Vintage Omega Constellation Chronometer

You will find a constant source of pleasure in the perfected beauty of a Vintage Omega Constellation. Its subtly curved case, its discreet luxury, its superb finish, the richness of its matching bracelet, and of course its magnificent accuracy… all this makes a Vintage Omega Constellation a lasting enjoyment.
And this is only the outside! One of the inner secrets of the Vintage Omega Constellation is its self-winding movement. Every gesture sends a surge of power to the mainspring, keeping it at the constant full tension that contributes to the astonishing precision of the watch. Another advantage of this steady 'winding*… it have it powered it for almost two days off-the-wrist timekeeping.
In addition, a Swiss chronometer. The title of chronometer awarded by an official Swiss Institute. To qualify, the Constellation was put through a rigorous non-stop 360-hour test. In heat and cold alternately. Its running was minutely checked in different positions. Throughout, it must keep an almost perfect regularity. But following the trial… the triumph.
Every Omega Constellation chronometer was awarded its title with the coveted highest mention 'especially good results'.

One of the best online resources on this subject is the Omega Constellation Collectors blog by Desmond.