H. Moser & Cie , Endeavour Perpetual Moon Rose Gold
This is an exceptional watch with a moon phase display which deviates only by a single day after more than 1,000 years. It displays the moon viewed from the northern hemisphere. The phases indicated on this watch are marked in a unique way and can be set to the minute, read and predicted. One orbit of the moon around the earth, after which the moon resumes the same position in relation to the sun, lasts for 29.53059 days on average. To be more exact: 29 days, 12 hours, 44 minutes and 2.9 seconds. The complicated gear train of the Perpetual Moon translates this interval so precisely that the resulting deviation is only 0.23 seconds per day. Or a whole day after 1,027.30 years.
In order to achieve the extraordinarily high display accuracy, the moon disc must be securely attached to the hour indicator and run with it continuously.