Equinoctial Sundial by Dion Geerts

Equinoctial Sundial by Dion Geerts

<< >>
Usage conditions apply
Downloads
Description
This brass universal equinoctial ring dial consists of a meridian ring, hour ring, rotating crosspiece or bridge, and sliding suspension ring/handle. One side of the meridian ring contains a nautical quadrant calibrated for solar altitude from 0 to 80 by single degree. The hour ring is calibrated on one side from I to XII x 2 by I. The hour ring is also calibrated along its inside edge from 1 to 12 x 2 by 1. The bridge has a pinhole gnomon sliding over a calendar scale calibrated and lettered by month and by zodiacal sign on verso. A previous cataloguer commented that: "Cursor track not long enough to allow cursor to reach winter solstice mark. Capricorn and Cancer apparently drawn outside annual path of sun. First point of Aries taken as midpoint of scale." Both sides of the meridian ring and one side of the hour ring are engraved with a list of 40 European cities and latitudes from Copenhagen to Malta and Dublin to Moscow. There is some artistic engraving on the gnomon and bridge.
Location
Currently not on view
Object Name
sundial, equinoctial
maker
Geerts, Dion
Measurements
overall:.5 cm x 7.1 cm x 8.5 cm; 3/16 in x 2 25/32 in x 3 11/32 in
ID Number
MA.336092
catalog number
336092
accession number
316529
subject
Mathematics
Timekeeping
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Data Source
National Museum of American History
Nominate this object for photography.   

Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.

If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.

Comments

Add a comment about this object