Punched Cards as Position Indicators for Spectrographic Plates
Rapid location of the significant regions on spectrographic plates by use of templates or position indicators can speed up plate measurements considerably. Punch cards for computer use provide a basic grid of 960 positions over a 7.0-in. ×2.9-in. area, and in several designs the 12 rows and 80 columns are legibly numbered. Holes in a punch card serve not only to indicate position, but can also be used as windows for photometric measurements if the card is used as a mask directly on the uncoated side of the plate.
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