1) “Nova,” 9 p.m., PBS. A solar eclipse (shown here) requires lots of coincidences, we’re told. That starts with the fact that the sun is 400 times the moon’s size and 400 times as far away. The April 8 eclipse will cut a swath from Dallas to Montreal, with 4-plus minutes of blackout. The start of this interesting hour has warnings – even with special glasses, don’t look through a telescope or camera – and details.
2) “Walker” season-opener, 8 p.m., CW. When CW dumped most of its dramas, this was one of the few survivors. Now it’s back with a big, busy hour. Alongside Walker’s birthday party, crises build. His daughter was emotionally shattered by an attack … his ex-colleague Cassie leads a fierce shoot-out … and a serial killer is loose.
3) “Sight Unseen” 9 p.m., CW, rerunning at 9 p.m. Friday. Canadian networks supply CW with crime-solving duos. “The Spencer Sisters” and “Wild Cards” were fun; now comes a serious twist: A police detective is going blind; hesitant to tell her colleague, she uses a body-cam linked to someone who talks into her earpiece. Parts of this feel contrived, but the characters and cases are solid.
4) “Loot,” Apple TV+. The second season finally begins — 20 months after the first one ended – and crackles with wit. Maya Rudolph plays a divorcee, deciding how to dole out billions. Some of the laughs comes from her lush life; others come from the great supporting cast, especially Ron Fuches as Howard, her tech guy.
5) Comedies. It’s the second straight rerun-Wednesday for ABC. Jackie takes her mother to Chicago on “Conners” (8 p.m.) … there’s a newspaper awards event on “Not Dead Yet” (8:30) … and “Abbott Elementary” (9)) gets a librarian. Each is a tad below these show’s high standards. You could go to Fox for “The Masked Singer” and a 9 p.m. rerun of the terrific “Animal Control” season-opener.