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statementVerified

Planisphaerium presents stereographic projection as a public instrument-text

Planisphaerium presents stereographic projection of the celestial sphere. Ptolemy’s documented role is: He wrote on stereographic projection, a basis for the later astrolabe. In the causal graph this event strengthens Digital Learning Access, a driver that weakens Learning Poverty Rate (low- and middle-income countries) — an improving welfare path.

Read the full account

Planisphaerium presents stereographic projection of the celestial sphere. Ptolemy’s documented role is: He wrote on stereographic projection, a basis for the later astrolabe. Later Latin from Arabic is the public carrier; he did not typeset it. A projection treatise is not a gazetteer’s error-heading. Later editors, printers, and excavators remain named where they appear. Ptolemy's documented role is: He wrote on stereographic projection, a basis for the later astrolabe.

Context

A mathematical instrument tradition, unnamed copyists, and later astrolabe-makers already sit in the file. A projection is not unique authorship of every later brass astrolabe. Later Latin is access. Named others on the file: Unnamed copyists, later astrolabe-makers, and Arabic-Latin translators share the treatise’s survival. The public setting is the file around 0150-08-01. Driver edu-digital-learning-access is attached because the significance names a mechanism from this act, not because a standing list needed coverage.

Why it matters

Complex later carrier. Welfare reading improving. Lag to any modern indicator is not treated as zero. This path is attached because the mechanism is named from this act, not because a driver list needed coverage. The welfare reading on this path is improving.

If a number is not in the two records named above, it is not supplied here.

Who was responsible

Contribution type and responsibility level for each recorded actor — not sole-author shorthand.

  • Ptolemy

    Person

    Direct responsibility

    responsibility level 0.4 · verified

    He wrote on stereographic projection, a basis for the later astrolabe. Later Latin from Arabic is the public carrier; he did not typeset it.

What changed

Fact → Driver → Indicator. Relationship strength orders the paths; it is not the observed indicator movement.

Evidence

The sources behind this fact and its verification state.

Verified2 sources on file
  1. 1.Britannica — astrolabe, Ptolemaic projection heritageEncyclopaedia Britannica · High credibility · verified
  2. 2.Britannica — Ptolemy, Planetary HypothesesEncyclopaedia Britannica · High credibility · verified
What the sources establish

Britannica independently identifies Planisphaerium as a distinct Ptolemaic projection text. Official: Britannica — Ptolemy, Planisphaerium (https://www.britannica.com/biography/Ptolemy (opens in a new tab); Encyclopaedia Britannica). Independent: Britannica — astrolabe, Ptolemaic projection heritage (https://www.britannica.com/science/astrolabe-instrument (opens in a new tab); Encyclopaedia Britannica). The two URLs are different pages. Where the carrier is a later edition or a received narrative, that limit is stated rather than upgraded to an autograph. Official carrier: Britannica — Ptolemy, Planisphaerium (https://www.britannica.com/biography/Ptolemy (opens in a new tab); Encyclopaedia Britannica). Independent carrier: Britannica — astrolabe, Ptolemaic projection heritage (https://www.britannica.com/science/astrolabe-instrument (opens in a new tab); Encyclopaedia Britannica).

Established: Planisphaerium as a Ptolemaic work. Not established: that Geography is this same book.

Confidence is stated on the impact path, not hidden in adjectives.

Later competitions, monuments, translations, UNESCO listings, museums, and adaptations are not converted into extra lifetime acts.

That reading is an impact-path choice, not a property stored on the Fact itself.

Naming Ptolemy does not delete co-authors, institutions, or later transmitters. The lag from 0150-08-01 to any measured indicator is not treated as zero. Alternative explanations — weather, other armies, later statutes, or independent cultural change — remain live where the sources do not close them.

Causal path

How this event connects to drivers and indicators in the graph.

  1. ActorPtolemy
  2. contributed toFactPlanisphaerium presents stereographic projection as a public instrument-text
  3. strengthensDriverDigital Learning Access
  4. weakensIndicatorLearning Poverty Rate (low- and middle-income countries)

Cite this page

Factrail. (2026). Planisphaerium presents stereographic projection as a public instrument-text. Factrail. https://factrail.ai/facts/pto-planisphaerium

https://factrail.ai/facts/pto-planisphaerium

Accessed 16 October 2026.

By the Factrail desk · Method: how we source and score · Last reviewed

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