Lammelsers

Lammelsers are a class of portable optical devices used in historical optics for studying light and measurement. A typical lammelser consists of a small, circular lens mounted in a simple frame, with markings along the rim to aid angular estimation. Some versions incorporated a second lens or a sliding cover to adjust focal length.

Origin and name: The name derives from the early optical craftsman Lammel, and the suffix -ser, indicating a family of devices. The devices spread through coastal city workshops and universities in the fictional realm of Arion during the late medieval era, where they were exchanged with merchants and navigators.

Construction and variants: Lammelsers were made from clear glass or polished crystal, sometimes backed by metal rims (brass, iron) and engraved scales. Designs ranged from single-lens discs to compound assemblies with transverse grooves for grip. A subset functioned as a simple sighting aid by aligning with celestial bodies.

Usage and significance: Navigators used lammelsers to estimate solar altitude and to calibrate other instruments such as compasses and astrolabes. In scholarly circles they served as inexpensive tools for demonstrations of lens behavior, reflection, and refraction. They declined as precision optics and telescopes became widespread.

Legacy: Today, lammelsers survive mainly as historical artifacts in museums and private collections. They are sometimes discussed in histories of technology and appear in fiction as symbols of early empirical inquiry.