22. Astronomer’s rings by Gualterus Arsenius, Louvain, 1567

Type: instrument
Inv. No. 48126
Source: MHS

Gemma Frisius designed this instrument and published an account of its use in 1534. This example was made in his Louvain workshop by his ‘nephew’, Gualterus Arsenius, who does not mention his own name when he signs the instrument, but only that of his famous mentor: ‘Nepos Gemmæ Frisij Louanij fecit 1567.’ It is essentially a portable equatorial instrument and could readily be used as a universal equinoctial sundial. Gemma’s account also includes applications to surveying.

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