Astronomical Mapping – an IAU Proposal

For millennia, humans crafted myths from asterisms to track seasons, preserve cultural stories, and mark time, as evidenced by ancient depictions like the Dendera Zodiac (circa 50 BCE) [3]. These celestial maps served critical purposes: seasonal prediction (e.g., Babylonian MUL.APIN for rainy seasons [10]), cultural storytelling (e.g., Greek myths in Ptolemy’s Almagest [12]), and timekeeping (e.g., Indian Nakshatras for rituals [13]). In 1930, Eugène Delporte and the International Astronomical Union (IAU) standardized 88 constellation boundaries using right ascension and declination lines tied to the B1875.0 and B1900.0 epochs, building on the Uranometría Argentina’s framework [1, 2]. However, these rigid boundaries often diverge from historical and cultural understandings. Our investigation, using Carte du Ciel software [4] and historical charts, reveals inconsistencies in the Aquarius-Pisces boundary: the line from Beta to Iota Aquarii crosses into Capricornus, clashing with Aquarius’ traditional water-bearer shape, while stars from Eta Aquarii align with the celestial equator, yet the western boundary dips below it [5]. Pisces incorporates post-telescope stars, highlighting the modern origins of these borders, which evolved significantly in the 17th and 18th centuries [6]. Precession further undermines their relevance in the J2000.0 epoch [7], and stellar proper motion will reshape these boundaries over millennia [18, 19].

These standardized lines exclude non-Western systems, such as the Chinese lunar mansion Xu (β Aquarii) [8], the Indigenous Australian Emu in the Sky, and Polynesian Matariki [9]. Today, the traditional uses of celestial maps—seasonal tracking, storytelling, and timekeeping—are obsolete, supplanted by modern meteorology, atomic clocks, and digital media [14, 15]. As humanity’s perspective shifts beyond Earth, the Earth-centric equatorial coordinate system risks irrelevance, with Delporte’s boundaries potentially losing meaning over time [16, 17]. We propose a dual system: preserving cultural asterisms as a historical archive to maintain their seasonal and cultural significance (e.g., Babylonian Anunitum [10], Polynesian Matariki [11]), while establishing a universe-centric astronomical mapping reference system based on the International Celestial Reference System (ICRS) [20] and Gaia’s 3D stellar data [21, 22]. This approach updates IAU standards for long-term precision and relevance, while safeguarding humanity’s diverse astronomical heritage.

Updated References

  1. Delporte, E. (1930). Délimitation Scientifique des Constellations. Royal Observatory of Belgium.
  2. Paolantonio, S., & García, B. (2019). Uranometría Argentina and the constellation boundaries. Proceedings of the International Astronomical Union, 13(S349), 505-509.
  3. Egypt Museum. (n.d.). The Dendera Zodiac [Bas-relief]. Displayed at the Louvre Museum, Paris, France (E 13420). Retrieved from https://egypt-museum.com/the-dendera-zodiac/
  4. Chevalley, P. (n.d.). Carte du Ciel – SkyChart [Computer software]. Retrieved from https://www.ap-i.net/skychart/en/start
  5. International Astronomical Union. (1930). IAU Constellation Boundaries Map. Adopted at the 3rd General Assembly, Leiden, Netherlands.
  6. Ridpath, I. (n.d.). Constellation boundaries. Retrieved from http://www.ianridpath.com/boundaries.html
  7. Durst, S., Safonova, M., Paolantonio, S., Colazo, M. E., & Li, G. (2020). Galaxy Forum South America-Argentina 2020. Proceedings of the International Astronomical Union, 367, 1-4.
  8. Xiaochun, S., & Kistemaker, J. (1997). The Chinese Sky During the Han: Constellating Stars and Society. Sinica Leidensia, Vol. 38, Brill.
  9. Holbrook, J., Hamacher, D. W., et al. (2015-2018). Contributions on cultural astronomy. IAU General Assembly Proceedings, Honolulu (2015) and Vienna (2018). Retrieved from http://cdsarc.u-strasbg.fr/viz-bin/Cat?VI/49
  10. Hunger, H., & Steele, J. (2019). The Babylonian Astronomical Compendium MUL.APIN. Routledge.
  11. Te Ara – The Encyclopedia of New Zealand. (n.d.). Matariki – Māori New Year. Retrieved from https://teara.govt.nz/en/matariki-maori-new-year
  12. Ridpath, I. (n.d.). Ptolemy’s Almagest. Retrieved from http://www.ianridpath.com/startales/almagest.html
  13. Harness, D. (2020). The Nakshatras of Vedic Astrology: Ancient & Contemporary Usage. Retrieved from https://dennisharness.com/articles/the-nakshatras-of-vedic-astrology-ancient-contemporary-usage/
  14. Aveni, A. (2001). Empires of Time: Calendars, Clocks, and Cultures. University Press of Colorado.
  15. Stern, D. P. (2004). The History of Timekeeping. Retrieved from http://www-istp.gsfc.nasa.gov/stargaze/Stimkeep.htm
  16. Cloudy Nights. (2017). Constellation Boundaries and Precession. Retrieved from https://www.cloudynights.com/topic/580180-constellation-boundaries-and-precession/
  17. Kaler, J. B. (2012). The Ever-Changing Sky: A Guide to the Celestial Sphere. Cambridge University Press.
  18. Binney, J., & Tremaine, S. (2008). Galactic Dynamics. Princeton University Press.
  19. KQED. (2012). Do Constellations Change Over Time? Retrieved from https://www.kqed.org/quest/41313/do-constellations-change-over-time
  20. USNO. (n.d.). International Celestial Reference System (ICRS). Retrieved from https://aa.usno.navy.mil/faq/ICRS_doc
  21. ESA. (2018). Gaia Creates Richest Star Map of Our Galaxy and Beyond. Retrieved from https://www.esa.int/Science_Exploration/Space_Science/Gaia/Gaia_creates_richest_star_map_of_our_Galaxy_and_beyond
  22. Gaia Collaboration, et al. (2018). Gaia Data Release 2: Summary of the contents and survey properties. Astronomy & Astrophysics, 616, A1.

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