• cal. 17-250 QP photo-electric mechanical movement, Gyromax balance, 29 jewels • rhodium-plated dial, painted elongated baton indexes radiating from an eccentric point, apertures for day, date and month in English • gilt brass rectangular case • movement signed by maker, dial signed by maker and retailer 

The movement is running at time of cataloguing, however it was not tested for the accuracy of time or duration of the power reserve and may need service at the buyer's discretion. Please note that Sotheby's does not guarantee the future working of the movement. Case in overall very good vintage condition with surface wear, very light scuffs and indentations consistent with age and moderate use. Solar panel at the top of the rectangular case as a small interior fracture at the lower left corner. Dial in very good condition with some surface wear to the edges of the calendar apertures. An round impression from the back side of the dial is apparent at the lower left hand corner of the rhodium plate. Movement in excellent condition.
"In response to your inquiry, we are pleased to provide you with a general report of the condition of the property described above. All dimensions in catalogue descriptions are approximate. Condition reports may not specify mechanical replacements or imperfections to the movement, case, dial, pendulum, separate base(s) or dome. Watches in water-resistant cases have been opened to examine movements but no warranties are made that the watches are currently water-resistant. Please note that we do not guarantee the authenticity of any individual component parts, such as wheels, hands, crowns, crystals, screws, bracelets and leather bands, since subsequent repairs and restoration work may have resulted in the replacement of original parts. Since we are not professional conservators or restorers, we urge you to consult with a restorer or conservator of your choice who will be better able to provide a detailed, professional report. Prospective buyers should inspect each lot to satisfy themselves as to condition and must understand that any statement made by Sotheby's is merely a subjective, qualified opinion. Prospective buyers should also refer to any Important Notices regarding this sale, which are printed in the Sale Catalogue. In particular, please note it is the purchaser's responsibility to comply with any applicable import and export matters, particularly in relation to lots incorporating materials from endangered species.NOTWITHSTANDING THIS REPORT OR ANY DISCUSSIONS CONCERNING A LOT, ALL LOTS ARE OFFERED AND SOLD AS IS" IN ACCORDANCE WITH THE CONDITIONS OF BUSINESS PRINTED IN THE SALE CATALOGUE."

**Please be advised that bands made of materials derived from endangered or otherwise protected species (i.e. alligator and crocodile) are not sold with the watches and are for display purposes only. We reserve the right to remove these bands prior to shipping."

Accompanied by an Extract from the Archives confirming sale on October 7th, 1968. Together with a Patek Philippe presentation box. 

Patek Philippe began developing photo-electric technology before 1950, a cutting edge technology not yet mass produced for the retail market. The technology was so innovative for civilian use that in the 1960s, Patek Philippe’s promotional literature for these timepieces noted explicitly their influence from the solar panels used to provide energ⛄y for the cameras aboard NASA's robotic Surveyor space crafts.

The result of seven years of research and development, Patek Philippe's photo-electric clock was not only among the first civilian uses of solar power, but the first application of this technology in any horological piece. It was also the first freestanding, portable timepiece operated by means other than a traditional mechanical movement. Along with the advent of the electromechanical and quartz movements, this solar-powered milestone was one of several significant advances in the third quarter of the 20th century that threatened to render mechanical moܫvements obsolete.

The photo-electric movement on the present example functions by a combination of several different mechanical proces𒈔ses. The upper solar panel collects artificial or natural light, which is transmitted🌠 via wires to a battery. This energy is then used to adjust the calendar wheels and wind the mechanical cal. 17-250É movement.

This movement is particularly interesting for its allusions to Patek Philippe's more traditional work. Cal 17-250É is a variation of the watch movement cal. 17-250, and is distinguished by three major differences. The first is that꧒ cal. 17-250É is rendered in gilt metal rather than nickel-finished metal. Secondly, the 🎉wheels of the gear train on the present example are noticeably larger than they would be in a watch movement. Third, and most interestingly, is in the layout. Cal. 17-250É features a gear train that has been separated from and housed adjacent to the main movement plate. This unusual configuration places the wheels directly in front of the torque device that acts as a winding mechanism.

A similar clock is in the Patek Philippe museum, and in the museum book, 2004 ed♈ition, volume 2, page 🌃399.