Hipparchus' Lost Star Catalogue: A Comparative Analysis of Recently Recovered Fragments

Główne pojęcia

This article examines recently discovered fragments of what is believed to be Hipparchus' lost star catalogue, comparing them to his only surviving work, the Commentary on Aratus, to understand their significance and what they reveal about Hipparchus' astronomical methods.

Streszczenie

This article delves into the exciting discovery of fragments from Hipparchus' lost star catalogue. It compares these fragments to Hipparchus' Commentary on Aratus, his only surviving work, to assess their authenticity and understand Hipparchus' approach to astronomy.

The article focuses on four key fragments:

1. Codex Climaci Rescriptus (CCR) and the Northern Crown

• This fragment, the best preserved of the four, describes the Northern Crown constellation, providing its boundaries and the coordinates of its stars.
• The fragment's data aligns with the expected positions of stars in 129 BCE, suggesting its connection to Hipparchus.
• Notably, the fragment uses Hipparchus' unique system of expressing right ascension in terms of "zodiacal signs" along the celestial equator.
• However, some discrepancies exist in how coordinates are expressed compared to the Commentary on Aratus, indicating potential alterations during transmission.

2. Aratus Latinus (AL) and the Great Bear

• This fragment, written in a challenging Latin style, describes the Great Bear constellation.
• Despite its corrupted state, the fragment's data, after careful reconstruction and comparison with the Commentary on Aratus, reveals a close match to star positions in 129 BCE.
• This fragment strengthens the argument for the existence of Hipparchus' lost catalogue and provides further insights into his astronomical practices.

3. P.Aberd. 12, the Small Bear, and the Dragon

• This recently republished papyrus fragment describes the constellations of the Small Bear and the Dragon.
• The fragment's purpose remains debated, with interpretations ranging from a star catalogue to a commentary on Aratus.
• The article analyzes the fragment's content and language, comparing it to the Commentary on Aratus to determine its nature and potential connection to Hipparchus' lost catalogue.

4. Comparing the Fragments and the Commentary on Aratus

• The article compares the data and terminology used in the fragments to Hipparchus' Commentary on Aratus.
• It highlights similarities in star descriptions and coordinate systems, supporting the fragments' Hipparchan origin.
• However, it also acknowledges discrepancies in how coordinates are expressed, suggesting potential changes during the texts' transmission.

The article concludes that while these fragments offer compelling evidence of Hipparchus' lost star catalogue, it's crucial to consider potential alterations during their transmission. Further research and analysis of these fragments promise to deepen our understanding of Hipparchus' work and its impact on the history of astronomy.

Statystyki

The fragment in CCR provides coordinates for stars in the Northern Crown, including β CrB at Scorpion 0.5º (right ascension) or 210º 30¢.
The Exegesis lists β CrB as having a right ascension of 210° 30', matching the CCR fragment.
The AL fragment suggests the Great Bear's W-E extension is from Gemini at an unspecified degree to 185º right ascension.
The AL fragment places the "bright star in the throat" of the Great Bear (likely ο UMa) at Gemini 18º ½ (right ascension) or 78º 30¢.
In 129 BCE, ο UMa had a right ascension of 78º 37¢, closely aligning with the AL fragment.
The AL fragment positions the "last star towards the east" in the Great Bear (likely η UMa) at 30º right ascension, though this is likely a textual error.
Hipparchus' Exegesis places η UMa at Claws 4º (right ascension) or 184º.
In 129 BCE, η UMa had a right ascension of 184º 22¢, matching Hipparchus' data.
The AL fragment places the "star on the shoulders" of the Great Bear (α UMa) at 18º 1/2 from the north pole, implying a declination of +71º 30¢.
In 129 BCE, α UMa had a declination of 71º 28¢, closely matching the AL fragment.
The AL fragment places the "star in the two hind feet" of the Great Bear (likely µ UMa) at 40º from the north pole, implying a declination of +50º.
In 129 BCE, µ UMa had a declination of + 50º 16¢, closely matching the AL fragment.

Cytaty

"The Crown which lies in the northern hemisphere occupies in length 9 degrees and ¼, from the first degree of the Scorpion to 10 degrees ¼ (CCR: 14 and a half) of the same zodiacal sign. In breadth it occupies 6 degrees and ¾, from 49 degrees from the northern pole to 55 degrees and 3/4."
"For in it the star (β CrB) which is toward the west, next to the bright one (α CrB), leads, occupying half of the first degree of the Scorpion."
"The last one, toward the east, is the one which is fourth (ι CrB) (CCR: the one which is) to the east of the bright one (α CrB) […] 49 degrees [from] the northern pole."
"Southernmost is the third [star] (δ CrB), counted from the bright one (α CrB) toward the east, which is 55 degrees and ¾ from the northern pole."

Kluczowe wnioski z

Hipparchus Star Catalogues

by Francesca Sc... o arxiv.org 10-28-2024

https://arxiv.org/pdf/2410.19228.pdf

Głębsze pytania

How might the discovery of further fragments from Hipparchus' star catalogue impact our understanding of ancient Greek astronomy and its influence on later civilizations?

