Gyldén is the remnant of a lunar crater that is located to the northeast of the walled plain Ptolemaeus. It lies along the prime meridian of the selenographic coordinate system, and less than 150 km south of the lunar equator. Nearby craters of note include Herschel to the west, the flooded Réaumur to the north, and Hipparchus to the east. The heart-shaped rim of this crater is in poor condition, having been eroded by impacts until the disintegrating remnants form an uneven ring of peaks and valleys around the interior floor. (wikipedia entry)
