Hi all, having become recently obsessed with these I've gone through all 58 pages of this thread to begin my homework. Figured I'd share my notes so far to help compile a lot of this information in one spot. Maybe I'll put some of this stuff on my website one day. It would be nice to have it with images but I'd have to get permission from folks before doing anything like that.
I want to thank
@kaplan who has shared so much information here. All I've done is compile some links and tidbits. I did not even attempt to compile info on dial and case material variations. Please let me know if anything below is incorrect so I can fix it.
I also want to thank Desmond who runs the invaluable Omega Constellation Collectors website. I know he's a member here but sorry I don't know his username.
Thanks all for the resource!
## C-Case Constellation
Approximate Dates of Production: 1965 - 1978
Dimensions: 35mm diameter; 11mm thickness
Lugs: 19mm
Lug-to-Lug: ??? I think I saw 49mm somewhere.
Water Resistance: 30 meters
Material Codes: BA is solid gold, CD is yellow gold capped, CE is pink gold capped, ST is steel
### Serial Number Ranges for Approximate Dates of Production
1965: 22,000,000 – 22,999,999
1966: 23,000,000 – 23,999,999
1966: 24,000,000 – 24,999,999
1967: 25,000,000 – 25,999,999
1968: 26,000,000 – 26,999,999
1968: 27,000,000 – 27,999,999
1969: 28,000,000 – 31,999,999
1970: 32,000,000 – 32,999,999
1971: 33,000,000 – 33,999,999
1972: 34,000,000 – 34,999,999
1972: 35,000,000 – 35,999,999
1973: 36,000,000 – 36,999,999
1973: 37,000,000 – 37,999,999
1974: 38,000,000 – 38,999,999
1975: 39,000,000 – 39,999,999
1977: 40,000,000 – 40,999,999
1978: 41,000,000 – 41,999,999
Source - MillenaryWatches.com
### Reference Numbers
#### December 1964 through Mid-1966
-
168.008 cal. 561: Date only - Can't find much specifically about this reference.
-
168.009 cal. 561: Date only - smooth steel bezel. Sometimes double stamped with 168.017. First reference of the c-case that probably only has a smooth bezel and caliber 561. -
OVA - 1966 - BA 168.0009=168.017 /
Omega Vintage Archives - 1967 - ST 168.0009=168.0017
#### Mid-1966 through ???
-
168.017 cal. 564: Date only - smooth steel bezel -
Omega Vintage Archives - 1967 - ST 168.0017
-
168.027 cal. 564: Date only - fluted/knurled bezel (sometimes white gold bezel, steel bezel examples tend to show rust). -
Omega Vintage Archives - 1966 - ST 168.0027
#### Late 1967 - 1972
Later "transitional" examples of the 751 introduced the new "Constellation" script lettering with straight a "n" as opposed to previous curly "n".
-
168.019 cal. 751: Calendar(Day)/Date - smooth bezel -
Omega Vintage Archives - 1966 - BA 168.0019 /
Omega Vintage Archives - 1966 - ST 168.0019
-
168.029 cal. 751: Calendar(Day)/Date - fluted/knurled bezel-
Omega Vintage Archives - 1967 - CD 168.0029 /
Omega Vintage Archives - 1967 - ST 168.0029
#### 1972 - 1978
Dial script changed considerably. Applied Omega lettering moved to 6 o'clock position. New bezel introduced.
-
168.0056 cal. 1011: Calendar(Day)/Date -
Omega Vintage Archives - 1972 - ST 168.0056
-
168.0057 cal. 1021: Calendar(Day)/Date -
Omega Vintage Archives - 1972 - ST 168.0057
Note: The Omega Vintage Archives are allegedly known to contain inaccurate information.
BA is solid gold, CD is yellow gold capped, CE is pink gold capped, ST is steel
### Calibers
-
Omega 561: automatic, 24 jewels, date, chronometer - circa 1958-1967
-
Omega 564: automatic, 24 jewels, quickset date, chronometer - circa 1966-1969
-
Omega 751: automatic, 24 jewels, day, quickset date, chronometer - circa 1967-1970
-
Omega 1011: automatic, hacking, 23 jewels, quickset date, chronometer - circa 1972-1984
-
Omega 1021: automatic, hacking, 23 jewels, quickset day and date, chronometer - circa 1972-1984
### Bracelet
Standard OEM bracelet is a 1040 brickwork style with 518 end-links. It's probably worth paying a bit more to get a watch with the bracelet and end-links included instead of finding them separate.
"Honest advice: Don't buy 3rd party bracelets or go after makeshift end-links, it's a money pit - in the long run just buying the 1040's make sense no matter how much you pay." - Kaplan
1040 fits 518, 593, 539 end-links, and maybe more. Very few bracelets only fit a single end-link type.
Here's an example of 3011/518 on my 168.029. I like this design, it's very comfortable and the look is more "up market" than 1040. I like 1040 too, don't get me wrong. New 3011/518 is 450€ according to my OSC, so in line with the £390 quote.
### Random Tidbits
I believe all of the below remarks are from the esteemed Kaplan but a couple may have been from others.
(August 2022) "It's the best time to buy one, but 168.019 and 168.027's are much much less common, so if you want gold, 168.029 is an easy target, the sanest option is Closer (ebay seller) from Japan and paying around $1000 - keep in mind that they declare the full value, so it's like +20%" - Kaplan
"You can find a 168.017 in 1-2 months, but you'll likely spend 1-2 years for a 168.027" - Kaplan
"You can get a 168.029 around $500-700."
SpiralWinder offers aftermarket display casebacks.
Sapphire Exhibition Caseback for 1960s Vintage Seamasters and Constellations
Sapphire Exhibition Caseback for 1970s Vintage Seamasters and Constellations
### Sources
The C-Cased Constellation Thread at
OmegaForums.net
The Constellation C-Shape Watch: Omega's Child of the Sixties
It's All About MOY, Except When it Isn't
Omega Enthusiast YouTube Video - C-Case 101