Longines Ephemerides Solaires Ref. 5235

The Longines Ephemerides Solaires is a rare, complex timepiece released in 1989 to celebrate the 100th anniversary of the registration of the Longine trademark logo. It is known for being a "technical tour-de-force" from the post-quartz crisis era, specifically designed to track the movements of the sun.

Key Features & Complications

The watch features an elaborate array of astronomical complications that are rarely seen together:

• Equation of Time: Displayed on a revolving bezel via a blue curve, this shows the difference between solar time and mean time (ranging from +15 to -15 minutes).

• Sunrise and Sunset: Two small windows at 12 o'clock display the times for these events.

Solar Declination: A window at 6 o'clock indicates the sun's position north or south of the equator, which can help in identifying latitude.

• Calendrical Data: It includes windows for the date (at 3 o'clock) and the month in Roman numerals (at 9 o'clock).

• Locking Bezel: The rotating bezel, used to calculate the equation of time, features a locking lever located at 6 o'clock to prevent accidental movement.

Technical Specifications

• Movement: It uses the Longines Calibre L 640 automatic movement, which is a modified version of the ETA 2834-2. The standard day function of the base movement was replaced to drive the astronomical complications.

• Power Reserve: Approximately 44 hours.

• Case Dimensions: Typically 37mm in diameter.

• Dial: Features a clean white enamel dial with black
Arabic numerals and blued steel hands.

Production & Availability

This model was produced in a strictly limited run:
• 1,000 units in stainless steel (Reference 5235).
•
200 units in 18k yellow gold (Reference 5234).