Observation Texts

Definition

Observation Texts is the broader Late Babylonian / Seleucid-era text-class category, used principally by Neugebauer (and after him by Brown and Steele), that encompasses the Babylonian non-mathematical positional-data corpus — the Astronomical Diaries, Normal Star Almanacs, Goal-Year Texts, Almanacs, Eclipse Records, and Planet Records — taken as a single empirical-data category distinct from the mathematical ACT procedure-texts and ephemerides. The category-name is partly a misnomer: Neugebauer and Sachs showed that many of the dated entries in Seleucid-era "observation texts" (notably solstices, equinoxes, and zodiacal-sign-entry dates of planets) are computed from arithmetical schemes, not observed.

In Tradition

Neugebauer's central finding, established with A. J. Sachs, is that almost all of the Seleucid-period observation-text entries for solstices, equinoxes, and planetary zodiac-ingresses are computed from a simple 19-year-cycle scheme rather than observed. Brown integrates the category into his NMAAT taxonomy: the Observation Texts are the empirical-and-quasi-empirical data substrate from which the ACT mathematical infrastructure was abstracted, with positions of the moon and planets relative to nearby Normal Stars representing the bulk of the actual observational content.

In Practice

For the student of the empirical-vs-computed character of Late Babylonian astronomy, "Observation Texts" is the umbrella name for the corpus that supplies both genuine observations and computed quasi-observations. The most secure observed content is positional: the moon's and planets' offsets from named Normal Stars, recorded in cubits and fingers, are direct measurements. The computed content includes: (1) solstice and equinox dates, which Neugebauer-and-Sachs reconstructed as derived from a Uruk tablet's 19-year-cycle scheme by identifying scheme-dates with civil-calendar dates and dropping fractions; (2) planetary ingresses into zodiacal signs, computed from synodic-period arithmetic; (3) Sirius heliacal-rising dates, computed from period schemes. Treating the Observation Texts as a homogeneous "observation" record was the standard pre-1948 reading, and Schnabel cited it as evidence for precession; the Neugebauer-Sachs finding (1950) replaced that picture. The functional consequence is that the Astronomical Diaries (within Observation Texts) carry the real positional data, while the Almanacs and certain Diary-like entries carry computed-and-rounded calendrical data.

Historical Origin

The category covers texts from approximately 652 BCE (earliest Diary) through the first century CE (latest dated Almanac LBAT 1201, 74/5 CE), with the Seleucid-period subset (~312 BCE - 64 BCE) being the most copiously preserved. Modern critical treatments: Neugebauer, *Astronomy and History: Selected Essays*, essay [16] pp. 250-251 (with Sachs) + essay [34] p. 390; Brown, *Mesopotamian Planetary Astronomy-Astrology* (2000); Hunger & Pingree, *Astral Sciences in Mesopotamia* (1999), Ch. II §B.

Further Reading

• Otto Neugebauer, Astronomy and History: Selected Essays
• David Brown, Mesopotamian Planetary Astronomy-Astrology
• Hermann Hunger & David Pingree, Astral Sciences in Mesopotamia