- Museum number
- 1909,0617.1
- Description
-
This brass instrument is the earliest dated European astrolabe.
The MATER which is cut from a solid block is graduated clockwise 0° to 360°. The inside is empty. The THRONE is crescent shaped and the shackle saddle shaped.
On the RETE, with a distinctive Y inside the ecliptic, 33 stars are indicated as follows: 'Mirac', 'batnachaythos', 'Menkar', 'Augetenar', 'Aldeboran', 'alhayok', 'Rigil', 'elgeuze', 'alhabor', 'algomeyza', 'Markeb', 'alfard', 'Cor leon', 'edub', 'algorab', 'alchimek', 'benetnac', 'alramek', 'elfeca', 'Yed', 'alacrab', 'alhae', 'Taben', 'Wega', 'altair', 'delfin', 'aldigege', 'Cor corvi', 'aldera', 'Musida equi', 'Cenok', 'Hum{erus} equi', 'Skeder'. Ten of the star-pointers are zoomorphic (birds and the head of a dog), two are heads of human beings. The circumferential frame has a dragon's head and tail respectively at the ends. The ecliptic bears the usual Latin names of the zodiacal signs, each sign being divided to 30°. On the reverse the markings for the ecliptic are laid out and partially numbered; some of the star pointers are sketched in.
All five PLATES bear markings for the circles of the tropics and the equator. One of the plates is otherwise left empty. Plates 1a, 1b, 2a, 2b, 3a, 3b and 4a and 4b have markings for the almucantars every 5° (every 3° on 3a and b), markings for the unequal hours numbered 1 to 12, and the very unusual marking for the prime vertical (except on 4b), without markings for the astrological houses. They are laid out and labelled for the following latitudes ('Latitudo'): 1a) 32° 0' 'Jerlm' (Jerusalem); 1b) 35° 30', 'Babilonie'; 2a) 41° 50', 'Rome'; 2b) 44° 40', 'Motis pessulani' [Montpellier]; 3a) 48° 32', 'parisius'; 3b) 51°50', 'Oxonie' [Oxford]; 4a) 66° 0', 'Tab{u}la sub polo zodiaci'; 4b) 'Tabula sub Equinoctiali'.
The BACK bears four altitude scales starting at the top and running clockwise 90° to 0°, 0° to 90° twice, divided to single degrees. The single degree scale is also used for the circular solar scale, anticlockwise starting at the right, marked with the usual Latin names of the signs of the zodiac, each sign divided to 30°. Further to the inside is an eccentric calendrical scale, marked with the Latin names of the months (with the slightly unusual forms 'Marcius' and 'Mayus') anticlockwise starting at the first point of Aries. The equinoxes correspond to March 13 and September 16. Inside this scale is a band with the names of 46 saints (amongst them on 19th May Dunstan, 26th May Augustine of Canterbury, 17th June Botulph) and Christian feasts linked to given dates and Dominical letters. The lower half of the vacant space is taken up by a pair of SHADOW SCALES to the base of 12. Above the diameter between the shadow scales and the calendrical scales is the date.
The ALIDADE is counter-changed and has two sighting vanes, the pin is very simple, the wedge is unusually long with a small horse head at one end.
- Production date
- 1326
- Dimensions
-
Diameter: 132 millimetres
-
Thickness: 10 millimetres (mater)
- $Inscriptions
-
- Curator's comments
- It is very likely that this astrolabe ... is of English origin: three of the saints mentioned in the list on the back are of particular English significance, the rete has the typical Y-shape and zoomorphic star pointers as described by Chaucer and one of the plates is marked for Oxford.
The plates have the very unusual marking for the prime vertical, but are not laid out for the astrological houses.
[S. Ackermann, EPACT 1998, http://www.mhs.ox.ac.uk/epact/catalogue.php?ENumber=40428]
- Location
- On display (G40/dc10/sB)
- Exhibition history
-
Exhibited:
2021 20 May- 22 Aug, London, BM, Room 35 – Thomas Becket: Murder and the Making of a Saint
1987-1988 6 Nov-6 Mar, London, Royal Academy of Arts, Age of Chivalry: Art in Plantagenet England 1200-1400
- Acquisition date
- 1909
- Department
- Britain, Europe and Prehistory
- Registration number
- 1909,0617.1