Maritiem Digitaal
collectie zoeksyteem van de maritieme musea
Celestial clockwork globe
| titel | Celestial clockwork globe
|
|---|
| inventarisnummer | GLB0136
|
|---|
| collectie | Globes
|
|---|
| museum | National Maritime Museum, Greenwich
 |
|---|
| datum | 1728
|
|---|
| omschrijving | Celestial clockwork globe. Astronomical details on the sphere show that only the most important stars are indicated. There is no magnitude table but the stars are represented by three different symbols. The Milky Way is drawn (dotted) but not labelled. The Magellanic Clouds are labelled. A total of eleven stars and four star groups are named. The 48 Ptolemaic constellations and four of the non-Ptolemaic constellations are drawn. There are also six of the southern constellations and those of Plancius. The style of the constellations follows Hercules with a club and apples; the Twins have an arrow, a knife, and the traces of a musical instrument.
The clockwork mechanism allows the globe to revolve at sidereal time about its polar axis, driven from within by a pendulum-controlled movement mounted on this axis. The main driving mechanism consists of a brass, four-pillar 'going-barrel' movement. Although in practical terms the accuracy of the conversion from solar to sidereal time in this gearing is perfectly adequate, it is not particularly accurate given the contemporary options available. For full details about the cartography and construction of this clockwork globe please refer to the related publication.
|
|---|
| afmetingen | Overall: 438 x 219 mm; Sphere diameter: 150 mm
|
|---|
Commentaar van bezoekers