Pappus
of Alexandria Parsons,
William Payne-Gaposchkin,
Cecilia Helena Penrose,
Roger Penston,
Michael Penzias,
Arno Allan Piazzi,
Giuseppe Pickering,
Edward Charles Plaskett,
John Stanley Pliny
the Elder, (Gaius Plinius Secundus) Pond,
John Pons,
Jean-Louis Ptolemy,
(Claudius Ptolemaeus)