Mathematical Jewel Astrolabe by Charles Whitwell
Record status
Individual type · partial
Period
1595
This 388 mm diameter brass astrolabe is a construction based on the 'Mathematical Jewel' design published by John Blagrave in 1585. Signed by Charles Whitwell and dated 1595, the instrument utilizes a universal projection of the saphea type.
The mater contains lines for right ascension and declination, an ecliptic line, and hour lines numbered 1 to 12. Its rete design is divided into two distinct halves: one side features a skeletal grid of meridians and parallels combined with a southern ecliptic arc, while the other side displays star pointers and the northern ecliptic. The limb includes a zodiacal calendar with English month names and degree scales. The instrument was formerly in the collection of Sir Robert Dudley, who bequeathed it to the Grand Duke of Tuscany.
It is currently held by the Istituto e Museo di Storia della Scienza in Florence.
Evidence at a glance
- Linked sources
- 1
- Photograph views
- 1
- Catalogue references
- 0
Counts describe this entry’s documentation, not authenticity, rarity or completeness. Photographs may show one specimen; check each caption and licence.
Technical characteristics
- Date
- 1595
- Type
- English astrolabe
- Maker
- Charles Whitwell
- Origin
- English
- Material
- Brass
- Provenance
- Sir Robert Dudley
- Design source
- John Blagrave
- Place recorded
- England
- Maker / attribution
- Charles Whitwell
Design
- Visible features
- • The limb features a zodiacal calendar with English month names • The rete is split between a stereographic grid and traditional star pointers • The suspension assembly includes a throne, shackle, and ring • The instrument is signed on the verso as 'Charolus Whitwell fecit 1595'
- Rete Configuration
- The rete is characterized by a distinctive split design. One half contains a skeletal grid of meridians and parallels based on the universal projection, accompanied by an arc representing the southern half of the ecliptic. This section includes a zodiacal scale and a meridian bar marked with degrees. The opposing half of the rete contains pointers for named stars and the corresponding northern half of the ecliptic. A diametric bar connects the two halves, featuring a degree scale radiating from the center. The edge of the rete also includes a degree scale, which is numbered specifically on the side containing the grid.
- Construction and Design
- The astrolabe is constructed from brass and measures 388 mm in diameter. It is designed according to the 'Mathematical Jewel' principles described by John Blagrave in 1585, utilizing a universal projection of the saphea type within the mater. The limb is secured by a series of screws and features a suspension system consisting of a throne, shackle, and ring. The limb incorporates a zodiacal calendar with an outer scale of dates, with months named in English. The degree scales on the limb are divided to 10, 5, and 1 units, allowing for precise measurement. Inside the mater are lines for every degree of right ascension and declination, with hour lines numbered 1 to 12 and 12 to 1.
- Signature and Provenance
- The instrument is signed 'Charolus Whitwell fecit 1595' on the verso, which remains incomplete. The verso also contains an altitude scale along the edge. The engraving style is associated with the navigation function of the device, intended for locating stars and reference points when specific latitude coordinates are not known. The provenance of the astrolabe is linked to Sir Robert Dudley, who transported a group of objects from England. These items were subsequently bequeathed to the Grand Duke of Tuscany. The instrument is now housed in the collection of the Istituto e Museo di Storia della Scienza in Florence.
Identification
- Inventory Number
- 1095
- Source note
- Facts transcribed from the linked source listing or collection record. Attribution and specifications are source-reported and have not been independently authenticated.
Catalogue references
No catalogue numbers recorded. Numbers are only published once transcribed from a verified edition of a standard catalogue — they are never inferred.
Research required
- Research required: The verso of the instrument is described as incomplete
- Research required: The intended primary function for navigation is inferred from the type of engraving