The iconic picture of Clyde on his way in — I guess — to a night of observing.  Nevermind that it’s broad daylight.  The plates for the 13-inch astrograph were so big (14 by 17 inches) that V.M. Slipher had to design a special holder to give the glass plates a slight curvature — so light would strike the edges of the plates correctly.  You screwed down the four corners of the plate with thumbscrews (visible in this picture, in fact).  And if you got the plate in too tight — pow — it would explode like a bomb.