The Technical Collections (formerly known as the "Astronomical-Physical Cabinet") house high-quality historical measuring instruments, clocks, and apparatus for physical experiments, especially from the era of the scientific revolution. The nucleus of the collection consists of measuring instruments, planetary clocks, and mechanical celestial globes that Landgrave Wilhelm IV of Hesse-Kassel (1532–1592) acquired for his observatory. Employees of the observatory, such as the clockmaker and mathematician Jost Bürgi and the astronomer Christoph Rothmann, were also among the earliest supporters of the Copernican world view, with Kassel being one of the hotspots of astronomical research in Europe.

After the Thirty Years' War, Landgrave Carl (1654–1730) revived the tradition of Wilhelm IV and significantly expanded the inherited collection in order to equip the Collegium Carolinum, his scientific teaching academy at the Kassel court, with the most precise apparatus for the study of nature. Furthermore, he succeeded in appointing the Huguenot Denis Papin to Kassel, who is considered one of the three pioneers of steam engine construction around 1700. Under Landgrave Friedrich II (1720–1785), the collection of astronomical instruments was mainly expanded when the third Kassel observatory was established on the Zwehrenturm in 1783.

The technical collections experienced their last significant expansion in 1962 through the integration of the historical inventory of angle measuring instruments and precision pendulum clocks, which had been used between 1800 and 1900 on expeditions at the Hamburg Observatory in Bergedorf and for timekeeping at the Port of Hamburg. Today, the Technical Collections of Hessen Kassel Heritage are considered one of the most important special collections of scientific instruments and clocks worldwide.