It is an extremely fine, rare and unusual astronomic, self-winding, 18K yellow gold wristwatch with mean time indication, nocturnal sky chart of the Northern Hemisphere, moon phases and moon orbit, time of the meridian passage
of Sirius and moon.
During their stay at Het Behouden Huys, Barents's crew took nine altitudes of the sun at meridian passage and two for stars, in order to find the latitude.
Sights of the sun and stars were taken at meridian passage with a marine astrolabe (Stimson, 1988) or with a cross-staff (Morzer Bruyns, 1994), and occasionally with an astronomical ring.
Latitude was obtained from the altitude at upper (south) meridian passage by the formula:
to find the declinations at local meridian passage on the corrected journal dates (see Table 1).
For the sight reduction of this observation, the precise date is not important: the sun was near its solstice, and the computer-calculated declination at meridian passage is 23[degrees]29' for 23 June or 23[degrees]27' for 25 June.