Moon apparent geocentric equatorial coordinates#75
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The algorithm described by Jean Meeus in Astronomical Algorithms produces apparent ecliptic coordinates that can be converted into apparent geocentric equatorial coordinates. _Geocentric_ is important here because it came to my attention recently that it is possible to have topocentric equatorial coordinates, which can then be directly converted into topocentric horizontal coordinates. This change is a first step into having all these coordinates available for the Moon: - apparent ecliptic coordinates - apparent geocentric equatorial coordinates - apparent topocentric equatorial coordinates - topocentric horizontal coordinates More work will be done later to the coordinates object so that these conversion are easier to use and more general to implement for all astronomical bodies. Results have been compared with the IMCCE and show an accuracy of 1 arcsecond (of degrees or hours). ```rb moon = Astronoby::Moon.new(time: Time.utc(2003, 9, 1)) coordinates = moon.apparent_geocentric_equatorial_coordinates coordinates.right_ascension.str(:hms) # => "14h 12m 12.2352s" coordinates.declination.str(:dms) # => "-11° 35′ 7.9466″" ```
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## 0.5.0 - 2024-06-11 _If you are upgrading: please see [UPGRADING.md]._ [UPGRADING.md]: https://github.com/rhannequin/astronoby/blob/main/UPGRADING.md ### Features * Make `Sun#mean_anomaly` public ([#72]) * Moon ecliptic coordinates ([#73]) * Moon apparent geocentric equatorial coordinates ([#75]) * Moon horizontal coordinates ([#76]) * Assume Moon's equatorial coordinates are geocentric ([#77]) * Use observer object for geocentric parallax ([#79]) * Moon's phase angle and illuminated fraction ([#80]) * Monthly Moon phases ([#82]) * Rationalize negative degree angles ([#83]) * Factorize Moon phases periodic terms ([#85]) * Introduce observation events for Moon ([#86]) [#72]: #72 [#73]: #73 [#75]: #75 [#76]: #76 [#77]: #77 [#79]: #79 [#80]: #80 [#82]: #82 [#83]: #83 [#85]: #85 [#86]: #86 ### Improvements * Create FUNDING.yml ([#70]) * Bump standard from 1.35.1 to 1.36.0 ([#71]) * Bump rexml from 3.2.6 to 3.2.8 ([#74]) * Expand the number of tested Ruby versions ([#84]) * Add Ruby 3.1.6 and 3.3.2 coverage ([#88]) * Improve and update documentation ([#87]) * Update UPGRADING.md ([#89]) [#70]: #70 [#71]: #71 [#74]: #74 [#84]: #84 [#88]: #88 [#87]: #87 [#89]: #89 ### Backward-incompatible changes * Use Observer in Horizontal coordinates ([#69]) * Introduce `Astronoby::Distance` value object ([#78]) [#69]: #69 [#78]: #78 **Full Changelog**: v0.4.0...v0.5.0
rhannequin
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### Features * Make `Sun#mean_anomaly` public ([#72]) * Moon ecliptic coordinates ([#73]) * Moon apparent geocentric equatorial coordinates ([#75]) * Moon horizontal coordinates ([#76]) * Assume Moon's equatorial coordinates are geocentric ([#77]) * Use observer object for geocentric parallax ([#79]) * Moon's phase angle and illuminated fraction ([#80]) * Monthly Moon phases ([#82]) * Rationalize negative degree angles ([#83]) * Factorize Moon phases periodic terms ([#85]) * Introduce observation events for Moon ([#86]) [#72]: #72 [#73]: #73 [#75]: #75 [#76]: #76 [#77]: #77 [#79]: #79 [#80]: #80 [#82]: #82 [#83]: #83 [#85]: #85 [#86]: #86 ### Improvements * Create FUNDING.yml ([#70]) * Bump standard from 1.35.1 to 1.36.0 ([#71]) * Bump rexml from 3.2.6 to 3.2.8 ([#74]) * Expand the number of tested Ruby versions ([#84]) * Add Ruby 3.1.6 and 3.3.2 coverage ([#88]) * Improve and update documentation ([#87]) * Update UPGRADING.md ([#89]) [#70]: #70 [#71]: #71 [#74]: #74 [#84]: #84 [#88]: #88 [#87]: #87 [#89]: #89 ### Backward-incompatible changes * Use Observer in Horizontal coordinates ([#69]) * Introduce `Astronoby::Distance` value object ([#78]) [#69]: #69 [#78]: #78 **Full Changelog**: v0.4.0...v0.5.0
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The algorithm described by Jean Meeus in Astronomical Algorithms produces apparent ecliptic coordinates that can be converted into apparent geocentric equatorial coordinates.
Geocentric is important here because it came to my attention recently that it is possible to have topocentric equatorial coordinates, which can then be directly converted into topocentric horizontal coordinates.
This change is a first step into having all these coordinates available for the Moon:
More work will be done later to the coordinates object so that these conversion are easier to use and more general to implement for all astronomical bodies.
Results have been compared with the IMCCE and show an accuracy of 1 arcsecond (of degrees or hours).