Qing · Astronomer

Cassini 噶西尼

Gaxini

Attested AD 1625 - AD 1723

Passages: 12
Chapters: 2
Histories: 1

Overview

Cassini was an Astronomer.

Life and dates

Attested activity

AD 1672 康熙十一年
Directly stated · Draft History of Qing 50, passage 27
AD 1625 to AD 1712 近世刻白爾、噶西尼等
Dated from the passage context · Draft History of Qing 26, passage 44
AD 1723 雍正癸卯
Dated from the passage context · Draft History of Qing 50, passages 3, 12

Key source chapters

Draft History of Qing, Chapter 50 Volume 50 Treatises 25: Calendar 6 11 passages
Draft History of Qing, Chapter 26 Volume 26 Treatises 1: Astronomy 1, Celestial Phenomena, Earth Shape, and Terrestrial Distances 1 passage

Origins and identity

Western 西人
Directly stated · Draft History of Qing 26, passage 44; Draft History of Qing 50, passage 12

Career and standing

astronomer 西人
Directly stated · Draft History of Qing 50, passages 12, 19

Places and affiliations

At France 富郎濟亞國 · Relation Observed at
Directly stated · Draft History of Qing 50, passage 27
At latitude 44° north 北極出地高四十四度處 · Relation Observed at
Directly stated · Draft History of Qing 50, passage 22

Learning and skills

Skill astronomical measurement 測驗 · Level renowned
Directly stated · Draft History of Qing 50, passages 19, 27

Events and relationships

Derived mars and solar parallax
Scientific · Investigator · With Richer (利實爾)
Directly stated · Draft History of Qing 50, passages 28-30
Derived refraction formula
Scientific · Investigator
Directly stated · Draft History of Qing 50, passages 19-23
Established angle area methods
Scientific · Investigator
Directly stated · Draft History of Qing 50, passage 38
Measured annual perigee motion
Scientific · Observer
Directly stated · Draft History of Qing 50, passage 42
Measured lunar inequalities
Scientific · Observer
Directly stated · Draft History of Qing 50, passages 89, 96, 103, 107
Measured mars zenith distance
Scientific · Observer · With Richer (利實爾) · At France 富郎濟亞國
Directly stated · Draft History of Qing 50, passage 27

Show 5 more source-backed claims

Measured node angle limits
Scientific · Investigator · With Newton (奈端)
Directly stated · Draft History of Qing 50, passage 121
Measured obliquity
Scientific · Observer · With Riccioli (利酌理)
Directly stated · Draft History of Qing 50, passage 12
Supplied solstice constants
AD 1723 雍正癸卯 · Scientific · Authority
Directly stated · Draft History of Qing 50, passage 45
Took deferent as ellipse
Scholarly · Theorist · Mode named-source-report Source Work Daily Solar Motion Treatise (Later Compilation) 考成後編日躔歷理
Directly stated · Draft History of Qing 26, passage 44
Relation Collaborated with · Person Richer (利實爾)
Directly stated · Draft History of Qing 50, passage 27

References in the histories

Search passages

History

12 passages

Draft History of Qing, Chapter 26Volume 26 Treatises 1: Astronomy 1, Celestial Phenomena, Earth Shape, and Terrestrial Distances · 1 passage

考成後編日躔歷理云：「西法自多祿某以至第谷，立為本天高卑、本輪、均輪諸說，近世刻白爾、噶西尼等，又以本天為橢圓。」 The Daily Solar Motion Treatise notes: "From Ptolemy through Tycho came deferents, epicycles, and eccentrics; Kepler and Cassini made the deferent elliptical."

Draft History of Qing, Chapter 50Volume 50 Treatises 25: Calendar 6 · 11 passages

黃赤大距，古闊而今狹，恆有減而無增，西人利酌理、噶西尼測定黃赤大距二十三度二十九分，比第谷所定少二分三十秒，比刻白爾所定少一分。 The obliquity of the ecliptic was greater in antiquity and has steadily narrowed; Riccioli and Cassini measured it at 23°29′ — 2′30″ below Tycho and 1′ below Kepler.

噶西尼反覆精求，謂視線光線所歧雖有不同，相合則有定處。 Cassini, after painstaking inquiry, showed that however much the sight line and light ray diverge, their point of convergence is fixed.

康熙十一年壬子秒分前十四日夜半，火星與太陽沖，西人噶西尼於富郎濟亞國測得火星距天頂五十九度四十分一十五秒，利實爾於同一子午線之噶耶那島測得火星距天頂一十五度四十七分五秒，同時用有千里鏡能測秒微之儀器，與子午線上最近一恆星，測其相距。 On the night fourteen days before the Kangxi 11 renzi epoch mark, at Mars's opposition, Cassini in France measured Mars at 59°40′15″ from the zenith while Richer on Cayenne, on the same meridian, found 15°47′5″; both used telescopic instruments precise to the second and measured each planet's distance from the nearest meridian star.

噶西尼所得火星較低一十五秒，因恆星無地半徑差以之立法，用平三角形，推得火星在地平上最大地半徑差二十五秒，小餘三七。 Cassini's Mars appeared 15″ lower; since fixed stars show no parallax, they used plane triangles to derive Mars's maximum horizon parallax as 25.37″.

噶西尼等乃立角積相求諸法，驗諸實測，斯為菂合。 Cassini and his colleagues devised methods relating angle and area that matched observation exactly.

西人噶西尼等測得每歲平行一分二秒五十九微五十一纖零八忽，比甲子元法多一秒四十九微有奇。 Cassini measured the annual advance of perigee at 1′2″59.51‴08, slightly more than 1″49‴ above the jiazi epoch system.

用西人噶西尼所定，推得雍正癸卯年天正冬至為丙申日丑正三刻十一分有奇，比甲子元法遲二刻。 From Cassini's constants, the winter solstice of Yongzheng guimao falls on day bingshen at the third quarter of the chou watch — about two quarters later than the jiazi epoch system.

西人噶西尼以來，屢加測驗，定日在最高朔望前後四十五度，最大差為三十三分一十四秒； Cassini's observations fix the maximum second inequality at 33′14″ when the Sun is at apogee and 45° from syzygy;

西人噶西尼以來，取月距日與月高距日高共為九十度時測之，除末均之差外，其差與月距日或月高距日高之獨為九十度者等。 Cassini found that when the sum of the Moon's elongation and the separation of their apogees equals 90°, the correction—aside from the final inequality—equals that when either alone is 90°.

西人噶西尼以來，測日月最高同度或日月同度兩者只有一相距之差，則止有三均。 Cassini found that when the solar and lunar apogees coincide, or when the Sun and Moon share the same longitude with only one separation variable, three inequalities suffice.

西人奈端、噶西尼以來，測得日在兩交時，交角最大為五度一十七分二十秒； Newton and Cassini measured the maximum node angle at 5°17′20″ when the Sun is at the nodes;