It was the scraggliest tree in memory when the Norway spruce from Oneonta, N.Y., arrived, maybe time or TV lights will enhance it by the time the switch is flipped (at about 9:45 p.m.) during The 88th Annual Christmas in Rockefeller Center (NBC, 8 p.m), where, for the first time in event history, the public will be banned out of coronavirus concerns.

Still, the “Today” crew of Savannah Guthrie, Hoda Hotb, Craig Melvin and Al Roker host. Performances will come from Dolly Parton, Gwen Stefani, Pentatonix, Meghan Trainor, Kelly Clarkson, Goo Goo Dolls, Earth, Wind & Fire, Brett Eldridge, Tori Kelly, Leslie Odom Jr., Dan + Shay, Jimmy Fallon, the cast of “Ain’t Too Proud” and the Radio City Rockettes, who will stick around for the special that follows, “Christmas Spectacular Starring the Radio City Rockettes at Home Holiday Special” (NBC, 10 p.m.).

The tree lighting is big enough annual entertainment to push to this afternoon a twice postponed NFL game. First scheduled for Thanksgiving, and then moved to Sunday and then Tuesday, the Baltimore vs. Pittsburgh (NBC, 3:40 p.m.) because of Covid among the Ravens. 

There’s already been one failed TV show about a fertility doctor who has inseminated scores of patients (Fox’s one-season “Almost Family” a year ago, remember?). Now comes a documentary about one such unscrupulous doctor who worked for decades in Las Vegas. “Baby God” (HBO, 9 p.m.) shows a doctor who might have thought he was helping infertile couples, but the first-time film by Hannah Olson takes an unexpected darker turn as they find a dozen unexpected half siblings. 

What if there was life on other planets?  The new “Alien Worlds” (Netflix, streaming) tries to imagine it with computer-generated animation and narration from Sophie Okonedo.