The discovery of further fragments from Hipparchus' star catalogue would be a major event in the history of astronomy. It could significantly impact our understanding of ancient Greek astronomy in several ways:

Precision and Methodology: Analyzing additional fragments could reveal the precision of Hipparchus' measurements and the methods he used. This would allow us to better assess the accuracy of his work and the sophistication of his instruments, potentially uncovering new insights into ancient Greek astronomical practices. For instance, confirming the use of the "zodiacal nomenclature" for right ascension in more fragments would solidify our understanding of this unique system.
Scope and Content: More fragments could shed light on the size and scope of Hipparchus' catalogue. Did it cover the entire celestial sphere or just specific regions? What information did it contain beyond stellar positions and magnitudes? Answers to these questions could significantly alter our perception of the ambition and achievements of Greek astronomy.
Lost Knowledge: Hipparchus' catalogue is often credited as a cornerstone for Ptolemy's Almagest, a foundational text for astronomy for centuries. Uncovering more of Hipparchus' work could reveal lost knowledge that influenced Ptolemy and subsequent astronomers, potentially uncovering previously unknown connections and influences.
Influence on Later Civilizations: A more complete picture of Hipparchus' catalogue could illuminate the transmission of astronomical knowledge from ancient Greece to other civilizations, such as the Islamic world and Renaissance Europe. By comparing Hipparchus' data with that of later astronomers, we could trace the evolution of astronomical thought and identify specific instances of influence.
In essence, further fragments could provide crucial missing pieces in the puzzle of ancient astronomy, allowing us to reconstruct a more complete and nuanced picture of Hipparchus' achievements and their impact on the development of this scientific field.

Could the discrepancies between the fragments and Hipparchus' Commentary on Aratus be explained by a deliberate reinterpretation or adaptation of his original data by later astronomers?

The discrepancies between the fragments and Hipparchus' Commentary on Aratus present an intriguing puzzle. While some differences might be attributed to textual corruption during transmission, as the article suggests, the possibility of deliberate reinterpretation or adaptation by later astronomers cannot be discounted. Here are some possible explanations:

Independent Observations: Some discrepancies, particularly in stellar coordinates, could stem from independent observations made by later astronomers. If they used different instruments or observational techniques, their results might differ slightly from Hipparchus' original data.
Precession of the Equinoxes: Hipparchus is credited with discovering the precession of the equinoxes, a slow shift in the orientation of Earth's axis. Later astronomers, aware of this phenomenon, might have adjusted Hipparchus' coordinates to account for the elapsed time, leading to discrepancies.
Simplification or Clarification: Later astronomers, particularly those with didactic goals, might have simplified or clarified Hipparchus' data for their audiences. This could explain variations in the way coordinates are expressed or the level of detail provided in star descriptions.
Incorporation of New Data: Over time, astronomers continued observing the stars and refining their positions. Later copies of Hipparchus' catalogue might have incorporated these updated measurements, leading to discrepancies with the original data preserved in the Commentary on Aratus.
It is crucial to consider that ancient astronomical texts often went through multiple hands and revisions. Scribes might have introduced errors, and later astronomers might have added their own comments or corrections. Distinguishing between original data and later additions or modifications is a complex task that requires careful analysis and comparison of all available sources.

If Hipparchus was able to compile a star catalogue, what does this suggest about the sophistication of ancient Greek astronomical instruments and observational techniques?

The compilation of a star catalogue, especially one as seemingly accurate as Hipparchus', necessitates a significant level of sophistication in both astronomical instruments and observational techniques. Here's what his achievement suggests:

Precise Instruments: Determining accurate stellar positions requires instruments capable of measuring angles with a high degree of precision. Hipparchus likely used instruments like the armillary sphere, a complex device of nested rings used to determine celestial coordinates, and the dioptra, a sighting instrument with graduated scales for measuring angles. The accuracy of his data suggests these instruments were well-crafted and calibrated.
Systematic Observation: Compiling a star catalogue requires not just individual measurements but a systematic approach to observation. Hipparchus likely developed a consistent methodology for observing and recording stellar positions, ensuring comprehensive coverage of the sky and minimizing errors.
Mathematical Skill: Translating raw observational data into a coherent catalogue requires significant mathematical skill. Hipparchus would have needed a strong grasp of spherical geometry and trigonometry to calculate and represent stellar positions on a celestial sphere.
Timekeeping: Accurate astronomical observations rely on precise timekeeping. Hipparchus likely had access to reliable water clocks or sundials to time his observations and ensure accuracy.
The existence of Hipparchus' star catalogue challenges the notion that ancient Greek astronomy was primarily philosophical or speculative. It demonstrates a high level of practical skill, technological innovation, and mathematical rigor, placing Hipparchus among the pioneers of observational astronomy. His work laid the groundwork for centuries of astronomical progress and highlights the remarkable achievements of ancient Greek science.