Four different Cosmotrons are shown below.

1. The Citizen X-8 Cosmotron was the first Japanese electronic watch; it appeared in 1967. The movement in the X-8 is quite different from the other 3 Cosmotrons shown here, but is the same as the movement used in the Caravelle Transitorised watches

2. The mineral crystal on this green watch is so facetted it makes photography difficult. I'm not brave enough to wear this watch in public --- it is so 1970's and the gold bezel just makes things even worse! This Cal. 7804A based model appeared in 1972.

3. This black one is pretty funky as well --- maybe copying the Omega Dynamic? This Cal. 7802A based model appeared in 1972.

4. All the Cosmotrons are fairly scarce but this third one is very unusual. It has a button at the 8 oclock position; when pressed, it zeros the constant second hand --- maybe a doctor's watch for taking a pulse?