Astronomer-scientist (1907-2004) associated with the Franklin Institute, known for his pioneering work on the Martian clock and calendar. Vintage glossy 8 x 10 photo of Levitt holding a scale model, signed and inscribed in fountain pen, "To The Ken Browne's, with very best wishes, I. M. Levitt.” Reverse bears a typed collector's notation indicating that it was received in 1959. In fine condition, with a light paperclip impression to the top edge.