Chronostop Part 4 - The Final Chronostop, Panerai PAM00078 Radiomir

It may be an unlikely place to end our series on the Omega Chronostop but the last watch based on this movement family was a Panerai, made in the year 2000, out of solid gold.

A Continuation of the Series

This is the final part of a 4-part series about the Omega Chronostop line.  For the first, second, and third parts, click the links below:

Chronostop Part 1 - Geneve Chronostop & Special Japanese Variants
This will be the first of four parts in our series on the Omega Chronostop, a model spanning many model lines and even brands with a complication so unusual that there is nothing in Omega’s modern product line that even compares.
Chronostop Part 2 - The Italian Geneve Pentatlon, Lemania Racing & De Ville
Our journey into the Chronostop model lines ventures into Italy with the Chronostop Pentatlon, also known as the Chronostop Fontana, and the little known Lemania & De Ville variants of this case design.
Chronostop Part 3 - Seamaster Fixed & Rotating Bezel Variants
The Seamaster Chronostop is the largest and arguably the most practical and useful of all Chronostop models with a suite of bezel options that bring new functionality, style and purpose to the model line.

But... That's Not an Omega

Correct, this is not an Omega, it is a Panerai Radiomir in 18K solid white gold.  

This watch was produced decades after the original production run of Omega Chronostop models and was produced in very small numbers.  Most likely the movements powering these Radiomirs were made back in the late 1960's or early 1970's and sat in storage until they were re-finished by Panerai for use in these watches.

The Panerai PAM00078 Radiomir - Image by

2001 was an interesting era for both Panerai and Omega.  Omega was back on its feet after a very successful rebuilding phase throughout the 1990's, and Panerai had only recently been purchased by Richemont group.  

Panerai at that time was still a case-maker and designer of watches, using third party movements from a variety of sources and had not yet moved to in-house calibres.  Some Panerai enthusiasts consider this era to have produced some of the best models, like the ETA 7750 based PAM00104, the El Primero based PAM00072 and the ETA 6497-1 based PAM00000.  The variety and quality of movement options was tremendous, and it was in this period that Panerai tapped Omega to borrow the Calibre 920 Chronostop movement to produce a very special solid gold Radiomir.

It's interesting to note that even on the Panerai website page for the PAM00078, they don't use a Panerai specific codename for the movement or call it a Lemania, but openly state that it is an Omega Calibre 920.  Panerai made great watches in this era and there was no shame in using a borrowed calibre, especially if it were good.

PAM00078 - Radiomir Seconds Counter - 42mm
Radiomir Seconds Counter - 42mm, PAM00078 Hand-wound mechanical Omega 920 of the 1970s, 10 lignes White gold with tachymeter scale engraved, Check availability on

The Door Remains Open for a Revival

Throughout this series, it has been repeatedly mentioned that the Calibre 865 and 920 are effectively a cut down and modified version of the Calibre 861 moonwatch movement.  It has also been mentioned that the Calibre 861 later evolved slightly into the Calibre 1861 before making a more significant jump to the current Co-Axial Calibre 3861 powering the latest generation of Speedmaster Professional.

The Co-Axial Calibre 3861 - Image by Omega SA

Based on the work that has already been done then, the possibility does remain that Omega could produce a Calibre 3865 or 3920 Co-Axial Chronostop movement at some point, modifying the latest calibre in the same way that the original was in the 1960s.  

Prices for Omega watches, and quality have increased drastically in recent years as have customer expectations.  But when we look at this 18K white gold Panerai, we can see the potential for an upmarket, modern Chronostop, perhaps even something also made from precious metal.  

Case & Strap

The case and strap of the PAM 78 are very special, as one would expect for a 1/75 precious metal watch of this price point.

The case follows Panerai's traditional Radiomir design with detachable thin wire lugs for strap changes.  It has a diameter of 42 mm and wears quite large thanks to the cushion style case of the Radiomir.  The case is primarily brushed, but features a polished bezel with tachymeter scale, similar to many models of Omega Chronostop.  

The case features a very impressively implemented display-back, which shows off the spectacularly finished Panerai treatment of the Omega Calibre 920 movement.

Something that will confuse non-Panerai enthusiasts is that the case-back has a 12-sided keying for a case-back opener as it uses a screw-in mechanism, yet there are also four screws in the corners surrounding it.  These screws are actually not related to the case-back, but are used to secure the wire lugs.  When changing straps, you would use a screwdriver to remove the four screws, pull the lugs off the case, swap the strap over then re-insert the lugs and secure them again by replacing the screws.

