Here is a rare Omega Constellation Automatic Calendar watch. This watch is one of four, 1st generation "Constellation Calendar" model, having a total quantity of only 25,000 pieces manufactured with a 24 jewels Omega caliber 504 movement. It has been fully serviced and running accurately. The movement serial number is 16889287, dating this watch to 1958. Attractive factory original finish dial in great condition. Original signed crown. Brand new crystal--- slightly used original vintage 18mm genuine leather strap (not original Omega). The unpolished solid stainless steel original case measures 35mm, excluding the crown by 44mm lug tip to lug tip. Case model 2943-5 SC. The calendar feature is working accurately. The wrist size in the photo is 6 inches.