Source citation ledger
Almagest
Claudius Ptolemy
book · c. 150 CE
Ptolemy, Almagest (Mathematical Syntaxis).
Almagest (Mathematical Syntaxis)
Added 2026-10-18 (second new-source wave) for cosmos/instrument leftovers beyond Tetrabiblos and Allen. Keep apart from ptolemy-tetrabiblos.
These are separate Atlas meetings that cite this source. Citation is not proof.
Hellenic religion
Armillary sphere appears in Hellenic religion.
Ptolemy’s Almagest Book V seats the ἀστρολάβον — a nest of graduated rings for ecliptic, equator, and related circles — among the instruments of Hellenistic mathematical astronomy. A named armillary-sphere in that handbook’s ring-instrument neighborhood, not the planispheric astrolabe entity and not a Chinese armillary reception dump.
from Claudius Ptolemy · Almagest, c. 150 CE
appears in · sourced · documented
Mural quadrant appears in Hellenic religion.
Ptolemy’s Almagest Book I seats a meridian plinth and quadrant for measuring noon altitudes of the sun among the opening instrument chapters of the Syntaxis. A named mural-quadrant in that wall/meridian altitude neighborhood under later observatory naming, not the generic later medieval quadrant pad refused here and not a shipboard octant.
from Claudius Ptolemy · Almagest, c. 150 CE
appears in · sourced · documented
Celestial globe appears in Hellenic religion.
Ptolemy’s Almagest Books VII–VIII seat the construction and use of a solid globe marked with the fixed stars and constellation figures among catalog and sphere work. A named celestial-globe in that star-globe neighborhood, not celestial-sphere as the imagined shell alone and not a flat planisphere disc.
from Claudius Ptolemy · Almagest, c. 150 CE
appears in · sourced · documented
Deferent is historically related to Celestial sphere.
Ptolemy’s Almagest planetary books seat the deferent as the large carrying-circle on which an epicycle’s center rides in the geocentric sphere model. A named deferent continuous with that Syntaxis carrying-circle speech, not epicycle as the small loop (no separate epicycle entity here) and not orbit as modern Kepler talk.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Great circle is used in Circle.
Ptolemy’s Almagest Book I seats great circles on the sphere — equator, ecliptic, horizon, meridian — as the largest circles dividing the celestial sphere in spherical astronomy. A named great-circle used as that sphere-circle species, not small-circle as a lesser parallel and not a flat plane-circle dump alone.
from Claudius Ptolemy · Almagest, c. 150 CE
used in · sourced · documented
Small circle is used in Circle.
Ptolemy’s Almagest Book I seats parallels and other lesser circles on the sphere that are not great circles among the apparatus of spherical astronomy. A named small-circle used as that lesser sphere-circle species, not great-circle and not a flat circle dump alone.
from Claudius Ptolemy · Almagest, c. 150 CE
used in · sourced · documented
Equinoctial colure is historically related to Equinox.
Ptolemy’s Almagest seats the colure through the poles and the equinoctial points among the great circles that fix the sphere’s seasonal hinges. A named equinoctial-colure continuous with that equinox-colure speech, not solstitial-colure and not equinox as the day-night hinge alone.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Solstitial colure is historically related to Solstice.
Ptolemy’s Almagest seats the colure through the poles and the solstitial points among the great circles that fix the sun’s standstills on the sphere. A named solstitial-colure continuous with that solstice-colure speech, not equinoctial-colure and not solstice as the day-length hinge alone.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Arctic-circle sky is historically related to Celestial sphere.
Ptolemy’s Almagest Book II seats the arctic circle of always-visible stars for a given latitude among the sphere regimes that bound the inhabited world’s sky. A named arctic-circle-sky continuous with that always-visible polar-circle speech, not antarctic-circle-sky and not arctic as a bare place dump.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Antarctic-circle sky is historically related to Celestial sphere.
Ptolemy’s Almagest Book II seats the opposite always-invisible circle toward the south among the sphere regimes paired with the arctic always-visible bound. A named antarctic-circle-sky continuous with that southern invisible-circle speech, not arctic-circle-sky and not Antarctica as a place dump.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Tropical sky is historically related to Sun.