The case features the single pusher we would expect on a Chronostop at the 2 o'clock position, and a traditional Radiomir style large, knurled crown, with no crown-guards.  The case carries a depth rating of 100 meters but the pusher should not be operated when submerged.

Being made from 18k solid white gold in a fairly blocky case, there is a fairly significant amount of weight in the head, and many used examples have collected some dents and dings as a result of that combined with the soft metal.  

The wire lugs are 24 mm width, and are the strap is secured with an 18k white gold vintage style tang buckle.


The movement in this Panerai may be based on the Calibre 920, but Panerai have gone to great lengths to heighten the finishing quality in order to make the movement distinctly theirs and attractive to admire through the display-back.

The most obvious difference is that the traditional Omega copper colored plating is gone, replaced with rhodium plating and decorated with Côtes de Genève stripes on every plate.  Blued screws are also added, and all mention of Omega is removed, with Officine Panerai being engraved in gold on the main chronograph bridge.  

As mentioned in part 1, the Calibre 920 is derived from the highly regarded Calibre 861 movement found in the Speedmaster Professional Moonwatch.  The family has proven over many decades to be highly reliable, accurate and maintainable, with the latest Calibre 3861 Co-Axial movement powering the current Moonwatch still based on the original Cal 861 design.

The Calibre 920 is manual wind, beats at 21,600 vph and lacks both hacking and quickset date.  The calibre is not chronometer rated, however when serviced correctly can reach quite good levels of accuracy.  Being derived from the Calibre 861, the chronograph mechanism found in these movements is a cam and lever design. It differs here from the 861 in that there is only a single pusher for all three functions rather than two.

This means that the same pusher will function in the order Start -> Stop -> Reset before starting again on the fourth press.  This also means that once the chronograph has been stopped, there is no re-starting it without resetting first as the sequence is dictated by the position of the cam with a single pusher configuration.

The undecorated Omega finished Calibre 865

Due to the value of these watches, and how few of them were made it is definitely best to send these back to Panerai for service.  The parts used on the Panerai differ enough from the Omega so greatly aesthetically that there really is no alternative to a factory service, especially if any parts are required.

Dial & Hands

The dial on the PAM00078 is large, legible, and quite nicely finished.  

It features large, luminous Arabic hour markers at 12, 9, and 6, date at 3, and applied luminous baton markers for all other hour markers.  The top of the dial has the text RADIOMIR PANERAI while SECONDS COUNTER is written at the bottom, Panerai's own name for a Chronostop.

The hands used are traditional white gold Panerai stick hands with luminous inserts for hours and minutes, and with a luminous arrow-tipped seconds hand.  The outer seconds track is unusual in that it uses half second increments rather than sub-seconds to match the movement.  There are 5 second Arabic indices on the seconds track in mid-blue which really looks great and gives the watch a subtle hint of color.

The lume on the PAM 78 is Super Luminova, as indicated by the L SWISS MADE L at the bottom of the dial, and the application is very generous, giving excellent legibility in the dark, a hallmark of Panerai watches.

Lume shot of the PAM00078 - Image by

The date wheel is unique to the Panerai, with a very different font from Omega versions and is white with black text.  Panerai goes to the trouble of adding a magnifier to the sapphire crystal, which is a nice touch and makes the date much easier to read than on other Chronostops.


These Panerai models are very rare, with only 75 produced for the entire world and with being 18k solid white gold, they were expensive watches when they were initially released over two decades ago.

The Panerai market has definitely cooled greatly in recent years, particularly as some popular limited editions were effectively re-released with minor changes.  This never happened with the PAM78, and no other model of Panerai ever carried the Omega Chronostop movement besides this reference.

The most recent price reference at auction is a watch sold at Phillips in May of 2022 for 21,420 CHF, which seems quite reasonable considering the rarity and quality of the watch on offer.  Dealer and private seller prices are quite a bit lower, anywhere from $12,000 to $16,000 which is definitely reasonable for a precious metal Panerai of this calibre.

While it isn't an Omega, and isn't even an in-house Panerai, it is impossible to not recognise these Radiomirs as the ultimate and most desirable watch to ever carry a Chronostop mono-pusher movement.  That is at least, unless Omega decides to try their hand at the Chronostop again with a Co-Axial escapement at some point in the years to come.

Discussion thread on Omegaforums can be found here:

Chronostop Part 4 - The Final Chronostop, Panerai PAM00078 Radiomir
[IMG] It may be an unlikely place to end our series on the Omega Chronostop but the last watch based on this movement family was a Panerai, made in...