@rob#1
Of course Skylab 2 Doctor/physician Joseph Kerwin wore a Speedmaster chronograph
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https://airandspace.si.edu/collection-objects/chronograph-kerwin-skylab-2
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The little box at the wristband has an image of Snoopy (dressed as a pilot wearing a cape) on it and was a
passive radiation dosimeter used during the 28 days long SL2 mission aboard Skylab space station...
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The other photos showing astronauts wearing a pair of wrist watches has been a usual technique since White's EVA in June 1965.
Both White & McDivitt wore a pair of Speedmaster chronographs because on the one hand, NASA only had 4 Omega Speedmaster and wanted to fly all four and on the other hand, one chronograph was used on Houston mission time, while the second could be used to time other events.
Aboard the Space Shuttle, most astronauts were allowed to wear a personal watch, IMHO the best example was Doctor/physician Norman Thagard wearing a Speedmaster & an Accutron Astronaut exactly as Gordon Cooper aboard Mercury "Faith 7" did in May 1963...
Recent photos of astronauts aboard the ISS show them wearing an ActiWatch which monitors exposure to light, sleep etc...
Go through this complete thread as most things have been explained already
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