Reedy Creek Observatory

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Reedy Creek Observatory
Asperia Street in Reedy Creek, Queensland.jpg
Observatory code 428   OOjs UI icon edit-ltr-progressive.svg
Location Reedy Creek, City of Gold Coast, Queensland, AUS
Coordinates 28°06′S153°24′E / 28.1°S 153.4°E / -28.1; 153.4
Australia relief map.jpg
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Location of Reedy Creek Observatory
Reedy Creek Observatory
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Reedy Creek Observatory (observatory code: 428) is an amateur astronomical observatory and is the location for observations of near-Earth objects by John Broughton, an Australian astronomer. As of 22 October 2025, Reedy Creek Observatory was ranked 36th in the world by the Minor Planet Center on its list of "most prolific discovery sites," with 1,237 discoveries between 1997, the year of its first light, and 2008. [1]

Contents

The observatory is located in Reedy Creek, a suburb of Gold Coast, Queensland, at 66 metres (217 ft) above sea level. [2]

Telescopes and instruments

The observatory uses a 0.51m f/2.7 Newtonian with an Apogee AP6Ep CCD camera, which can image one square degree per frame. The CCD sensor is cooled to -20° C. The instrument has a limiting magnitude of 19.2. Sky conditions are usually moderately light-polluted. [3] [4] Plano-convex lenses of 75 mm were custom-made by Broughton. Other customizations include the telescope mount and Broughton's own "Scantracker" software to automate pre-programmed pointing and imaging sequences.: p. 322  [3] [5]

The telescope's timing precision is documented in the Minor Planet Center's document archives, which show Root Mean Square (RMS) residuals of less than 0.5 arcseconds, with many observations recorded at near-zero arcsecond error. [6] Timing precision is crucial for telescopes on Earth to be able to coordinate data, and it is also important in the ability to calculate the size and shape of objects accurately during occultations. [7]

Minor planet discoveries

Reedy Creek Observatory has discovered more than 800 asteroids.: pp. 322-325  [3] Among the numbered asteroids credited to this observatory are: [8]

Occultation data from Pluto

The observatory has contributed data from two occultations of Pluto. The first occultation occurred on 12 June, 2006. The data was used to establish new information regarding Pluto's atmosphere. Among other discoveries, Pluto's surface nitrogen frost was judged to be 1.2-1.7 K warmer in 2006 than measured during a previous occultation in 1988. The upper atmosphere of Pluto was shown to hold a steady temperature of ~100 K but there is in this portion of the atmosphere a temperature gradient that is "possibly the result of CO gas." [9]

The second occultation, which was a double occultation of the UCAC2 star 25370733 by Pluto and one of its moons, Charon, occurred on 22 June, 2008. Data from this occultation was used to fine-tune the calculated distance between the centers of Pluto and Charon (19,636 km). [10]

Occultation data from Quaoar

In 2022, during the first series of observed stellar occultations by a transneptunian object, Quaoar, field data from Reedy Creek Observatory collected at Mount Carbine, Queensland, along with data from the space telescope CHEOPS, helped establish the limits of a methane atmosphere on Quaoar as well as Quaoar's astrometric position to less than 1 milliarcsecond. CHEOPS observed the occultation in progress, but Reedy Creek Observatory, with its slightly different line of sight, did not, thus enabling the observatory to contribute "negative chord" data, allowing measurements to be far more precise than they otherwise would have been. [11]

The study's co-authors included Nobel laureate Didier Queloz.

During previous Quaoar occultations in 2018 and 2020, the observatory contributed light curve data that helped determine the width, depth, granularity, and orbital radius of an inhomogenous dense ring around Quaoar, one of only three such dense rings found around small bodies in the Solar System. [12] Analysis of the data from this study called for a revision of the traditional notion of the Roche limit, which places a limit on the distance at which a ring can exist away from its parent body before tidal forces will not prevent the accretion of its mass as a satellite.

Study data contributed by Reedy Creek Observatory and others suggested that the Roche limit can be redefined more appropriately as a minimum distance from a planetary body at which a satellite can likely exist, without disturbance from tidal forces from the parent, rather than as a maximum distance from a planetary body at which a ring can exist without accreting as a satellite. Quaoar’s ring exists at 7.4 radii from its parent body, well outside the traditional Roche limit at which rings were thought not to exist, thus prompting a revision to an accepted tenet of planetary physics. [12]

For its contributions to the study of the Quaoar occultations in the journals Nature and Astronomy & Astrophysics, Reedy Creek Observatory was included in the Nature Index as the 74th most highly ranked Australian institution in the physical sciences. [13]

