MOM Budapest Compensating Polar Planimeter, Original Sliding Wooden Case, c. 1940s–1950s

A precision mechanical calculator from mid-20th century Hungary: a compensating polar planimeter by MOM Budapest (Magyar Optikai Művek, the Hungarian Optical Works), used by surveyors and cartographers to measure the exact area of irregular shapes on maps simply by tracing their outline.

- Stamped with the MOM Budapest mark and serial number on the metal arm
- Complete set: tracing arm, pole arm with round counterweight, and the separate metal calibration bar with '0' and '2' screw holes — the parts most often missing from surviving examples
- Housed in its original wooden sliding case with fitted velvet lining

Fully disassembled and nested into its case, this instrument is often mistaken at first glance for an odd caliper or a broken scale part — in fact it is a precise mechanical computer for area measurement, and a favourite piece of steampunk-style industrial desktop display for collectors of scientific and surveying instruments.

Weight approx. 691 g per set. Case dimensions approx. 27 x 10 x 6 cm.