1990 Longines Ephemerides Solaires 5235
This 37mm watch has an ETA 2824 as a base caliber, but it also includes a sunrise/sunset complication (yes, I know we just said that the AP Jules Audemars Equation Of Time was the first; more about that in a minute) at 12:00 on the dial, and an indication of the solar declination: This is the angular difference between the path of the Sun in the sky and the celestial equator. The declination is zero on the equinoxes, and reaches a maximum angle of 23.44 degrees on the solstices, and you can see that the indication for solar declination shows a maximum declination of 24 degrees (a reasonable approximation given the tiny size of the indication's aperture).
The Equation Of Time is shown by the blue line on the rotating bezel, which has a conspicuous locking lever at 6:00 (why, I'm not sure, as the position of the blue line doesn't change; maybe it's intended to keep the bezel locked so that the current month is at the top of the dial), and you basically just read off the approximate Equation Of Time for the day to within whatever resolution your vision is capable of – assisted, perhaps, by a magnifying glass. One owner of this watch mentioned on Timezone.com, in 2001, that he definitely needed one to read off the sunrise/sunset complication. The month and date are shown in apertures on the left and right respectively.
How to read off sunrise and sunset times is less obvious. Instruction manuals for this watch do not appear to have made it online (which is not surprising given the date of manufacture and the small number of watches made – 1,000 in stainless steel and 200 in gold, according to the gent on Timezone), and indeed, a search for the manual turns up several plaintive requests from new owners of pre-owned Ephemerides Solaires watches asking if anyone has one. As far as I can tell, the hour of sunrise and sunset is given by the position of the boundary between the blue and gold sections of the respective indicator rings along the bottom of each sector. In the watch in the picture, the date is August 2. The sunrise/sunset times are calculated for St. Imier, Switzerland, which is the historic home of Longines and, indeed, the time of sunrise on August 2 in St. Imier was 6:13 AM – the watch shows 5:13, but this doesn't take into account European Summer Time, which adds an hour. What the 1-15-30 graduations might mean is less clear to me – possibly the time difference between actual sunrise and sunset, and twilight, which is about 20-30 minutes; I'm not sure how you'd read that off from the indications though.
- HODINKEE
Information:
Limited: 1000 Pieces
Reference: 5235
Dated: 1990
Case: 37mm x 10mm Thickness - Stainless Steel
Strap: Original Brown Leather Strap
Lug Width: 19mm
Movement: ETA 2824 base - Automatic
Functions: HMS, Date, Month, Sun Runway Complication
Box and Papers: No box, yes warranty card
Crystal: Acrylic
Bracelet size: 7.5”
Condition:
Case has light normal micro wear. Strap has moderate wear with some creasing and loss of leather. Dial, hands, and crystal have no wear. Watch runs within spec.
History of Longines Watches
Longines, founded in 1832 by Auguste Agassiz in Saint-Imier, Switzerland, started as Raiguel Jeune & Cie. In 1846, Agassiz's nephew, Ernest Francillon, joined the company, bringing innovations like crown-wound pocket watches that positioned the company at the forefront of watchmaking technology. In 1867, Francillon established the company's first factory in Saint-Imier's "Les Longines" and introduced the 20A movement, earning accolades at the Universal Exhibition in Paris. Francillon's strategic move to industrialize production and Jacques David's technical direction were pivotal in shaping Longines' future as a leader in Swiss watchmaking.
The late 19th and early 20th centuries saw Longines pioneering in sports timing with the development of its first chronograph movement in 1878 and becoming a primary supplier for New York sporting officials by 1886. The company's trademark winged hourglass logo, registered in 1889, remains the oldest unchanged active trademark with the WIPO. In the 20th century, Longines adapted to the rise of aviation, creating iconic watches like the Weems Second-Setting Watch and the Hour Angle watch. The mid-20th century brought advancements like the Chronocinegines and the company's first quartz movement. Today, under the Swatch Group, Longines continues to blend its historical heritage with modern design, producing elegant and precise timepieces while maintaining its long-standing connection to the world of sports.
