I sensed it was about time for a Silkie, and I was not wrong. A slight variation on the pinwheel, with triple-9's in the down pattern, but only a pair of 11's across - rare to see cheater squares from our constructor. Some proper names flummoxed me, but I did finish, in my personal allotted time; we have -
17A. Dawn star : TONY ORLANDO - Oddly, I already had 1-down, and so I thought this was going to be "PLANET VENUS", which is the 'dawn star'; presently it's the 'evening star' at magnitude -4.5. here's a page for any amateur astronomers out there. As for Tony, he's here.
55A. City south of Mombasa : DAR Es SALAAM - Tanzania, Africa - map, to the right
13A. Fright to the max : SHEER TERROR - this is my kind of sheer
51A. Emergency exit : ESCAPE HATCH - Nailed it, with no crossings, either - what's your favorite "escape hatch" movie moment ???
1. Play matchmaker for : FIX UP
6. Support spec : B-CUP - ya know, I was going to put in _ CUP, but I thought, no, we're not that DF here, are we???
10. Shorten : LOP
16. Maine in D.C., e.g. : AVE - map, at the bottom
18. With 36-Across, many a thirtysomething, briefly : GEN and 36A. See 18-Across : XER
19. Mil. address : APO - A little edification for you
20. Emollient : BALM
21. Concealed : COVERT
23. Netflix transactions : RENTALS
25. National Museum of Indonesia setting : JAKARTA - more geography - was a movie in the late 80's, too, that I liked.
26. Hagen of Broadway : UTA
27. Bowler's accessory : ROSIN BAG - When I play goalie at deck hockey, I use my bowling shoes for better side-to-side "slip"; a rosin bag is for better grip - baseball, too, right C.C.? (!)
28. Astrologer Dixon : JEANE - I knew this, but not how to spell the name.
31. Al __ : DENTE
32. Skeletal opening? : EXO
33. Optic layer : UVEA
34. All CIA directors, to date : MALES
35. It's opposite the face : PEEN - Ah, hammer - sad to say, I did not think of this right away - but then again, I use claw hammers all the time....
37. Exposes : BARES
38. Braces : GIRDS
39. 480-grain ounce, e.g. : TROY UNIT - The Wiki
41. Spot : PIP
42. Loser : ALSO-RAN
43. Writing pair : PEN-PALS - I once wrote to my cousin in England for a whole year during my teens; it was great getting the letter, but we just didn't have much in common.
47. Easy outs : POP-UPS - More baseball for our eager fans awaiting opening day; personally, I am keyed up for the presently NHL-leading Rangers to run deep into June.
48. "Lulu" composer : BERG
49. __ cit.: in the place sited : LOC. - The Wiki
50. Fertilization targets : OVA
54. Word to a dog : SIC - Not SIT, BEG, and ROLL OVER did not fit
56. Compass dir. : ENE - WAGed ESE, since "S" is pretty popular at the end of crossword entries - made 29D a little tough to parse
57. Pop singer Quatro : SUZI
58. Thomas of old TV : MARLO - Nailed her, uh, I mean, it....
1. Procyon or Polaris : F-STAR - I am an amateur astronomer, I have an eight-inch...telescope (easy lois) - looking forward to April's night sky; most people know Polaris as the "North Star"; Procyon is in the constellation Canis Minor, down by Orion; Pollux is one of the "twins" of Gemini
2. Wishful words : I HOPE -....I am the winner of over a half billion dollars - then again, I would probably kill myself with the toys I KNOW I would be buying - amphibious planes, McLaren sports cars, etc. - of course, the Castle would come first....
3. It follows iodine in the periodic table : XENON - OK, I "cheated" - I have the periodic table app on my phone, so I looked - and it was not At, so it must be Xe
4. One-eighty : UEY - starting to get popular in CWs now....180°, U-turn slang
5. Will process : PROBATE
6. "Carol of the __" : BELLS
7. Squeeze : CRAM
8. Decorative vase : URN
9. Audio feeds : PODCASTS
10. Pilsner, for one : LAGER BEER
11. Like most wage earners, so they say : OVER-TAXED
12. Okra cross sections, e.g. : PENTAGONS - Image
14. Refrain syllables : TRA-LA
15. Team prankster's target, often : ROOKIE
22. Delivery aid : VAN
24. Sandwich choice : TUNA
25. 1930 winner of golf's Grand Slam : JONES (Bobby)
27. Find a new tenant for : RE-LET
28. Prepare to compare : JUXTAPOSE - always a great word
29. Bloomin' : Brit : __ : Yank : EVER-LOVIN'
30. Rocket scientist's industry : AEROSPACE
31. "Things" singer, 1962 : DARIN - singer Bobby - feel free to link away ~!!
34. Battle of Bull Run site : MANASSAS - last geography lesson
35. Wally __, whom Lou Gehrig replaced as Yankee first baseman : PIPP - I defer to our baseball and crossword blog host for this one (From C.C.: Pipp asked the day off because he had a headache. He later said "I took the two most expensive aspirins in history".)
37. Did a new mom's job : BURPED
38. Plain-woven fabric : GINGHAM - I did not know this was "this"
40. One of us : YOU
41. Parisian pops : PERES
43. Popular pop : PEPSI - personally, I prefer Dr. Pepper
44. Union site : ALTAR
45. Express alternative : LOCAL
46. Jerk : SCHMO
48. Contemporary of Collins and Mitchell : BAEZ - I thought I was clever, thinking this was an astronaut, like HAIZ (but I knew it was HAISE), since Michael Collins was in the capsule on Apollo 11, and Edgar Mitchell was on the moon for Apollo 14....nope....
52. Grand __: wine classification : CRU
53. Like : À LA