You have a very nice chronograph. It's definitely worth a trip to a watchmaker for repairs.
Underneath that scratched crystal you'll likely find a dial that looks like this:
(
thanks @MSNWatch )
Omega and Tissot were sister companies, together with Lemania, in the holding company
Société Suisse pour l’Industrie Horlogère (SSIH).
Co-branded Omega/Tissot dials were sold in the Brazilian market from 1935 until the 1950s, when the brands reverted to their respective identities.
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