By 1909, Lowell and William H. Pickering had suggested several possible celestial coordinates for such a planet.
By 1909, Lowell and William H. Pickering had suggested many possible places in the Solar System where the planet could be.
By 1909, Lowell and William H. Pickering had suggested many possible places in the Solar System where the planet could be.
Change to simpler wording: By 1909, Lowell and William H. Pickering had suggested several possible celestial coordinates for such a planet. Output: