This was a snappy little puzzle, despite my time; I was distracted while doing it. I love the celebrity puzzler-puzzle professional mash up, especially in this case as I am a big fan of Dr. Tyson. I thought the theme answers were quite fun, if a little on the tried-and-true side. My favorite is probably 24A. Exxon Mobil? (GASGIANT). REDDWARF (Bashful?) is also nice both for the excellence of the clue and the double Ds in the answer. Perhaps Huygens prefers HEAVENLYBODY.
My only brief trouble spot was at 15A. Where I first put aTtA girl,possibly because I had seen it in another recent puzzle. But I was stopped from making ASBIG a mistake as I did on Saturday by realizing my error in time.
Despite 26 or so three-letter answers, we get only three abbreviations or initials (GMC, AAA, FTD), one Greek letter (PSI), and a Dolores, but that of course was never published. We also get OWE, OWL, and OWN, the only three-letter words starting with OW that are not plurals or onomatopoetics. That statement may or may not be true. Someone should check me on that.
There were quite a few nice clues in here. I liked 30D. Body part to lend or bend (EAR), 37D. Successful auctioneer's last word (SOLD), and, I can't resist after yesterday's puzzle: it's baaaaaack: (PSYCHO).
On a scales of OWN to TEN, ITSA RUBY!