2026 Asteroidal Occultations of Selected Categories - New 2025 December 31
The text of our full asteroidal occultation section for the 2026 RASC Handbook is posted here
Only a separate expanded page for Special Main Belt occultations will be posted
Maps and Tables for all categories EXCEPT for the special MB events are given in a presentation .pdf and the Handbook text .pdf linked below; that's also the case for the 2026 Occult input files
These occultations are described and illustrated (in maps and tables) in this 2026 predictions presentation that is modified from one given at the 2025 IOTA meeting. The maps and tables for the bright main belt occultations are on slides 3 and 4 of the 2026 predictions presentation linked to above, and those for the other categories follow them in a similar form. But in this file, I include, starting at slide 7, 7 slides explaining the challenges and special value of occultations by near-Earth asteroids (NEAs), especially by potentially hazardous asteroids (PHAs). Links to the .xml input files used by the Occult program, for main-belt and other categories of occultations (whose best events are also mapped and tabulated in the 2026 predictions presentation) are given below, including hundreds or even thousands of observable events worldwide, and usually including North American subsets of them. A map and table of the better 2026 North American occultations by special main-belt (MB) asteroids are on slides 14 and 15 of the presentation; they are the ones portrayed on pages 248 and 249 [xxCheck] of the Handbook. However, many more asteroids have been added in a further update of that work, and new maps and tables created that you will be able to find in a new Web page for them that will be added soon; in the meantime, read the 2025 Web page and its .pdf document with link near the top of that page to see much information about the new objects added, many being close binaries discovered during occultations, including several found since the Handbook information was generated in 2024 August. The Occult input files for special main-belt asteroids linked to below include some new asteroidal satellite discoveries made since the ones for 2025 last posted in late July 2025, but even more have been discovered since then that will be included when the 2026 special MB page is added sometime in mid January 2026. _____________________________ Except for the special MB asteroids, we will not be posting pages for the other categories (bright MB events, NEAs, Trojans, and distant objects, as we did ne for 2022, 2023, and 2024. It's too much work for us to prepare and update all those separate pages, so this year, like for 2025, we will not be doing that; so instead some links are given to the 2024 pages that have some general informstion applicable to their catagories. If anyone else wants to prepare any of them, we will help teach them how. Basic explanations of all categoris are given on pages 243-251 of the Handbook, so we provide in this .pdf document with the Handbook text, as we provided it in our last update on 2025 Sept. 1; a few minor editorial changes may have been made after that. It has the titles of the maps and tables to show where they should be, but you need to consult the 2026 presentation file with link above to see them. _ _ _ _ _ OCCULT INPUT FILES FOR 2026: Use of these files to generate your own predictions is described here. When you open these files with your Web browser, you should get a display that looks like this. The larger files may take a couple of minutes to show this appearance, showing a messed-up display before then. Once the proper view appears, right-click anywhere on the display, then "Save as" to a directory on your computer; the best directory is the \Asteroid\ subdirectory in your Occult\ directory. nam26all.xml with 2671 North American main belt events to mag. 10.3 filtered to remove events with errors greater than 0.4 path widths but also including several occultations by major planets and their satellites All2026.xml, Worldwide version of the above file with 28231 occultations filtered to remove events with errors greater than 0.4 path widths - for the MB events, prediction maps and some data are available at https://www.asteroidoccultation.com/. Occultations by major planets and by their main satellites: Worldwide major planet/moon events including all Galilean sat. 1849 events. Worldwide major planet/moon events with mag. drop less than 0.2 excluded, 1506 events. The above include cases with high RUWE and a few (mainly valuable irregular moons events) with relatively large path errors. Occult Watcher is the best way to find out about upcoming events near your location; it includes the latest orbit updates from the JPL Horizons online system. You can learn about and obtain the software at this link. __________________________ INPUT FILES FOR OTHER CATEGORIES OF OCCULTATIONS Near-Earth asteroids (NEAs to mag. 13.0, since these are brief events usually needing mobile equipment): Currently, worldwide files for most of these events can only be found on Preston's Web site at https://www.asteroidoccultation.com/. Also, the selection for North America only considers the 20 most hazardous NEAs and a few others as described in the NEA section of the RASC 2025 text linked to above. North American 2026 selected NEA events, including Phaethon given in the 2026 presentation. We plan to add a more comprehensive Worldwide file with a N. American subset by late Jan. for a selected list of important NEAs. Using the lists of special MB objects as of 2025 mid-August (many more than in the late July 2025 update list): 2026 most special Main Belt occultations for N. America for the 2026 presentation map The rest of the files below have worldwide coverage to mag. 16: 2026 all special Main Belt occultations file too large for Occult or OK, filtered? 2026 all special Main Belt occultations to Mag. 15.0 The two below are for the Most Special MB subset 2026 Most special Worldwide Main Belt occultations 2026 Most special North American subset of the above The two below are for our selected list of over 100 Trojan asteroids 2026 Worldwide selected Trojan occultations 2026 selected Trojan North American subset of the above For explanation see special MB occultations covering the last part of 2025 from our page of occultations by special MB asteoids for 2025. __________________________ David and Joan Dunham, 2025 December 31 e-mail: iotadunham@yahoo.com and dunham@starpower.net cell phone: 301-526-5590