Comparison of plates used for the APOGEE-N instrument (left) and the APOGEE-S instrument (right). Both plates are the same physical size, but, due to the differing telescope f/ ratios have different plate scales. APOGEE-S plates are machine-marked when APOGEE-N plates are marked by hand. APOGEE-S plates have two obscured regions that are used to place cameras, whereas the obscured regions in the APOGEE-N plate do not require physical hole (a central post is mounted in the center of the plate).
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