After yesterday, this was a cakewalk! The stacks were paper tigers, as the phrases fell ONEAFTERANOTHER (16A: Sequential). Frannie got THEGOBLETOFFIRE (17A: Harry Potter series part) first, and then things just kept rolling. A few tricky parts here and there, like the crossing of KENAI (26A: Alaska's ____ Fjords National Park) and LATAKIA (9D: Principal port of Syria). That is one that I think is totally unfair, but the rest had crosses that made them easier. SCACCHI (35D: Greta of "The Red Violin") and SNCC (35A: March on Washington grp.) was another guess, but really, it couldn't be many letters with that name.
I enjoyed the clues for SPOSE (53A: Quickly imagine?), and MELDING (7D: Putting one's cards on the table, in a way) (makes me think fondly back to playing canasta when I was much younger), and COFFER (11D: Strongbox) is a good word. NUEVA (30D: ____ York) and OSMOSES (39D: Seeps) (that's a verb?) seemed kind of cheap, and I'll have to defer final judgement to my astronomer friends, but EYELENS (44D: Telescope) also seems a little iffy. Isn't it an eyepiece?
Lots I didn't know - RESNIK, MIASARA, UAR, SCACCHI, LATAKIA, HAME… but it all went down, so I guess it's all right.
Favorite part? 58D: Bad computer? (HAL)