This machine, he says, has a circumference of thirty-two feet, being constructed in the form of an armillary sphere.
The horizon diameter of this armillary sphere is about 21 cm.
Never had any armillary sphere so many zones, as there were here circles, which had the light for their centre.
The piece may be referred to as a fine example of the armillary sphere of the period.
At the top, the drip-mould grows into a large trefoil with crockets outside and an armillary sphere within.
On the platform was an armillary sphere designed for observing the heavens.
This globe supports the several circles composing the armillary sphere.
The armillary sphere (Fig. 117) stands at the east end130 of the court.
This is an armillary sphere of brass, the diameter of its largest or zodiacal circle being 14 cm.
The province of the armillary sphere was to make these measurements extremely accurate.
An early astronomical device made of fixed and movable rings representing circles of the celestial sphere, such as the ecliptic and the celestial equator. It was used as early as the third century BCE as both a teaching instrument and an observational tool.