Another detail was that it had a small toothed "stop" at the upper pivot to set the angle of the derailleur as it hung from the dropout. I've used the Athena, not with Campy's Synchro indexing shift levers, but rather with their excellent "retrofriction" levers (another nice bit of componentry that didn't survive the indexing era).
With those smooth-acting levers, I've found that the Athena is a really nice shifting little derailleur.
The Chorus derailleur shifted more precisely and was a lot quieter than past Campy derailleurs." They went on to say, "If you want indexed shifting on your all-Campy bike, Chorus plus Synchro is the best combination." As glowing as that review was, I don't believe that opinion was shared by all.
The 2-position parallelogram was a really interesting idea -- but it never caught on. In early 1988, Campagnolo released Croce d'Aune, named after the famous mountain pass where the young Tullio Campagnolo, his fingers frozen numb in the cold, was inspired to create the first quick release hub. Like the C-Record and almost all other Campy derailleurs dating back to the original Gran Sport, it utilized the traditional hanging parallelogram structure.
Unlike any other, it used a combination of cable actuation and an unusual articulating tie-rod to keep it tracking the cogs closely with a narrower chain gap. According to Chuck Schmidt, of Velo-Retro, the top of the tie-rod was held by the derailleur fixing bolt with a ball joint, and the bottom of the rod moved with the derailleur body.
Pulling the lever to shift, the cable pulled the body back, while the tie rod pushed the derailleur body inwards, driving it from one cog to the next.
Whereas Shimano and Sun Tour designed full systems of interrelated parts -- shift levers, derailleurs, freewheels/cassettes, chains, and even cables (necessitating a complete drivetrain component upgrade, or better yet, just a whole new bike) -- Campagnolo, on the other hand, tried to make Syncro work with their existing derailleurs. The standard parallelogram with a single spring-loaded pivot (which essentially dated back to about 1950) did not track the cogs as closely as the dropped/slanted parallelogram architecture, had a wide "chain gap" on the smaller cogs, and required a fair amount of the overshift/back-off technique to make the shift.
In addition, there were two versions released of their Syncro indexing shift levers, plus Centaur and Euclid mountain-bike groups.
Sometimes these mutations turn out to be beneficial and live on, perhaps to even become a new species eventually.
Consider the first fish that had the ability to breathe air on land, eventually leading to amphibians.
Although an improvement, the C-Record's basic parallelogram structure was on the verge of extinction.
In 1987-88, Campagnolo released Chorus -- the first of their derailleurs to make a complete break with the traditional Campy design.