Call for Observations
Occultation of Betelgeuse by (319) Leona on 2023 Dec 12
The occultation of the red giant Betelgeuse (α Orionis) by the asteroid (319) Leona is an extraordinary opportunity to gain new knowledge not only about the asteroid but also about the star.
Due to the apparent angular size of Betelgeuse of about 50 mas and the asteroid of about 46 mas, it is possible that an annular occultation of the star will be observable. The profile of the asteroid will not completely cover the star disk and Betelgeuse will not disappear completely when observed with a telescope.
The shadow path of this stellar occultation runs in Europe from the east across Turkey, Greece, southern Italy and southern Spain and Portugal. The shadow then crosses the Atlantic and will pass southern Florida in the US.
The accuracy of the path prediction was improved with data of the very successful observations of occultations by (319) Leona on September 13 in Spain  and on September 16 in the US. JPL has updated the ephemerides for the asteroid. This new data and the astrometry for α Orionis from the USNO Bright Star Catolog (UBSC) was used for the following predictions.
Path prediction for the occultation of Betelgeuse by (319) Leona on Dec 12. Path calculated on 2023 Sep 30 with Occult V4.2023.9.26.
HIP 27989 (Path prediction on December 12:Betelgeuse, α Ori) by 319 Leona on 2023 Dec 12, at MSLa.kmz
Join the Observation Campaigns
Preparations are already underway in Italy and Spain to jointly observe this stellar occultation.
, the campaign is led by AstroCampania ETS- l'astronomia amatoriale in Campania:
Website of the Italian campaign
(website bilingual: Italian/English)
prepares the observing campaign on the Discord platform under the name OCULTAAS. Registration is necessary. (Spanish, communication in English possible)
, interested observers are informed on the website of GEMINI - Coopération Astronomes PRO-AM:
An introduction to the occultation by (319) Leona on Dec 12 by P. Slansky and B. Gährken has been published on the website of the Vereinigung der Sternfreunde (VdS):
IOTA informs about the current predictions in the US:
At the IOTA Meeting 2023 in July D. Dunham reported about this occultation and the observing possibilities in the US. A video recording of his presentation is available:
Presentation by D. Dunham
Upcoming (319) Leona Occultations - Pathfinders for the Betelgeuse occultation
On 2023 October 29 a star occultation by (319) Leona takes place over central and eastern Europe as well as northern Africa. UCAC4 502-021206 (Vmag = 14m9) will be occulted by Leona.
Successful observations by several stations will improve the predictions for the occultation on December 12.
Path prediction for the occultation of UCAC4 502-021206 by (319) Leona on Oct 29. Path calculated on 2023 Sep 30 with Occult V4.2023.9.26.
A few days before the occultation of Betelgeuse (319) Leona will occult UCAC4 489-016418 (Vmag = 12m2) on Dec 6. The path will cross Turkey, Greece and Malta in Europe and Tunisia, Libya, Algeria and Morocco in North Africa.
Path prediction for the occultation of UCAC4 489-016418 by (319) Leona on Dec 6. Path calculated on 2023 Sep 30 with Occult V4.2023.9.26.
All observers in and near the shadow paths are encouraged to participate in observing these occultations. Please contact the appropriate groups in your countries.
 Ortiz; J. L. et al., The stellar occultation by (319) Leona on 13 September 2023 in preparation for the occultation of Betelgeuse, https://doi.org/10.48550/arXiv.2309.12272