ECLIPTICAL Coordinates by Ai

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When did astronomers swap out the old Ecliptic Coordinates System for the new Equatorial Coordinates System? Did the 17th century scientist Christiaan Huygens make use of astronomy's Equatorial Coordinates System?

Copilot 🌌 Great questions—let’s dive into the celestial coordinate shake-up and Huygens’ role in it.
📐 Transition from Ecliptic to Equatorial Coordinates
Astronomers didn’t exactly “swap out” the ecliptic coordinate system for the equatorial one in a single moment. Instead, it was a gradual evolution:
- Ancient Astronomy: The ecliptic coordinate system was dominant in ancient times, especially for tracking the Sun, Moon, and planets. It’s based on the plane of Earth’s orbit around the Sun and was central to Babylonian, Greek, and medieval Islamic astronomy.
- Renaissance to Early Modern Era: As observational tools improved and the heliocentric model gained traction, astronomers began favoring the equatorial coordinate system, which is based on Earth’s rotation and the celestial equator. It’s more stable for star mapping because stars don’t move along the ecliptic like planets do.
- 17th Century Shift: By the 17th century, the equatorial system was becoming more widely used, especially with the rise of telescopic astronomy and celestial cartography. It offered better precision for fixed stars and was more compatible with mechanical clocks and sidereal time.
mechanical clocks too mechanical clocks too So, it wasn’t a hard swap—it was more like the equatorial system gradually became the standard for stellar observations, while the ecliptic system remained useful for planetary motion.
🔭 Did Christiaan Huygens Use the Equatorial System?
Christiaan Huygens (1629–1695) was deeply involved in astronomy—he discovered Saturn’s moon Titan, studied Saturn’s rings, and invented the pendulum clock to improve timekeeping for astronomical observations.
While there’s no direct evidence that Huygens explicitly used the equatorial coordinate system in the modern sense, it’s highly likely he was familiar with it:
- He worked during the time when the equatorial system was gaining traction among European astronomers. - His pendulum clock was designed to keep sidereal time, which is directly tied to the equatorial system’s concept of right ascension. - His contemporaries, like Johannes Hevelius and Giovanni Cassini, were already using equatorial coordinates for star catalogs and telescopic observations.
So while Huygens may not have formalized or published work using equatorial coordinates explicitly, he was certainly operating within the framework that supported and benefited from it. If you’re curious, I can show how these coordinate systems differ visually or even walk you through how to convert between them. Want to explore that next?

OUT TAKES FAVES
"It’s more stable for star mapping because stars don’t move along the ecliptic like planets do."
Ssssoooo The 'cachet' of the ecliptic, which had formerly been understood to be 'the special path the Sun and planets take going around Earth' lost some of its lustre importance and prerogative when Copernicus informed everyone those cosmic bodies indeed aren't really going around Earth.
Besides which, and perhaps more importantly for practical astronomers, the Equatorial Coordinates System is appreciably more stable for purposes of surveying stars because stars don’t appear to move along the ecliptic like planets appear to do."
Equatorial still fave system today for a substantial portion of astronomical research. So out with the old & in with the new. Totally different planes of reference. But both astronomy methods operate by and through tenets of the age-old base-60 number system that originated as if out of the blue in prehistoric /and illiterate (no clay tablets yet) / Sumeria and Elam. Sexagesimal number values and the accompanying celestial network of gracefully curved lines compose the vital nutrients, tendons and sinews of b Both systems. From them mankind learned so much. A marine chronometer is a precision timepiece that is carried on a ship and employed in the determination of the ship's position by celestial wiki https://www.worldhistory.org/image/17185/harrisons-h5-marine-chronometer/

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The ancient records of astronomical observations kept on clay tablets, known as the Babylonian Astronomical Diaries, give distances between the ecliptic and celestial objects, and between any two celestial objects (stars, planets, moon) in terms of "fingers" apart or "cubits apart". For example see this page from ORACC https://oracc.museum.upenn.edu/adsd/X103321 The Babylonian Astronomical Diaries indeed contain detailed recordings of celestial observations, including measurements of angular distances between objects in terms of units like "fingers" or "cubits." These units are part of their sexagesimal (base-60) system and reflect their methods of measuring angles and distances in the sky.

Understanding the Units:
Fingers: A "finger" (or digit) was a small unit of angular measurement, roughly corresponding to a fraction of a degree. Given that the Babylonians used a sexagesimal system and their units often related to parts of a degree, a finger might be roughly equivalent to about 1/12 of a degree (since the ancient sexagesimal system often divided degrees into 60 parts).
Cubits: A "cubit" was a longer unit of measurement, traditionally based on the length of a forearm, but in astronomical contexts, it might be used as a larger angular measure or as a linear measure when describing distances on a celestial sphere. The precise interpretation depends on context, but it's often a larger measure than a finger. Interpreting the Measurements: When the records specify that two objects are "X fingers apart," they are indicating an angular separation. For example, "5 fingers" might correspond to about 5/12 degrees, or approximately 0.4167 degrees. Similarly, "cubits apart" could be a larger angular or linear measure, depending on the context, possibly used when describing the relative positions of objects or their distances along a certain reference frame.

Reconstructing the Measurements:
Using the known units: 1 finger ≈ 1/12 degree ≈ 0.0833 degrees 1 cubit (if used as an angular measurement) might be larger, perhaps around 1 degree or more, but conventions vary. Significance:

These measurements indicate that the Babylonians had a sophisticated system for recording and perhaps estimating angular distances in the sky, which contributed to their advanced astronomical calculations.