See also

References

  1. ↑ M.P.C. staff (22 October 2025). "Minor Planet Discovery Sites". Minor Planet Center. International Astronomical Union. Archived from the original on 4 February 2026. Retrieved 4 February 2026.
  2. ↑ "List Of Observatory Codes". Minor Planet Center . Retrieved 28 May 2018.
  3. 1 2 3 Martin Mobberley (2011). Hunting and Imaging Comets. New York: Springer. pp. 322–325. ISBN   9781441969057 . Retrieved 1 February 2026.
  4. ↑ Dan Durda. "The 2002 Gene Shoemaker NEO Grant Recipients". The Planetary Society. Archived from the original on 5 February 2026. Retrieved 5 February 2026.
  5. ↑ "Occultation Software". The Trans Tasman Occultation Alliance. New Zealand: Royal Astronomical Society of New Zealand. Archived from the original on 5 February 2026. Retrieved 5 February 2026.
  6. ↑ M.P.C. staff (9 January 2001). "MPC Archive" (PDF). Minor Planet Center. International Astronomical Union. p. 32. Retrieved 5 February 2026.
  7. ↑ Kamiński, K.; Weber, C.; Marciniak, A.; Żołnowski, M.; Gędek, M. (2023). "Reaching Submillisecond Accuracy in Stellar Occultations and Artificial Satellite Tracking". Publications of the Astronomical Society of the Pacific. 135 (1044): 025001. arXiv: 2301.06378 . Bibcode:2023PASP..135b5001K. doi:10.1088/1538-3873/acacc8.
  8. ↑ Lutz D. Schmadel and International Astronomical Union (2003). Dictionary of Minor Planet Names (Fifth ed.). Heidelberg, Germany: Springer Verlag. ISBN   9783540002383 . Retrieved 1 February 2026.
  9. ↑ E.F. Young; R.G. French; L.A. Young; C.R. Ruhland; M.W. Buie; C.B. Olkin; J. Regester; K. Shoemaker; G. Blow; J. Broughton; G. Christie; D. Gault; B. Lade; T. Natusch (26 September 2008). "Vertical Structure in Pluto's Atmosphere From the 2006 June 12 Stellar Occultation". The Astronomical Journal. 136 (5): 1757–1769. Bibcode:2008AJ....136.1757Y. doi:10.1088/0004-6256/136/5/1757 . Retrieved 1 February 2026.
  10. ↑ B. Sicardy; G. Bolt; J. Broughton; T. Dobosz; D. Gault; S. Kerr; F. Benard; E. Frappa; J. Lecacheux; A. Peyrot; J.P. Teng-Chuen-Yu; W. Beisker; Y. Boissel; D. Buckley; F. Colas; C. de Witt; A. Doressoundiram; F. Roques; T. Widemann; C. Gruhn; V. Batista; J. Biggs; S. Dieters; J. Greenhill; R. Groom; D. Herald; B. Lade; S. Mathers; M. Assafin; J. I. B. Camargo; R. Vieira-Martins; A. H. Andrei; D. N. da Silva Neto; F. Braga-Ribas; R. Behrend (14 January 2011). "Constraints on Charon's Orbital Elements From the Double Stellar Occultation of 2008 June 22". The Astronomical Journal. 141 (2) 67: 1–16. Bibcode:2011AJ....141...67S. doi:10.1088/0004-6256/141/2/67 . Retrieved 1 February 2026.
  11. ↑ Morgado, B. E.; Bruno, G.; Gomes-Júnior, A. R.; Pagano, I.; Sicardy, B.; Fortier, A.; Queloz, Didier; Broughton, J.; Benz, Willy [in French]; et al. (August 2022). "A stellar occultation by the transneptunian object (50000) Quaoar observed by CHEOPS". Astronomy & Astrophysics . 664: L15. Bibcode:2022A&A...664L..15M. doi:10.1051/0004-6361/202244221 . Retrieved 12 February 2026.
  12. 1 2 Morgado, B. E.; Sicardy, B.; Braga-Ribas, F.; Ortiz, J.L.; Salo, L.; Vachier, F.; Desmars, J.; Pereira, C.L.; Santos-Sanz, P.; Sfair, R.; de Santana, T.; Assafin, D.; Vieira-Martins, R.; Gomes-Júnior, A.R.; Margoti, G.; Dhillon, V.S.; Fernandez-Valenzuela, E.; Broughton, J.; et al. (8 February 2023). "A dense ring of the trans-Neptunian object Quaoar outside its Roche limit". Nature . 614 (7947): 239–243. Bibcode:2023Natur.614..239M. doi:10.1038/s41586-022-05629-6 . Retrieved 12 February 2026.
  13. ↑ David Swinbanks. "2024 Research Leaders: Leading institutions in physical sciences". Nature Index . London, England: Springer Nature. Archived from the original on 4 February 2026. Retrieved 4 February 2026.
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