Brief description P140 continues to set new standards in precision timing, in terms of both the quality and quantity of pulsars timed at the sub-microsecond level. Recent highlights include highest precision timing (74 ns), the best relative timing (pulsar versus pulsar) of 200 ns, new parallaxes, DM variations and outstanding astrometry.
P140 has been conducted for more than ten years. We propose to continue this experiment, improving timing methodologies and precision. This unprecedented precision timing baseline provides exciting opportunities to investigate the existence and level of any Gravitational Wave Background and allows pulsar astrometric parameter estimations with unprecedented accuracies in astronomy.