Over the past several months, the Sci-Fi Channel has been making tentative strides in original programming. First, in June, it was new episodes of “Sliders,” formerly on Fox. Then came the original series “Welcome to Paradox” in August.

Now the cable channel has said goodbye to “Paradox” and is moving “Sliders” to Friday nights, to team with three new programs in its Sci Fi Prime (without the hyphen) lineup.

Opening the lineup at 7 p.m. is “Poltergeist: The Legacy,” offering new episodes of the series which had been syndicated for its first three seasons.

“The Legacy” is about an ancient society that fights malevolent supernatural forces. The group is led by anthropologist and theologist Dr. Derek Rayne (played by Derek de Lint) and includes psychiatrist Rachel Corrigan (Helen Shaver), researcher Alex Moreau (Robbi Chong) and ex-Navy SEAL Nick Boyle (Martin Cummins).

Even though a program on the paranormal seems out of place in this lineup, “The Legacy” comes off like a darker “Profiler,” as a team of experts tries to explain that which can’t always be explained by psychological conditions. It’s certainly not for everybody, as good battling such clear-cut evil as murderous spirits and black magic isn’t most people’s idea of harmless escapism.

The second show of the evening at 8 p.m. is “Farscape,” created by the Muppet masters, The Jim Henson Company, and the prestigious, much-honored Hallmark Entertainment.

“Farscape” is the latest in the enduring (and endearing) genre of science fiction, in which a group of life forms with nothing in common gets thrown together and must depend on one another for survival (actually, this goes back to Hitchcock’s “Lifeboat.”)

John Crichton, played by Ben Browder (“Party of Five”) is a second-generation astronaut, a scientist who has lived in the shadow of his test-pilot father. While flying a shuttle in space to test out his theory, he ends up being sucked into a wormhole and lands a thousand galaxies away, in the midst of an alien battlefield.

Through a series of accidents and misunderstandings, Crichton finds himself uneasy allies with a brutish warrior, a blue, centuries-old priestess, a 26-inch-tall sovereign of a fishlike race, and a disgraced soldier forced to join these rebels. Set aboard a living ship with a built-in pilot, the motley crew seeks to stay one jump ahead of the Peacekeeper force pursuing them.

Filmed Down Under with a largely Australian cast, the “Farscape” creators, led by executive producer Rockne S. Bannon (“Alien Nation,” “Seaquest DSV”), have done a laudable job developing an enjoyable series centered on Crichton, a stranger in a strange land. Most credibly, the exotic aliens don’t distract from the story itself. It will be simple for viewers to jump on and enjoy the ride.

After “Sliders,” perhaps the most ambitious of the new shows, “First Wave,” premieres at 10 p.m. “First Wave” is a dense series with plenty of back story, which isn’t surprising, since it has been created by Chris Brancato, who has written for “The X-Files” and “The Outer Limits.”

The title refers to a prediction made by Nostradamus in 1564, in which he tells of an apocalyptic invasion coming in three waves: the first wave — an elite infiltrative and saboteur force, the second wave — invasion from above, and the third wave — Armageddon. He also foretells of the coming of Earth’s savior, who will lead the fight against the aliens — the “twice-blessed” man (this is going to be a little harder to pick up than “Farscape”).

Cade Foster is that savior. A thief during his misspent youth, he’s reformed and now sells security equipment. He’s happily married to wife Hannah. And his world is about to be turned upside down.

It turns out that Foster, played by Canadian actor Sebastian Spence, is one of 117 subjects in an alien experiment on human psychology. He has been having strange hallucinations, and his bank accounts have been mysteriously wiped out. With the help of another experiment subject, a businessman now locked in a mental institution, he soon uncovers a vast conspiracy of alien infiltration of Earth, but not before he has been framed for his wife’s murder. So now Foster is on the run from the police, the aliens, and a mysterious government agent.

“First Wave” enjoys that “Fugitive”-like quality now on display in “The Pretender” and “Strange World,” but both those shows feature earthbound shadowy quasi-governmental organizations. In its smartly paced opener, “First Wave” sets many things in motion and generates many questions. It is hoped it won’t take six years to answer some of them.

The more established “Sliders” is the best thing that the Sci Fi Prime lineup has to offer. The space opera “Farscape” is tops among the new shows, followed by “First Wave” for the conspiracy buffs and “Poltergeist: The Legacy” for fans of the supernatural. In any event, Sci Fi Channel is to be praised for its renewed commitment to quality original programming.