ochs und junior moon phase "blue dial" in 39mm & 42mm

Described by one journalist as perhaps the most accurate moon phase available, we would like to share with you the newest addition to the ochs line, the moon phase / selene. The ochs line moon phase / selene comes in our exclusive ochs blue with rhodium plated markers, hour and minute hands, and full moon. The new moon is patina. The second hand is ochs blue.

Less is more

A moon phase watch, by definition, is complicated. But Ludwig Oechslin has always taken a different approach. While a typical moon phase complication is made up of countless pieces, the ochs line selene / moon phase module requires just 5 additional parts.

Ludwig Oechslin’s moon phase watch displays the time, the date, and of course the phases of the moon. It features a unique moon phase function executed as a 5-part epicyclic gear system module that will be accurate for 3,478.27 years before its calculation will be off by 1 day. The analogue, spiral “dot date” indicator offers a better visual que than a digital display from the same distance, and brings the date in visual harmony with the clockwise display of the hours and minutes.

Moon phase

The center represents the earth and the large dot at 12 o’clock represents the sun. The full moon is when the moon is opposite the sun and earth at 6 o’clock. The new moon is when the moon is hidden between the sun and the earth at 12 o’clock. The new moon is represented by a dark circle at 6 o’clock.

Date

The 30+1 holes around the perimeter of the dial display the date. The 10 minute markers serve as reference points. For example: the marker indicating 30 minutes also shows the 15th day of the month (30÷2=15). These 5-day markers allow for the date to be easily read at a glance. While it is a departure from a typical date function, reading it becomes intuitive after a short time.

Time

The exact minute and second can be read using the date holes, which are spaced at 2-minute intervals. The holes mark even minutes, and the gaps indicate odd minutes. The holes and gaps are the same width as the minute hand.

How does Ludwig Oechslin’s moon phase work?

An epicyclic gear train driven by a central finger bonded directly to the hour pipe turns the lunar disk beneath the dial counter-clockwise. The central finger engages with a wheel bearing 12 teeth, whose pinion with 14 teeth meshes with a wheel bearing 18 teeth, whose pinion with 14 teeth meshes with the fixed recessed ring gear with its 109 teeth machined into the underside of the dial (annotated diagram).

What is the benefit of a highly precise moon phase calculation?

The average time between two identical moon phases is 29.530589 days. Most moon phase watches approximate a lunation as 29.5 days, which leads their calculation to be off by 1 day after 2 years. The closer your moon phase calculation comes to the average lunation of 29.530589 days, the “flatter” the difference between your prediction and the actual moon phase. The ochs und junior moon phase calculates the lunation as 29.5306122449 days. As a result, it will predict the moon phase correctly for 3,478.27 years before it is off by 1 day. This means that you only have to set your moon phase once, and you can trust that it will accurately display the phases of the moon.

Technical specifications

ochs und junior ochs line moon phase or selene 39 mm / 42 mm

Case

• Material: Grade 5 titanium
• Diameter: 42 mm & 39 mm
• Thickness: 11mm
• Glass: Sapphire crystal
• Screw-down crown in grade 5 titanium
• Water-resistant to 100 meters

Weight

• 42mm titanium: 70g (incl. leather strap and buckle)
• 39mm titanium: 62g

Dial and hands

• Blue dial with rhodium plated markers, hour and minute hands, and full moon
• The new moon is patina
• The second hand is ochs blue
• Superluminova in blue

Movement

• ETA 2824-2 with 38 hours of power reserve.

Functions/Indications

• Hours, minutes, seconds, date
• Moon phases

Strap and buckle

• Ecopell Enzian leather strap with no loops
• Grade 5 titanium with visible machining marks

MSRP

• CHF 5'500 (incl. taxes)
• CHF 5'077 (export price)

For more information, please visit ochsundjunior.swiss