During the post-World War Two period, there were a great many chronographs imported into the US under just about as many trade names. Astin may have been a private label for a jewelry store, or it just may have been a name chosen for it's generic quality.
These watches are typically fitted with good quality movements by Landeron, Venus or Valjoux, and function just as you describe. If the movement is a particularly rare or desirable variation, then these watches might attract some collector interest, but in general, they are valued for the function and styling. The weak point has proven to be the cases, as the solid gold cases are generally notoriously thin, and the plated cases rarely have held up well. If yours has a good case, then count that as a bonus.
I personally consider these to be some of the bast values available in vintage wristwatches, considering the cost of "brand name" chronos, many of which use the same movements.
My two cents,