PT Journal AU Fomin, J TI Rudolfine Sundial with Planetary hours and Gregorian Calendar : Erasmus Habermel's Unknown Device SO Staleta Praha PY 2022 BP 66 EP 76 VL 38 IS 2 DI 10.56112/sp.2022.2.03 WP https://staletapraha.cz/en/artkey/pha-202202-0003.php DE Prague - Erasmus Habermel - sundials - mechanical devises - astronomy - astrology - Gregorian calendar - Rudolph II. SN 02316056 AB This article presents a portable horizontal sundial made by Rudolfine maker of mathematical and astronomical instruments Erasmus Habermel († 1606). This hitherto unpublished artefact from the collections of the National Heritage Institute is currently stored in the depository of the Rajec nad Svitavou castle. Detailed description of the sundial and its functions is provided together with comparison with other devices by the same maker. The article also presents new findings regarding the life of Erasmus Habermel, based on the manuscripts of the Prague City Archives. ER