IOTA Occultation Campaigns

The COVID pandemic halted IOTA campaigns for organized group observations of specific events in 2020 and, as of this writing in early 2022, the campaigns have not restarted.

Special events, most requiring considerable experience in occultation observing, are being observed in a coordinated fashion. Some are announced on the user group forums, but others are with self-selected observers who are known to the individual coordinator as able and willing to observe. These include occultations by asteroids of critical importance for upcoming spacecraft missions or asteroids which have a potential for Earth impact.

Near Earth Asteroid Occultations

Observing occultations by NEAs is a very interesting and challenging endeavor, but a rewarding one. Results from occultations have led to better knowledge of their orbits and increased precision in determining whether or not a specific object may pose a risk of a damaging impact on Earth. Improvements in predicting the narrow occultation path across the Earth’s surface and improvements in observing equipment has brought precise timing of these very short events within the reach of more observers. There are multiple interesting events predicted for 2022 for which coordinated observing attempts are expected.

These occultations are described and illustrated (two maps and tables) in this pdf document. It includes several external Web pages, but links to internal files, especially the xml input files used by the Occult program, are given below.

  • Comprehensive PDC2021 paper of NEA occultations, pdf.
  • Didymos occultations presented at the 2022 Jan SBAG meeting, pdf

Occult Input XML Files for 2022

When these xml files are opened with a Web browser, the display should look like this. The larger files may take several minutes before displaying properly. Once the proper view appears, right click anywhere on the display, then “save as” to the Asteroid subdirectory under the Occult directory.

These are the files

  • For the 18 NEA events and tabulated in the main pdf document
  • Worldwide Didymos events to magnitude 13 are here
  • Worldwide events for selected NEAs to magnitude 14 are here
  • Worldwide events (5) for Phaethon in early 2022 are here
  • Worldwide events (24) for Phaethon in late 2022 are here

Lucy Mission Support

Marc Buie of SWRI has been running campaigns to support the Lucy spacecraft, launched on October 16, 2021. Experienced IOTA members have supported these campaigns and will continue to do so, especially for those events of brighter stars in North America.

The website has details of the past and future occultations by all of the Lucy mission target asteroids.


These special campaigns are generally not announced well in advance so they will not be promoted on these pages. However, well-qualified and interested observers are encouraged to communicate with the IOTA Officers or Secretary/Treasurer if they would like to be included in these campaigns. Please do note that these events are often near the limit of possibility using the portable telescopes and moderately-priced video equipment most of the observers have.