The orders I have now I should be able to start filling in late January or February,'' said Dave McGonigle, vice president of Edmund Scientific Co., Astroscan's Barrington, N.J. manufacturer. ''But I'm still getting orders.''

The story is similar at other telescope manufacturers.

''We're cramming,'' said Kim Davey, a spokeswoman for Celestron International in Torrance, Calif. ''We've gone on triple shifts. We're working 24 hours a day to make telescopes.''

Michael Wagner, a spokesman for Meade Instruments Corp. in Costa Mesa, Calif., said, ''A good number of our products are sold out through the first quarter of next year.

''If a dealer doesn't have something in stock or on order now, he's not going to get it for a while.''

The backlog means many telescopes won't arrive in time for Christmas.

'I'll have to see the comet on its outbound leg because it will be late February or maybe March before my telescope gets here,'' said Robert Schmittinger of suburban Romeoville.

He's waiting for his Odyssey I to arrive from Coulter Optical Co. in San Bernardino, Calif. But with temperatures below zero, Schmittinger says he doesn't mind the delay.

''The telescope I ordered is basically for outdoor use,'' he said. ''You have to align it and get it all set up. Right now, by the time I did all that, I'd be ready to run back inside. The telescope is really a nice-weather telescope.''