iwc PORTUGIESER PERPETUAL CALENDAR Mode D'emploi page 21

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Moon phase display
1 2 3 4
Full moon Waning moon New moon Waxing moon
The moon phase display is automatically set by the calendar so that it is al-
ways correct. The transmission ratio is so precise that the display deviates by
only a single day after 577 years.
Setting the calendar
Pull out the crown to position 1. In this position, you can use the rapid-advance
function to move the calendar forward one step at a time by turning the crown
slowly to the left. The calendar must not be adjusted between 8 pm and 2 am.
Please note:
You must not move the calendar beyond the correct date. The complicated
movement is mechanically programmed and cannot be moved back in time
without making a professional adjustment to the movement. However, if you
do move the date forward beyond the correct date, you have two options: you
can either pull out the crown to position 2 to stop the movement until the cal-
endar setting once again matches the correct date. This makes sense if the
date has been set only a few days ahead. Or, you must take your watch to your
watchmaker, who will be able to adjust the movement to reset the calendar.
This is recommended in the event of larger maladjustments.