How to set up the Jaeger-LeCoultre Master Ultra Thin Moon (calibre 925)
Short answer: Press corrector B at 8 o'clock until the full moon is centred, then once per day since the last full moon. Press corrector A at 4 o'clock to move the date a day at a time. Set the time with the crown pulled to position 1, where the seconds stop.
Jaeger-LeCoultre Master Ultra Thin Moon (calibre 925) at a glance
| Calibre | 925, automatic, about 70 hours, 28,800 vibrations per hour |
|---|---|
| Crown | 0 = winding (doesn't lock when full), 1 = time with stop-seconds |
| Correctors | A at 4 o'clock = date. B at 8 o'clock = moon. |
| Date | Shown by a hand |
| Water resistance | 5 bar |
What do you need to set on the Jaeger-LeCoultre Master Ultra Thin Moon (calibre 925)?
Set up moon phase on the Jaeger-LeCoultre Master Ultra Thin Moon (calibre 925)
N is the number of whole days since the last full moon. The interactive guide works it out for your location and today's date, and shows the exact count.
- 1
Hands out of the night window
Our precaution, not a manual rule: set the hands to around 14:00 first, away from the overnight date change.
⚠️ Avoid 21:00–03:00 on the dial. This is our general precaution for calendar watches, not a JLC instruction.Generic step Confirm this in your manual. - 2
Corrector B (8 o'clock): to FULL
Each press jumps the disc one day. Press until the full moon is centred.
🎯 Full moon centred - 3
Corrector B: N more presses
One press per day since the last full moon.
Set up the date on the Jaeger-LeCoultre Master Ultra Thin Moon (calibre 925)
- 1
Corrector A (4 o'clock)
Each press jumps the date one day.
⚠️ Avoid 21:00–03:00 on the dial. The date and moon mechanism is engaged then. Move the hands out of that window first (for example to 6:30), or wait.
Set the time on the Jaeger-LeCoultre Master Ultra Thin Moon (calibre 925)
- 1
Crown to position 1
The movement stops (stop-seconds).
- 2
Move hands clockwise
Set the time, push in at the stroke of the minute.
Start a stopped watch on the Jaeger-LeCoultre Master Ultra Thin Moon (calibre 925)
- 1
A few turns of the crown
Crown in position 0. Turn clockwise. It doesn't lock when full.
What owners run into
- The crown doesn't stop you when the watch is fully wound. A few turns is all it needs if it has stopped.
- Mixing up the correctors: 4 o'clock is date, 8 o'clock is moon.
- The JLC manual has no night-time warning for the correctors. We still suggest putting the hands at around 14:00 first, as a general precaution on calendar watches.
How the Jaeger-LeCoultre Master Ultra Thin Moon (calibre 925) differs from similar watches
Correctors like the Omega 1866, but the Omega manual forbids 7–12 o'clock while the JLC manual sets no window. Unlike the Longines L899, nothing here is set with the crown except the time.
Quick answers
Which corrector sets the moon on the Master Ultra Thin Moon?
Corrector B at 8 o'clock. Corrector A at 4 o'clock sets the date.
How long does the JLC 925 run when off the wrist?
About 70 hours.