Ptolemy’s Almagest Book II seats the tropics and the latitudes where the sun can pass through the zenith among the sphere regimes of the inhabited world. A named tropical-sky continuous with that zenith-sun / tropic neighborhood, not tropical-year as the equinox-to-equinox period already met and not a vacation slogan dump.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Precession is historically related to Equinox.
Ptolemy’s Almagest Book VII seats the slow eastward shift of the fixed stars relative to the equinoxes, transmitting Hipparchus’s discovery as a measured motion of the starry sphere. A named precession continuous with that equinox-star shift speech, not north-star as a single id and not a modern earth-axis textbook dump alone.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Zenith appears in Hellenic religion.
Ptolemy’s Almagest seats the zenith as the overhead point for an observer when treating horizon, meridian altitudes, and latitude on the sphere. A named zenith in that Hellenistic mathematical-astronomy speech, not nadir underfoot and not a career-slogan dump.
from Claudius Ptolemy · Almagest, c. 150 CE
appears in · sourced · documented
Nadir appears in Hellenic religion.
Ptolemy’s Almagest seats the nadir as the underfoot opposite of the zenith in the observer’s vertical when the sphere’s poles and horizon are set out. A named nadir in that handbook’s opposite-to-zenith neighborhood, not zenith and not underworld as a place dump.
from Claudius Ptolemy · Almagest, c. 150 CE
appears in · sourced · documented
Azimuth is historically related to Horizon.
Ptolemy’s Almagest treats angles around the horizon and amplitude when rising and setting arcs are computed on the sphere. A named azimuth continuous with that horizon-direction neighborhood under later compass wording, not horizon as the skyline alone and not a navigation-compass instrument dump.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Declination is historically related to Celestial sphere.
Ptolemy’s Almagest seats distances north or south of the equator when converting between ecliptic and equatorial frames and when treating meridian altitudes on the sphere. A named declination continuous with that equator-distance speech under later equatorial-coordinate naming, not terrestrial latitude alone and not right-ascension as the eastward equatorial pad refused here.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Zenith star appears in Hellenic religion.
Ptolemy’s Almagest Book II seats which stars can pass through the local zenith for a given latitude among the sphere regimes of the inhabited world. A named zenith-star in that zenith-transit neighborhood, not zenith as the point alone and not circumpolar as the always-visible class alone.
from Claudius Ptolemy · Almagest, c. 150 CE
appears in · sourced · documented
Transit is historically related to Meridian.
Ptolemy’s Almagest seats stars and the sun crossing the meridian when culmination and meridian altitudes are measured and tabulated. A named transit continuous with that meridian-crossing speech (not Venus-on-sun as the only sense), not conjunction as shared longitude alone and not culmination as the already-walked midheaven pad restated under Tetrabiblos.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Equation of time is historically related to Sun.
Ptolemy’s Almagest Book III seats the solar anomaly and the difference between mean and true solar positions that later equation-of-time speech still gathers when apparent and mean solar time diverge. A named equation-of-time as continuity on that solar-equation path, not bare algebra equation and not analemma as the figure-eight noon path refused here.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Anomalistic month is historically related to Moon.
Ptolemy’s Almagest Book IV seats the moon’s return from perigee to perigee among the lunar periods needed for lunar anomaly and eclipse work. A named anomalistic-month continuous with that perigee-return period, not synodic-month the phases already met and not draconic-month the node return.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Draconic month is historically related to Lunar node.
Ptolemy’s Almagest Book IV seats the moon’s return from node to the same node among the periods that govern eclipse limits and lunar latitude. A named draconic-month continuous with that node-return period, not synodic-month the phases and not a dragon-being dump.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Sidereal day is historically related to Celestial sphere.
Ptolemy’s Almagest seats the daily revolution of the starry sphere against the fixed stars when distinguishing stellar day-motion from solar day-motion. A named sidereal-day continuous with that star-sphere daily return, not synodic-day the sun-noon return and not sidereal-year.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Sidereal year is historically related to Star.
