Aug. 20, 1949: Las Cruces, New Mexico (BBU)
10:45 p.m. Astronomer and discoverer of planet Pluto, Clyde W. Tombaugh, with wife and mother-in-law, all saw a rigid formation of faint bluish-green rectangles as if windows on a solid dark object about 1° across, which flew at high speed from zenith SSE to about 35° above the horizon where it disappeared all the while the rectangles foreshortening due to the slant angle. No sound. Wife thought she saw faint interconnecting glow. (FUFOR Index; etc.) 3 secs. [Tombaugh did not run to the papers with this story, nor formally report it to AMC. But he talked with his friends and colleagues who worked out of White Sands. Many of them had already seen unusual objects in the sky. Tombaugh himself had seen two other “unknowns” and three green fireballs. He felt that these objects “defied any explanation of known phenomena, such as Venus, atmospheric optics, meteors, or planes.”- UFOs & Government]

Mike Swords:
I don't think that Tombaugh was much interested in BlueBook {Grudge at the time} and so didn't report. A year or more later he talked a fellow launch observer to let him send that fellow's report in, but I don't think he ever sent his own. Tombaugh's letter from NICAPs files should be in there {I think that it is in my article, but I'm attaching a separate frame of it}; and there is a CSI-NY statement about his wife's version of the sighting {her sketch differs a bit from Clyde's, as she saw a curved line of windows and he a curve --- if one wishes to interpret it that way --- plus a few others forming what could be drawn as an ellipse or a hexagon or octagon of lights. I've attached three small resource pix of that; and there's Menzel's pictorial representation of what he thought Tombaugh told him; and last and definitely least, an old sketch that I made trying to illustrate the case. (Tombaugh 1-5 below)