Armillary sphere

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Armillary sphere was an instrument used in Indian astronomy. [1]

Lalla wrote of it's importance, pointing out that the mean motion of planets was easily visible on it. [2]

Template:Ref-par

[[Template:Ref-par]] wrote on the Armillary sphere his [[Template:Ref-GolaD]]. He described in great detail it's general arrangement. He started with the viṣuvad circles (3 main great circles), namely the [1]

English Sanskrit description references
Solstiital Colure Dakṣiṇottara a north-south circle [1]
Equinoctial celestial equator Ghaṭikāmaṇḍala perpendicular to Dakṣiṇottara [1]
Equinoctial colure - perpendicular to Ghaṭikāmaṇḍala and Dakṣiṇottara [1]

He mentioned svastika - 4 crosses made by the equinoctial colure with the other viṣuvads, at the 'cardinal points'.[1]

Next he described the Apama-vṛtta (ecliptic), ahorātra-vṛtta (diurnal circles), orbits of the planets, the pāta (lunar nodes), and finally the Nakṣatragola / Bhagola (Starry sphere), the Khagola (Celestial sphere, outside of the starry sphere), the clay Earth, another circle (Unmaṇḍala) to hold it all, and spacers (śara-daṇḍikā).[1]

Lalla

Lalla, in Template:Ref-SiDhVr, describes an armillary with 51 great cirlces representing the objects of the heavens. [3]

Lalla's armillary sphere[3]
madhyajyāvṛtta meridian
madhyalagna merdiain ecliptic point
ḍṛṇmaṇḍala above the madhyalagna, where planet is seen
dṛggatijivāvalaya ahead of the madhyalagna

Each of the 7 planets gets a set of the following:[3]

Each of the 5 star-planets gets:

The Bhagola, sphere of stars, is inside the Khagola, or celestial sphere. The latter can be mounted on four pillars, while the Bhagola can be rotated by ropes, etc. [4]

For more detail, please see the article on Lalla.

Sūrya Siddhānta

Armillary sphere described in Sūrya Siddhānta[5]
Bhūbhagola Stellar sphere
kakṣa hoops to sustain the Earth model
bhagaṇa degrees of the circle
aṅgula divisions of bhagaṇa
vikṣepa latitude
bha asterisms
ayana solstices
viṣuvat equinoxes, also listed as equator
krānti "circle of declination" (runs through both solstices, planets turn on it)
apamaṇḍala ecliptic
lagna orient ecliptic point - at orient horizon
astamgacchat occident ecliptic point
madhyama meridian ecliptic-point
kṣitija horizon
antyā jyā between kṣitija and madhya
caradala sun's ascensional difference
interval between viṣuvat & kṣitija

Also mentioned:

  • The Seven Sages (saptarṣayas) of Agastya, Brahmā, etc.
  • Waterflow
  • quicksilver

Automatic armillary spheres

The Sūrya Siddhānta describes an automatically moving armillary sphere, involving quicksilver (mercury), water, and oil. It declines to give a description. Āryabhaṭa, Lalla, and others give similar and (usually vague) descriptions of automatic armillary sphere devices. [6]

These may be amongst the earliest analog computers, comparable with the Antikythera Mechanism, Zhang Heng and his water-powered armillary sphere, Al-Jazari and astronomical clocks, etc. Please see the article on mercury (metal) for more information. Template:Fact

See also

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Template:Refia8.2.1
  2. Template:Refia8.1.1
  3. 3.0 3.1 3.2 Template:Refia8.6.1
  4. Template:Refia8.6.2
  5. Template:Refia8.6.3
  6. See Template:Refia section on armillary spheres.