Horological Meandering

quattro · 2025-09-02T11:03:23Z

Observatory dials on precision watches pass tests at various locations. Many famous examples include Patek Philippe and Vacheron Constantin.

Observatory dial watches

What is commonly referred to as an "observatory dial" is the dial of a watch equipped with a precision movement, designed and adjusted to pass observatory tests, whether in Besançon, Neuchâtel, Geneva, Kew, Glashütte, etc.

Its most complete layout includes:

A small seconds subdial at 9 o'clock;

A sort of "subdial" at 3 o'clock with the name of the observatory where the movement was tested and the number of the Bulletin de Marche (certificate) it obtained.

But, as you will see below, there are many variations.

The most famous wristwatch with an observatory dial is the Patek Philippe reference 2458, made especially for Joe Ben Champion, Jr. (1917-1975), but I hope this thread will show that there are good reasons to look further.

Best,

Emmanuel

A/ TWO WATCHES WITH A COMPLETE OBSERVATORY DIAL LAYOUT by PATEK PHILIPPE and VACHERON CONSTANTIN

1/ PATEK PHILIPPE PLATINUM ref. 2458 made especially for J.B. CHAMPION - GENEVA OBSERVATORY BULLETIN NO. 861121

To discover the complete history of this now legendary watch, please check the following articles:

A Look At JB Champion's Unique Observatory Chronometer Wristwatch: The OTHER Patek With A Chance To Become The Most Expensive Watch In The World on Hodinkee

Historical PerspectivesThe True And Sad Story Of J.B. Champion, Jr., The Man Behind The Most Expensive Watch Without Complications Ever Sold At Auction by Eric Wind for Hodinkee

From $7,500 to $3.9 Million: The Most Expensive Watch I Ever Sold by Matthew Bain

The Lot Essay by Dr. Nathalie Monbaron for Christie's

For my part, I will limit myself to showing the watch with two elements that are generally left aside: the additional dial with diamond indexes and the platinum bracelet.

The watch

credit: hodinkee

The additional dial & the movement

credit: @strictlyvintagewatches

The watch with its platinum bracelet

credit: Matthew Bain

2/ VAHCERON CONSTANTIN KEW-TEDDINGTON OBSERVATORY 1918/1919 CHRONOMETER BULLETIN NO. 377635

credit: @artmgraver

B/ OTHER PATEK PHILIPPE EXAMPLES

1/ REF. 2556 IN YELLOW GOLD - movement number 861137 & case number 681113

The 3 o'clock "subdial" doesn't mention the observatory name, nor the Bulletin number.

This watch was purchased by Patek Philippe for its Museum at Antiquorum in 1990

credit: @positaque (1), personal photos (2-3), tp178.com (4) & Antiquorum (5)

2/ "CALATRAVA OBSERVATORY TYPE", No. 180729, steel case No. 611554. Produced in 1913, sold on October 10, 1935

Here, the brand name and location replace the observatory mentions.

credit: Antiquorum

3/ "CALATRAVA OBSERVATORY TYPE" with LUMINOUS DIAL , No. 122929, steel case No. 612619, Ref. 96 Produced in 1903, sold on February 5th, 1936

Same as above for the 3 o'clock "subdial", without the circle line.

credit: Antiquorum

4/ Ref. 96, movement No. 199139, staybrite steel case No. 610889. Movement made in 1921 and cased in 1934. Sold on September 3, 1934.

credit: Antiquorum

5/ STEEL POCKET WATCH NO. 89235

Here, the small seconds subdial is placed at 3 o'clock and the "subdial" with brand name and location at 9 o'clock.

credit: @ericmwind (1), @futuregrailofficial & @whitewhalewatches (two last photos)

C/ AUDEMARS PIGUET PRECISION WATCHES

Audemars Piguet has done several Precision watches equipped with cal. 13VZAS.

On the dial, the 3 o'clock "subdial" features the brand name, "Geneva" or the number of rubis and the word "Precision"

1/ NO. 45861 - pink gold & steel

NB: I have added another even more beautiful example with teardrop lugs here: The nicest AP Precision watch?

2/ NO. 46573 - yellow gold

3/ NO. 46582 - pink gold & stainless steel

credit: Antiquorum & Revolution (one before last only)

4/ NO. 46591 - steel

credit: Menta Watches & Roni Madhvani (last photo)

5/ NO. 46607 - pink gold

credit: antiquorum

6/ NO. 46618 - steel case with gold crown

This example was also sold by Christie's.

credit: Menta Watches

7/ NO. 46619 - yellow gold

credit: Antiquorum & Hodinkee

D/ MASSENA LAB & RAÚL PAGÈS WATCHES

1/ PHILLIPS IN ASSOCIATION WITH BACS & RUSSO 1952 OBSERVATORY DIAL LIMITED EDITION BY MASSENA LAB AND RAÚL PAGÈS

2/ ABSINTHE

Here, interestingly, the focus is clearly set on chronometry, with the words "Observatory" and "Precision" on the 3 o'clock subdial.

credit: Massena LAB

E/ EXAMPLES WITH ONLY A SMALL SECONDS SUBDIAL at 9 or 7 O'CLOCK (NO SUBDIAL at 3 O'CLOCK)

1/ PATEK PHILIPPE "M. BERTHAUDIN" ref. 96 CALATRAVA with OBSERVATORY TYPE DIAL - No. 122898, case No. 612616. Produced in 1903, cased in 1936, sold on February 5, 1936

Marcel Berthaudin was one of the largest wine dealers in Geneva. Note that the "R" of BERTHAUDIN lost its "leg" on the dial and looks like a "P".

credit: Antiquorum & @the_watch_adviser

2/ PATEK PHILIPPE "E. BONNARD" ref. 96 CALATRAVA with OBSERVATORY TYPE DIAL - No. 136786, case No. 612617. Produced circa 1930

Emile-Charles Bonnard was a French medical professor who retired to Switzerland and who requested this ref. 96 as a special order.

