- Museum number
This brass ASTROLABE is one of four instruments by the famous Nuremberg maker Georg Hartmann (1489-1564) in the British Museum.
The MATER is graduated 90°to 0°, 0° to 90°, 90° to 0°, 0°to 90° clockwise. The rim is riveted to the back plate. The inside of the mater is marked with circles for the tropics and the equator and the east-west and meridian lines.
The THRONE, which is riveted to the rim, has the characteristic Hartmann shape: two roses, a rosette, and two fir cones in a triangular layout supported by foliate scrolls.
The RETE is in the usual Hartmann shape which consists mainly of arcs of circles and split ends of the circle for the tropic of Capricorn. It has 27 pierced star pointers, some of which are bent or broken. The following stars are named: 'CAVDA CETI', 'VMB ANDRO', 'VENTER CETI', 'GORGON', 'NARES CETI', 'CAPRA', 'OCVLVS TAVRI', 'PES SIN ORONIS', 'CANIS', 'PROCION', 'HIDRA', 'REGVLVS', 'CRATER', 'CAVDA LEON', 'CORVVS', 'SPICA [Virgo]', 'CAV VRSE', 'ARCTVRVS', 'CORONA', 'MAN SERP', 'CAP SERP', 'LIRA', 'AQVILA', 'DELPHIN', 'HOLOR', 'HVME EQVI', 'CRVS PEGASI'.
The ECLIPTIC is marked with the usual Latin names of the zodiacal signs and is divided into 12 x 30°. The equinoctial bar is counterchanged six times on both sides of the ecliptic, between the ecliptic and the tropic of Capricorn and between the ecliptic and the central disc. The reverse of the rete is punched with an 'F' at the intersection of the tropic of Capricorn and the solstitial bar. This letter is also to be found punched on the three plates and scratched on the reverse of the alidade and on the bottom edge of the mater.
The three PLATES are marked on both sides with circles for the tropics and the equator, and almucantars for every three degrees. The azimuths are labelled for every ten degrees. They further bear markings for the unequal hour curves, numbered in Roman numerals clockwise I to XII (additive form for 4, i.e., IIII), and the astrological houses in the manner of Regiomontanus, numbered in Arabic numerals 1 to 12 anticlockwise. The plates are laid out and marked for the following latitudes ('LATI'): 1a) XXXIX; 1b) XLII; 2a) XLV; 2b) XLVIII; 3a) LI; 3b) LIIII. The latitude is repeated in Arabic numerals on the small tongues which locate the plates in the mater. All three plates are marked with an 'F' on one side and next to it scratched an italic 'f'.
The BACK has the following concentric circular scales (from the outside): 1) an altitude scale 90° to 0°, 0° to 90°, 90° to 0°, 0° to 90°; 2) a regular division of the zodiacal signs into 12 x 30° (in Roman numerals), running anticlockwise, starting with Aries at the equinoctial line; 3) a circle with the usual Latin names of the corresponding zodiacal signs together with their symbols. Further inside are 4) a calendar scale divided to the number of days for each month, corresponding to 5) the innermost circle, marked with the usual Latin names of the months. The equinoxes are at March 11 and September 13½.
The upper part of the space inside these circles is taken up by a double HORARY QUADRANT with the curved lines for hours numbered 1 to 12. In the lower half are two shadow scales to the base 12, each marked 'VMBRA RECTA' and 'VMBRA VERSA' and numbered by 3. Inside the shadow scales are the maker's signature and the place and date of production.
The counterchanged ALIDADE bears ornamented pointers. One of the two folding sighting vanes is missing, the other one is ornamented with a scalloped edge. The pin, washer and wedge are all replacements.
The numerals and letters are punched and tend not to be aligned with each other.
- Production date
Diameter: 140 millimetres
Thickness: 7 millimetres
- Curator's comments
The labelling of the different components with the same letter or number ('F' in this case) suggests that Hartmann had quite an extensive astrolabe production. Another Hartmann astrolabe dated 1532 is in the Adler Planetarium, Chicago, and yet another was in The Time Museum, Rockford, Illinois (now dissolved).
For details of other Hartmann astrolabes see the following:
Anthony Turner, 'The Time Museum, Volume 1, Part 1: Astrolabes', Rockford: The Time Museum (1985), pp128-131
Roderick and Marjorie Webster, 'Western Astrolabes', Historic Scientific Instruments of the Adler Planetarium & Astronomy Museum (Volume 1), Chicago: Adler Planetarium (1998) pp53-55
Koenraad van Cleempoel, ' Astrolabes at Greenwich', Oxford: Oxford University Press and the National Maritime Museum (2005) pp143-146
- Not on display
- Exhibition history
1974 29 Apr-30 Jun, Bath, Holburne of Menstrie Museum, A Girdle Round the Earth
- Latest: 2 (Mar 2017)
- Acquisition date
- Britain, Europe and Prehistory
- Registration number