Four different Cosmotrons are shown in the thumbnails below.

Photos 1 and 2: 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

Photos 3 and 4: This black one is pretty funky as well --- maybe copying the Omega Dynamic? This Cal. 7802A based model appeared in 1972.

Photos 5 and 6: 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?

Photos 7 and 8: 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.

Photo 9:Finally, a group shot of Cosmotrons!

Citizen X-8 Cosmotron; All Stainless Steel; 40mm lug-to-lug x 39mm width incl. crown; Cal. 4840; 1967	Citizen Cal. 4840	Citizen Cosmotron; All Stainless Steel; 40mm lug-to-lug x 39mm width incl. crown; Cal. 7802A; 1975	Citizen Cal. 7802A	Citizen Cosmotron; All Stainless Steel; 40mm lug-to-lug x 39mm width incl. crown; Cal. 7803A; 1975	Citizen Cal. 7803A
Citizen Cosmotron; All Stainless Steel with gold bezel; 40mm lug-to-lug x 39mm width incl. crown; Cal. 7804A; 1975	Citizen Cal. 7804A	Group Shot!