A chronometer watch is a watch tested and certified to meet certain precision standards. In Switzerland, only timepieces certified by the COSC may use the word 'Chronometer' on them. However, numerous prominent Swiss watch manufacturers do not submit their movements for COSC certification, although such movements would probably easily qualify as chronometers under the COSC certification rules.
The term chronometer is also used to describe a marine chronometer used for celestial navigation. The marine chronometer was invented by John Harrison in 1730. This was the first iteration of a series of chronometers which enabled accurate marine navigation. For the next 250 years, an accurate chronometer was essential to any kind of marine or air navigation until the implementation of global satellite navigation at the end of the 20th century. The marine chronometer is no longer used for navigation.
... that merkhets were Ancient Egyptian timekeeping devices that tracked the movement of certain stars over the meridian in order to ascertain the time during the night, when sundials could not function?
The Wikipedia 1.0 Editorial team identified the following articles relating to Time as Vital: "for which Wikipedia should have a corresponding high-quality article, and ideally a featured article." Those marked with this icon: are also considered to be Core articles, "one of the core set of articles every encyclopedia should have."
Their quality-scale rating as of February 2008 is listed alongside each:
Spread the word by posting this portal link in the See Also sections of time-themed articles, using this code:
Note that the Time templates (posted in Topics on each page of this Portal) all contain a link back to the Portal, so if an article has one of those templates, it doesn't technically need another link.