PBS excelling with fine science specials

The Infinite Voyage: To the Edge of the Earth PBS, tomorrow, 8-9 p.m. Narrator: E.G. Marshall. Producer/writer: David Vassar. Produced by WQED, Pittsburgh, in association with the National Academy of Sciences. Discover: The World of Science PBS, tomorrow, 9-10 p.m. Narrator: Peter Graves. Producer: Chedd-Angier Production Company in association with Discover magazine.

Two of television's best science-magazine shows air back-to-back, providing a two-hour stretch of fascination and wonder.

The initial segment of ``The Infinite Voyage,'' which aired several months ago, focused on magical high technology being used in scientific research all over the world. The breathtaking special effects, skillfully photographed, almost overpowered the scientific workers being recorded. But it was still a dazzling show of technical virtuosity.

``To the Edge of the Earth,'' the second segment of this series, focuses a bit more on the people rather than the hardware. But it is just as dazzling a display. Starting out at New York's Explorers Club, the film hops to segments all over the world, visiting far-off places wherever scientists are exploring the unknown:

There's a visit to the nomadic tribes of Tibet, where researchers are finding a people at peace with the earth and within themselves.

There's a rare glimpse of creation 17 miles southeast of the island of Hawaii, where divers are observing a volcanic hot spot that is actually the summit of a new mountain forming 3,000 feet below sea level.

There's a voyage to the Gal'apagos (isn't every science show going there these days?), where evolution is put on hold in an underwater cave 90 feet below the surface.

There's an ascent to the canopy tops of the Costa Rican forests, where a rich layer of soil forms in the branches of trees 100 feet above the jungle floor and where trees sprout roots from their own branches.

There's a tour of polynyas, hot spots in the Canadian Arctic seas that provide food and water necessary to keep walruses - and some Eskimo tribes - alive.

This joyous series of scientific revelations is blessed with the dual satisfaction of entertainment and discovery. It is underwritten mostly by Digital Equipment Corporation, which is also airing it on some commercial and cable stations Jan. 11 (check local listings).

The January edition of ``Discover,'' a consistently fine science-magazine program produced in conjunction with the print magazine of the same name, is once again hosted by Peter Graves.

The program travels with a troop of Kenyan baboons to find out whether there is any relationship between the physical condition of these primates and their leadership position within the baboon society. One of the most interesting aspects of the story is how the photographer overcame the almost overwhelming difficulties of living and photographing in the wild.

Also investigated are new techniques in heart surgery for children and winemaking methods at a California vineyard.

PBS, with the regularly scheduled ``Nova'' and ``Nature,'' as well as ``The Infinite Voyage'' and ``Discover,'' is firmly establishing its position as the world's leading outlet for scientific and wildlife programming on TV.