Complex sentence: The comet was last seen between September 27 and November 26,1913, first by Pablo T. Delavan (La Plata Astronomical Observatory) and then others, it was predicted to return 1976 but was never observed, and is now considered lost.
Split into simpler sentences: The comet was last seen between September 27 and November 26,1913, first by Pablo T. Delavan (La Plata Astronomical Observatory) and then others. It was predicted to return in 1976 but was never observed, and is now considered lost.