Omega has been making the Constellation for more than 70 years, a watch that was the Swiss brand’s elegant flagship timepiece before the Speedmaster landed in 1957. It got its moniker from an image on its caseback—an observatory beneath eight stars. The stars symbolized two chronometer records and six first-place precision awards that Omega earned between 1933 and 1952, the year the Constellation launched.

But Omega’s new Constellation Observatory collection has a completely new procedure for measuring accuracy, one that gets around the thorny issue of these pieces having no seconds hand.

Why should a seconds hand matter? Watches are tested for accuracy with photographic tracking of the seconds hand over a period of time. Having no seconds hand makes this impossible. The Constellation Observatory pieces, however, grant Omega some watchmaking history as they are the first two-hand watches to achieve Master Chronometer certification without a seconds hand.

Traditional testing by COSC—the Swiss body that certifies the accuracy of Swiss watches—uses photographic tech to measure the position of the hands in different positions and temperatures at regular intervals for 15 days. The accuracy standard is –4 to +6 seconds per day. COSC only tests the movement, not the full watch. The case, bracelet, and magnetic resistance all fall outside the test, and for two-hand watches, a seconds hand has to be added to do the necessary tests.

The more stringent METAS method tests the entire finished watch, not just the movement, taking into account how it performs with the case on, in real-world conditions, with exposure to magnetism, temperature changes, and water resistance. To pass, a watch must be accurate to within 0 to +5 seconds per day, and resist magnetic fields up to 15,000 gauss. For Omega’s proprietary certification of Master Chronometer, a watch must pass both COSC and METAS testing.

So, how has Omega managed to award the new Constellation Observatory watches Master Chronometer status even though none in the collection have seconds hands? By devising an accuracy test that doesn’t need the photography or a seconds hand at all.

Courtesy of Omega

Courtesy of Omega

Courtesy of Omega

Courtesy of Omega

Omega’s Laboratoire de Précision has fashioned a self-contained testing unit that continuously captures the sound of each tick and tock while recording environmental parameters (temperature, position, and atmospheric pressure) throughout 25 full days of testing. This is a considerable improvement on photographing the position of the seconds hand, capturing just two data points per day, as this new system generates continuous data from the first second.