This is a vintage Omega Constellation 168.004 with the very desirable Pie Pan dial. This particular watch dates to 1963. 
 
The watch has a large stainless steel case which measures 35.9mm in diameter excluding the recesses Omega crown. For its age, the case is in nice overall condition with some signs of wear. It has a screw down case back with the Observatory logo. 
 
The silver coloured dial is also nice for its age, showing some signs of wear. A very attractive look.
 
The automatic cal.561 movement is running well and keeping good time for a vintage watch. 
 
The watch has been fitted with a brand new leather strap with Omega buckle as well as a new crystal. It comes in a vintage Omega inner and outer box in very nice condition.