Editing Solstice (section)

===Ancient Greek names and concepts===
The concept of the solstices was embedded in ancient Greek [[celestial navigation]]. As soon as they discovered that the Earth was spherical<ref>{{cite book
|author=Strabo
|author-link=Strabo
|title=The Geography
|at=II.5.1
|quote=sphairikē ... tēs gēs epiphaneia, spherical is the surface of the Earth}}</ref> they devised the concept of the [[celestial sphere]],<ref>{{cite book
|author=Strabo
|author-link=Strabo
|title=The Geography
|pages=II.5.2
|quote=sphairoeidēs ... ouranos, spherical in appearance ... is heaven}}</ref> an imaginary spherical surface rotating with the heavenly bodies (''ouranioi'') fixed in it (the modern one does not rotate, but the stars in it do). As long as no assumptions are made concerning the distances of those bodies from Earth or from each other, the sphere can be accepted as real and is in fact still in use. The Ancient Greeks use the term'' "ηλιοστάσιο" (heliostāsio)'', meaning ''stand of the Sun''.

The [[star]]s move across the inner surface of the celestial [[sphere]] along the [[circumference]]s of [[circle]]s in [[Parallel (geometry)|parallel]] planes<ref>Strabo II.5.2., "aplaneis asteres kata parallēlōn pherontai kuklōn", "the fixed stars are borne in parallel circles"</ref> [[perpendicular]] to the Earth's axis extended indefinitely into the heavens and intersecting the celestial sphere in a celestial pole.<ref>Strabo II.5.2, "ho di'autēs (gē) aksōn kai tou ouranou mesou tetagmenos", "the axis through it (the Earth) extending through the middle of the sky"</ref> The Sun and the [[planet]]s do not move in these parallel paths but along another circle, the ecliptic, whose plane is at an angle, the [[obliquity of the ecliptic]], to the axis, bringing the Sun and planets across the paths of and in among the stars.*

[[Cleomedes]] states:<ref>{{cite book
|title=Cleomedes' Lectures on Astronomy: A Translation of The Heavens
|author=Cleomedes
|author-link=Cleomedes
|others=Translated by Alan C. Bowen and Robert B. Todd
|publisher=[[University of California Press]]
|location=Berkeley
|date=2004
|isbn=0-520-23325-5
|page=41}} This translation cites this passage at the end of Book I Chapter 2 but other arrangements have it at the start of Chapter 3. In the Greek version of {{cite book|title=Cleomedis De motu circulari corporum caelestium libri duo|url=https://archive.org/details/kleomedouskyklik00cleo|author=Cleomedes |editor-first=Hermann|editor-last=Ziegler |publisher=B. G. Teubneri|date=1891|pages=[https://archive.org/details/kleomedouskyklik00cleo/page/32 32]}} the passage starts Chapter 4.</ref><blockquote>The band of the [[Zodiac]] (''zōdiakos kuklos'', "zodiacal circle") is at an oblique angle (''loksos'') because it is positioned between the tropical circles and equinoctial circle touching each of the tropical circles at one point ... This Zodiac has a determinable width (set at 8° today) ... that is why it is described by three circles: the central one is called "heliacal" (''hēliakos'', "of the sun").</blockquote>

The term heliacal circle is used for the ecliptic, which is in the center of the zodiacal circle, conceived as a band including the noted constellations named on mythical themes. Other authors use Zodiac to mean ecliptic, which first appears in a gloss of unknown author in a passage of Cleomedes where he is explaining that the [[Moon]] is in the zodiacal circle as well and periodically crosses the path of the Sun. As some of these crossings represent [[eclipse]]s of the Moon, the path of the Sun is given a synonym, the ''ekleiptikos (kuklos)'' from ''ekleipsis'', "eclipse".