Geological Chronicle
Balmer is the basalt-covered remains of a lunar impact feature east-southeast of the crater Vendelinus. Only the heavily worn southern and eastern sections of the outer wall still survive, with the remainder overlaid by a basalt flow that joins the nearby mare.
The structure forms part of the larger Balmer-Kapteyn Basin. Its surviving rims are from the pre-Nectarian period of the lunar geologic timescale, and light plains deposits overlay the mare basalt, as evidenced by multiple dark-halo craters.
Balmer was considered a Constellation program region of interest. David W. G. Arthur and Ewen Whitaker introduced the name into lunar nomenclature in the Rectified Lunar Atlas in 1963, honoring Swiss mathematician and physician Johann J. Balmer, and the International Astronomical Union adopted it in 1964.