Leroy Chronomètre Observatoire for Only Watch 2015

By John Galt

The Only Watch auction occurring in Geneva in November has thrown a few surprises this time around with different manufactures coming up with some truly wonderful creations that will make extreme amounts of money for the cause. There is one watch that is not getting the exposure that I truly think it deserves as it is made entirely from aluminium, here is the Leroy Observatory Chronometer and it features a whole host of technical feats to improve the chronometer as we know it.


First let me explain the Observatory Chronometer. It has been built for excellent precision in its time-keeping and has been tried and tested by an observatory, in the case of Leroy it is the Besancon Observatory. Each and every Chronomètre Observatoire watch head (fully cased without strap) is tested comprehensively over a period of 15 consecutive days in every position and only then will it be given a certificate and individually numbered. The main-plate of the watch is hallmarked with a viper’s head which is only allowed for pieces that are tested and approved by the Besancon Observatory.


The case is 40mm in diameter, the perfect size for this dress type watch. The case is made of aluminium and has been treated to make it more resistant and harder than normal aluminium which Leroy have anodised to give a gorgeous anthracite colour. The Bezel has polished gadroons and has been circular satin-brushed. The aluminium dial is two-tone, lighter in the middle getting darker as you move to the outer edge which features a bold railway minute track. The hours are marked with applied Arabic numerals except at 6 O’clock where the numeral has been replaced with a dark grey sub-seconds dial that really stands out from the lighter aluminium dial. Small applied indexes filled with luminescent material are placed at 12, 3 and 6 but not 9, that is a power reserve indicator which blends in perfectly and doesn’t upset the clean aesthetics of the dial. The diamond shaped aperture reveals different colours depending on how much power is left. For 0-60 hours the disc remains the same colour of the dial, then for 60-80 it changes to white and beyond 80 it appears red to signal the piece needs winding.

Turning the piece over you are greeted by and exhibition case back that shows off the in-house and truly stunning finished calibre L200.


Turning the piece over you are greeted by and exhibition case back that shows off the in-house and truly stunning finished calibre L200.

The main-plate and bridges are made of aluminium in keeping with the rest of the piece. Everything is entirely hand-finished for instance: the pinion leaves are polished using only a wooden grinding wheel, he ratchet-wheels are finished using the Mât de Genève” process, which is an ancient decorative technique giving them a gorgeous anthracite colour. Other steel parts including the winding mechanism which is black polished; the bridges are bevelled and frosted to create a bronze-tone colour. All the screws are blued to avoid oxidation while the screw heads are specular-polished. Altogether the Leroy Chronomètre Observatoire watch is exquisitely finished and a real feast for the eyes.


I know this will not make the most money or set some of the buyer’s hearts racing in the auction but personally I think this is a shame as this is an exquisitely finished piece and made mostly in aluminium which is unique and I like it very much. For more info, please visit montres-leroy.com



John Galt caught the horology bug back in 2010 on his first visit to a London watch show and has snowballed since; John has become an avid writer and blogger of timepieces of all kinds, from everyday timepieces to modern Luxury HauteHorology, his favorite brands being HYT and GreubelForsey that push the boundaries of modern watch-making. John keeps a keen interest in the UK watch scene with their many emerging brands and timepieces. John Galt currently contributes watch related articles for online publications in the UK and USA. You can follow him on Twitter Read his articles here