ochs line day/night


How long is it until sunrise? Is there enough daylight left for a little bike ride this evening? Where in the sky is the moon? The astronomical function by Ludwig Oechslin answers all of these questions. With day/night strapped to your wrist, the following information is available to you with a quick glance:

  • Length of day and nighttime for the location of your choice. This adjusts dynamically!
  • Solar noon
  • Sunrise and sunset
  • The position of the sun and moon in the sky
  • The moon phase, date and time.

Personalize your location

Your day/night watch will have a custom-made part which syncs it to your chosen location. Should you decide to change your place of residence in the future, we can easily install a new part to adapt the location for you.
Ludwig Oechslin’s day/night is available for both the northern and southern hemispheres.

Reading the functions

The video above shows an entire month in 3 minutes. A complete list of day/night’s functions can be found below.

Daytime and nighttime

The light and dark-colored areas around the dial show the length of day and night. The lines separating them represent the horizon. The horizon fans move up or down every 10 days to account for seasonal changes.

Sunrise and sunset

At sunrise, the sun passes from the darker colored area of the dial into the lighter colored area. At sunset, the sun passes from the lighter colored area to the darker colored area.

Moon phase

The center of the watch can be imagined as a representation of the earth. The moon’s position in relation to the sun indicates the moon phase. The moon is beneath the sun at a new moon, and the moon is opposite the sun at a full moon.

Solar noon

Using the pusher at 6 o’clock, solar noon (when the sun is at its highest point in the sky) can be set for your location (demonstration video).


The date indication at 6 o’clock is used to set the watch. The reason this watch does not feature a date spiral is that the dial holds gear wheels near the perimeter.

Sun and moon position

When facing south, the position of the sun and the moon on the dial indicates the direction in which you will find these heavenly bodies in the sky.


The following parts were designed by Ludwig Oechslin specifically for day/night.

  1. Hour wheel on hour pinion with friction
  2. Transition wheel 1 for moon and sun cogwheels
  3. Transition wheel 2 for moon and sun cogwheels
  4. Sun cogwheel
  5. Moon cogwheel
  6. Date disc
  7. Gear wheel between date disc and annual wheel
  8. Year wheel with crank pin in the size of the deflection of the horizon fans
  9. Carriage with cogs to move the horizon fans
  10. Horizon fan
  11. Horizon fan
  12. Module board
  13. Dial

The base movement for the day/night is the Swiss Made Ulysse Nardin UN-320.

Further information


40mm x 11mm (incl. crystal).


61g in titanium (incl. leather strap and buckle).

Water resistance

100m in titanium.


2-part case in grade 5 titanium designed by Ludwig Oechslin. Visible machining marks.

Base movement

Ulysse Nardin UN-320 with a power reserve of 48 hours. Manufacturer: Ulysse Nardin SA / Le Locle / Switzerland.


Screw-down crown designed by Ludwig Oechslin in grade 5 titanium.


In Grade 5 titanium designed by Ludwig Oechslin for 22mm watch straps with no loops. Visible machining marks.

Watch strap and leather pouch

Ecopell Enzian leather strap in S/M/L/XL and leather pouch handmade by Sabina Brägger.

Sapphire crystal

Sapphire crystal, both sides are treated with anti-reflective coating.

Swiss made

The ochs und junior day/night watch is manufactured in Switzerland. The base movement Ulysse Nardin UN-320 is produced in Le Locle / Switzerland. Each watch is hand-assembled decorated, and regulated at the ochs und junior workshop in La Chaux-de-Fonds.


The entire watch is covered by a 2-year guarantee.


Ludwig Oechslin and ochs und junior, La Chaux-de-Fonds, Non-customizable.


Orders can be placed by e-mail to [email protected] / [email protected] or directly on our homepage https://www.ochsundjunior.swiss

The watches will be delivered three months after the order date.

Order with a 50% prepayment in accordance with the ochs und junior standard guidelines: Payment via stripe, via credit card (saferpay) or via bank transfer (wise) to our bank account:

Credit Suisse, Schwanenplatz 8, CH-6002 Luzern
ochs und junior AG
IBAN: CH31 0483 5039 2684 4100 0
Clearing No. 4835
Account No. 0463-392684-41