Ptolemy’s Almagest distinguishes the year measured against the fixed stars from the tropical year of the equinoxes when solar and stellar periods are compared. A named sidereal-year continuous with that star-return year, not tropical-year already met and not sidereal-day.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Synodic day is historically related to Sun.
Ptolemy’s Almagest seats the solar day from noon to noon among the time measures that differ from the sidereal day of the starry sphere. A named synodic-day continuous with that sun-noon day neighborhood, not sidereal-day and not synodic-month the lunar phases already met.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Lunar eclipse is historically related to Moon.
Ptolemy’s Almagest Book VI seats lunar eclipse geometry — earth’s shadow, node limits, and durations — as a worked mathematical chapter of the Syntaxis. A named lunar-eclipse continuous with that shadow-on-moon theory, not solar-eclipse and not Tetrabiblos weather-omen eclipse speech.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Solar eclipse is historically related to Sun.
Ptolemy’s Almagest Book VI seats solar eclipse geometry — moon covering the sun’s disk for a place on earth, parallax, and magnitudes of obscuration — among the Syntaxis eclipse chapters. A named solar-eclipse continuous with that covering theory, not lunar-eclipse and not a generic eclipse word alone.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Penumbra is historically related to Eclipse.
Ptolemy’s Almagest Book VI seats the partial shadow fringe around the dark cone when eclipse shadow geometry is set out for sun and moon. A named penumbra continuous with that partial-shadow neighborhood, not umbra the dark core (left to unpublished cosmos-2 claim) and not twilight as sky-light.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Eclipse season is historically related to Lunar node.
Ptolemy’s Almagest Book VI seats the eclipse limits when sun and moon are near a node so that eclipses can occur — the window later eclipse-season speech names. A named eclipse-season continuous with that node-limit neighborhood, not season as a year-quarter and not bare eclipse alone.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Occultation is historically related to Moon.
Ptolemy’s Almagest treats the moon covering a star or planet by passing in front among observations and lunar place-checks that are not sun/moon eclipse cases alone. A named occultation continuous with that covering-by-passage speech, not eclipse as the sun/moon special cases and not conjunction as shared longitude alone.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Annular eclipse is historically related to Sun.
Ptolemy’s Almagest Book VI seats cases where the moon’s apparent disk is too small to cover the sun completely, leaving a bright ring — the geometry later annular-eclipse speech names. A named annular-eclipse continuous with that incomplete-cover solar case, not hybrid-eclipse modern path taxonomy refused here and not solar-eclipse as the total-cover genus alone.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Partial eclipse is historically related to Eclipse.
Ptolemy’s Almagest Book VI seats magnitudes of obscuration when only part of the sun or moon is covered among eclipse computations. A named partial-eclipse continuous with that partial-cover case, not totality and not penumbral-eclipse as the fringe-only lunar case.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Penumbral eclipse is historically related to Moon.
Ptolemy’s Almagest Book VI shadow geometry implies lunar passages that enter only the partial shadow — the case later penumbral-eclipse speech names. A named penumbral-eclipse continuous with that fringe-only lunar case, not penumbra as the fringe alone and not partial-eclipse as a distinct obscuration magnitude pad.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Totality is historically related to Eclipse.
Ptolemy’s Almagest Book VI seats the duration when the sun is fully covered or the moon is fully in the umbra among eclipse timing computations. A named totality continuous with that full-cover interval, not partial-eclipse and not Bailey/diamond-ring contact chrome refused here.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Central eclipse is historically related to Sun.
Ptolemy’s Almagest Book VI seats solar eclipses whose shadow axis meets the earth — the center-line cases later central-eclipse speech gathers for total and annular paths. A named central-eclipse continuous with that axis-on-earth solar geometry, not partial-eclipse off-axis and not hybrid modern path taxonomy refused here.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented
Saros is historically related to Eclipse.
Ptolemy’s Almagest seats long eclipse-return periods in the lunar and eclipse chapters that bring similar sun–moon–node geometry around again — the cycle later called saros in English. A named saros as continuity on that eclipse-period path, not a civil calendar month alone and not eclipse as a single event dump.
from Claudius Ptolemy · Almagest, c. 150 CE
historically related to · sourced · documented