STRÖMGREN OG OLSEN | A RARE AND INTERESTING GOLD OPEN-FACED ASTRONOMICAL DECK WATCH WITH INDICATIONS FOR SIDEREAL TIME AND EQUATION OF TIMECIRCA 1920, NO.557

• Movement: gilded unsigned, lever escapement, jewelled to the centre, wolf's tooth winding, bi-metallic compensation, swan-neck regulation, plain polished gold cuvette• Dial: white enamel, outer ring for minutes and equation of time with Arabic five-minute markers, three sunken subsidiary dials for mean-time hours, sidereal 24-hours and subsidiary seconds, two central hands in gold with sun terminal for mean-time minutes and blued steel Breguet hand for sidereal minutes, marked patent and signed and numbered Strömgren Og Olsen, no. 557 • Case: 18ct gold case, polished covers, gold pendant and bow

Sotheby's New York, Fine Watches from the Atwood Collection, 11 December 1986, lot 352

Movement - running at time of cataloguing. Dial: very faint scratch running from dial edge just above '40' to the mean-time hours - this does appear to be a scratch rather than a hairline but it is not possible to be certain. A few small scratches. Case: lightly polished, covers close securely
"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."

Dr Svante Elis Stromgren (1870-1947), Professor of Astronomy at Copenhagen University, collaborated with the Danish watchmaker Jens Olsen (1872-1945) to create the display shown on this watch. The watch is made according to Olsen and Stromgren's patent which was first registered in Germany in 1914 (no.283094), followed by Switzerland in 1915 (no.73312), U.S.A. in 1916 (no.1187110) and Denmark in 1918 (no.22822). The display of mean and solar time is most unusual. Rather than incorporate a separate dial for sidereal time or a separate display for the equation of time within a subsidiary dial or sector, showing simply the difference in minutes + or - between solar and mean time, this watch has two concentric minute hands allowing both forms of time to be shown simultaneously upon the same dial using the same minute calibrations. As the watch runs, so the minute hand for sidereal time will advance ahead of or fall behind the mean-solar minute hand, thereby reflecting the actual difference in time between the two. The two central minute hands may be advanced in tandem or separately - by depressing the crown, the hand setting may be placed into either tandem or single setting and the hand or hands moved using the hand-set pusher and crown in the usual manner. This rapid form of adjustment allowed the watch to be quickly and conveniently set.