The "E. Bonnard" and "M. Berthaudin" together. To read more about these two watches, check the following article by Mark Kauzlarich on Hodinkee: Four + OneJohn Nagayama – Japan's Calatrava King

credit: John Nagayama aka @johnbehalf

3/ BERNHARD LEDERER TRIPLE CERTIFIED OBSERVATORY Central Impulse Chronometer 44, ref. CIC 9012.10.710

This watch, limited to 8 pieces, won the 2024 GPHG Chronometry Prize

Case: 44mm diameter x 12.2mm height – 904L stainless steel

On the lower surface of the small seconds subdial, three concentric decorative rings are engraved with the coordinates of the observatories where the watch has been tested for certification:

Nearest to the centre are the coordinates for the Observatoire Chronométrique in Geneva (46.19607 | 06.12930),

followed by the French Besançon Observatory in the middle ring (47.24875 | 05.98963),

and finally, the German Glashütte Observatory’s location (50.84780 | 13.78730) engraved closest to the edge.

credit: @watchesbylogan (1), @ch24pl, Monochrome (one before last) & Bernhard Lederer (last)

💰1729 Marketplace Listings for Patek Philippe›Omega Constellation · 1 for sale · 1516 discussions›

Great post with great photos! That VC sings to me!!

By: orahu : August 30th, 2025-13:10

Thank you, Orahu!

By: quattro : August 30th, 2025-14:03

Unfortunately, I have no further information concerning the history of this VC: when and for who this chronometer movement was fitted in such a case. I would have to ask @artmgraver (Shiming Yang) on IG. Best, Emmanuel

This is the Vacheron which surprised me the most. Re cased one?

By: amanico : August 30th, 2025-13:56

Yes, almost certainly cased later, like the Patek Champion and

By: quattro : August 30th, 2025-14:07

most other observatory movements. I believe many were never cased, just remaining as chronometer movements. But I have no further information on this VC: I would have to ask its owner, @artmgraver (Shiming Yang), on IG. Best, Emmanuel

...

Thank you! I didn't know these watches.

By: quattro : August 31st, 2025-11:57

I wonder what is the exact difference between chronometers and observatory watches. I would think that "chronometer" implies a COSC or METAS certification which might be a little different from an Observatory one... But it remains a bit unclear to me.

I think your guess is right.

By: amanico : August 31st, 2025-11:58

Here are some others...

By: amanico : August 31st, 2025-12:02

...

Wow, the Tourbillon is absolutely wonderful!

By: quattro : August 31st, 2025-15:09

Do you have the face of the MR?

Sure!

By: amanico : August 31st, 2025-17:51

This is this one: ...

Beautiful!

By: quattro : August 31st, 2025-21:07

Clearly!

By: amanico : August 31st, 2025-21:28

Great article Then there a whole lot of Rolex kew a models

By: watch-guy.com : August 31st, 2025-04:35

I wasn't aware of the Rolex Kew A pieces, to be honest.

By: quattro : August 31st, 2025-08:56

Thanks a lot for pointing them out to me. In a comment below, Carlos22 also pointed out the Roger Dubuis Bulletin d'Observatoire, which are interesting pieces as well. But what I was specifically looking after was this particular dial layout with small se...

Observatory dial watches

Observatory dial watches

Great post with great photos! That VC sings to me!!

Thank you, Orahu!

This is the Vacheron which surprised me the most. Re cased one?

Yes, almost certainly cased later, like the Patek Champion and

I think this is the case for some Observatory Longines, too...

It seems very likely !

Here it is:

Thank you! I didn't know these watches.

I think your guess is right.

Here are some others...

Wow, the Tourbillon is absolutely wonderful!

Sure!

Beautiful!

Clearly!

Great article Then there a whole lot of Rolex kew a models

I wasn't aware of the Rolex Kew A pieces, to be honest.

Yes, the Roger Dubuis! Even Kari, isn't it?

Yes, but the Voutilainen Observatoire don't bear any mention of

True!

Yes, but never saw one in real.

The owner told me on IG that he cased the movement himself

Interesting!

Fantastic!

Thank you! I'm glad you like the post!

Many of the first generation Roger Dubuis watches had Observatory certification

Great! I didn’t know. It’s definitely also an “observatory dial”.

Great post. I'd never heard of this type of watch before or seen one of them.

Thank you, Blansky. I'm glad if this post brings something new.

Might the PP and AP wristwatches be using the same ebauche?

Yes, I think they are all using the same Valjoux 13 VZAS caliber.

Thanks a lot for another fascinating post 👌🏻👍🏻

Thank you so much!

Agreed with both of those 👌🏻👍🏻

As usual great research and work behind the post, thanks a lot for taking time to share !

Thank you so much!