Antikythera mechanism
Gearing
The mechanism is remarkable for the level of miniaturisation and the complexity of its parts, which is comparable to that of fourteenth-century astronomical clocks.

Antikythera mechanism

Section Title: Gearing
Table Section Text: The mechanism is remarkable for the level of miniaturisation and the complexity of its parts, which is comparable to that of fourteenth-century astronomical clocks.

Gear name	Function of the gear/pointer	Expected simulated interval of a full circular revolution	Mechanism formula	Computed interval	Gear direction

x	Year gear	1 tropical year	1 (by definition)	1 year (presumed)	cw

b	the moon's orbit	1 sidereal month (27.321661 days)	Time(b) = Time(x) * (c1 / b2) * (d1 / c2) * (e2 / d2) * (k1 / e5) * (e6 / k2) * (b3 / e1)	27.321 days	cw

r	lunar phase display	1 synodic month (29.530589 days)	Time(r) = 1 / (1 / Time(b2 [mean sun] or sun3 [true sun])) – (1 / Time(b)))	29.530 days

n*	Metonic pointer	Metonic cycle () / 5 spirals around the dial = 1387.94 days	Time(n) = Time(x) * (l1 / b2) * (m1 /l2) * (n1 / m2)	1387.9 days	ccw

o*	Games dial pointer	4 years	Time(o) = Time(n) * (o1 / n2)	4.00 years	cw

q*	Callippic pointer	27758.8 days	Time(q) = Time(n) * (p1 / n3) * (q1 /p2)	27758 days	ccw

e*	lunar orbit precession	8.85 years	Time(e) = Time(x) * (l1 / b2) * (m1 / l2) * (e3 / m3)	8.8826 years	ccw

g*	Saros cycle	Saros time / 4 turns = 1646.33 days	Time(g) = Time(e) * (f1 / e4) * (g1 / f2)	1646.3 days	ccw

i*	Exeligmos pointer	19755.8 days	Time(i) = Time(g) * (h1 / g2) * (i1 / h2)	19756 days	ccw

The following are proposed gearing from the 2012 Freeth and Jones reconstruction:

sun3*	True sun pointer	1 mean year	Time(sun3) = Time(x) * (sun3 / sun1) * (sun2 / sun3)	1 mean year	cw

mer2*	Mercury pointer	115.88 days (synodic period)	Time(mer2) = Time(x) * (mer2 / mer1)	115.89 days	cw

ven2*	Venus pointer	583.93 days (synodic period)	Time(ven2) = Time(x) * (ven1 / sun1)	584.39 days	cw

mars4*	Mars pointer	779.96 days (synodic period)	Time(mars4) = Time(x) * (mars2 / mars1) * (mars4 / mars3)	779.84 days	cw

jup4*	Jupiter pointer	398.88 days (synodic period)	Time(jup4) = Time(x) * (jup2 / jup1) * (jup4 / jup3)	398.88 days	cw

sat4*	Saturn pointer	378.09 days (synodic period)	Time(sat4) = Time(x) * (sat2 / sat1) * (sat4 / sat3)	378.06 days	cw

Sentence(s)

The modelled rotational period of the Saros pointer is 1646.3 days (in four rotations).

final_sentence: The modelled rotational period of the Saros pointer is 1646.3 days (in four rotations).