Friday, November 08, 2013

Hoptroff No 10

A couple of months ago I wrote about this pocket watch that is as accurate as an atomic clock (it is self powered). Here is the article:

Hoptroff No 10

Well with the ongoing SalonQP in London, the first live pictures of the pocket watch has appeared. It looks awesome.

Photographs: Hoptroff

How to use the pocket watch? Your guess is as good as mine. There is a user guide on the their website. Functionality? Well, from Hoptroff's website:


The current 12-hour time (local and UTC selectable), as measured by the atomic clock.

Hour, 1 – 12
Minute, 0 – 59
Seconds (atomic), 0 – 59


Sidereal time measures the rotation of the earth relative to the stars, rather than the sun. Although it uses a “24-hour” clock dial, each sidereal “day” is actually 23 hours, 56 minutes 4 seconds long. This is why the seconds hands (3) and (6) are not in sync. Stars rise and set at the sidereal time every day.

Sidereal hours, 0 – 23 (retrograde), as measured by atomic clock
Sidereal minutes, 0 – 59 (retrograde)
Sidereal seconds, 0 – 59 (pendulum)

LONGITUDO (Longitude)

Longitude measures the angular position east or west of Greenwich, UK. This value is set with a sextant using the noon sight method, in order to compare local noon with a chronometer reference time, just as Harrison did, except with an atomic clock and without the need to refer to admiralty tables.

Longitude – coarse degrees, 180°E – 180°W
Longitude – fine degrees, 0° – 180° (retrograde)
Longitude – minutes, 0’ – 59’ (retrograde)

VIS RELIQA (Power Remaining)

Battery power remaining, 100% – 0%

ERROR HORÆ (Time Error)

From moment the time is set, timekeeping slowly drifts. (In the case of atomic timekeeping, extremely slowly.) The Time Error is a measure of the maximum degree to which timekeeping could have drifted.

Time error, 10-9s – 10s (logarithmic)

ÆTAS LUNÆ (Moon Age)

The traditional moon age indication, in days since the new moon.

Moon age in days, 0 – 29½ (retrograde)

MERIDIES LUNÆ (Lunar Transit)

The local time when the moon will be highest in the sky. Moonrise will be six hours before lunar transit, moonset will be six hours after.
Transit time, 00:00 – 23:50 (retrograde)


The local tide height. Tidal harmonics vary throughout the globe, based on the relative positions of the sun and moon, and the local geography. First modelled by Sir William Thomson in 1860, these eight tidal harmonics are stored for three thousand ports worldwide. The closes port is selected for the indication. It is the most complex complication in the timepiece.

Tide height, -½m – 15m

UMOR (Humidity)

Relative humidity, 0% – 100%, as measured by on-board instrument, with 24-hour historic animation

TEMPERIES (Temperature)

Temperature, -40°C – 50°C, as measured by on-board instrument, with 24-hour historic animation. (Note: Usage below -35°C is not recommended due to battery chemistry.)

PRESSUS (Pressure)

Atmospheric pressure, 955mbar – 1045mbar, as measured by on-board instrument, with 24-hour historic animation

ANNUS (Annual wheel)

The annual wheel smoothly completes a rotation once per year.

Month, Jan – Dec. Common constellation of solar transit, ^ – i (Aries – Pisces)

LATITUDO (Latitude)

Latitude is the angular position north or south of the equator. After a noon sight is taken, the noon sun height is entered on this dial, and then the actual latitude is determined relative to the declination of the sun.
Latitude – minutes, 0’ – 59’ (retrograde)
Latitude – degrees, 90°S – 90°N

DIES (Date)

Day of the month in the local time zone, 1 – 31 (perpetual).

AXIS SEPT (Due North)

Due north, as measured by on-board instrument, with 24-hour historic animation. Selectable correction for magnetic deviation from true north

The pocket watch will be available in 2014. 

For more information:


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