2026 Asteroidal Occultations of Selected Categories - Updated 2026 March 31
The text of our full asteroidal occultation section for the 2026 RASC Handbook is posted here
NEW files for MANY MORE Special Main Belt occultations for the rest of 2026 are linked to below
A separate expanded page for Special Main Belt occultations will be posted soon
Occultations by Space Mission target (269) Justitia; Campaign for April 11am Event
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. The above cover all of 2026 but the information about the special MB asteroids is based on what we had for them in 2025 August that didn't include the many new objects that we have included in NEW "Rest2026" input files linked to below. 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 page 250 of the Handbook. However, many more asteroids have been added in this 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 in about 10 days; in the meantime, read the the 2025 Web page and its .pdf document with link near the top of that page. We now have newly-discovered moons of dozens of asteroids, as well as several with unusual shapes suggestive of contact binaries that deserve further scrutiny. Consequently, there are now 168 of these special asteroids for which we now have Occult prediction input files for the rest of 2026 given below that you can download and use Occult4 to generate lists for your observatory that can be used to prioritize your observations. About half (80) of these are copied into "MOST SPECIAL" files; these asteroids are considered the most likely to find important new information because of likely contact or near-contasct binaries, or higher chances of successful mobile efforts, especially if observed from two or more stations since the separations of the possible moons in these cases are mostly less than ten times the expected moon's diameter. _____________________________ 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. 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 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 ave 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. __________________________ JUSTITIA EXAMPLE FILES OF WHAT CAN BE DONE WITH THE INPUT FILES BELOW There is an interesting unusually slow occultation by (269) Justitia on the morning of April 11. The event, and the University of Virginia's large campaign for it, is described by Teddy Oakey in this .pdf file. The Apr. 11th path is shown in more detail in three zoomed in Occult Maps Path, Brazil to s.e. USA Path, southeastern USA Path, northcenral USA and Manitoba Map of 11 more Justitia occultations during the rest of 2026 in the USA to mag. 14.5 These are brighter than the April 11th event, but are all faster, especially the ones later in the year, as can be seen in the Occult table for them. __________________________ 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 2026 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. _ _ _ The NEW most comprehensive files for ALL 168 SPECIAL MAIN-BELT asteroids are given below FOR THE REST OF 2026 (after 2026 March 28): WORLDWIDE for ALL Special MB objects to mag. 15.5 with solar elongations greater than 16 deg.; since this has 29865 events, you MUST change your User Settings at the top left of the Occult Maintenance menu page; there, go down to section 11, "Asteroid occultations. search and display" and in the 2nd box, change the number of events allowed to 30000. North American subset of the above, 2287 events over the USA "lower 48", s. Canada, and n. Mexico. The NEW most comprehensive files for the 80 MOST SPECIAL MAIN-BELT asteroids for the rest of 2026, events deserving mobile efforts go get into or near their paths: this has 20044 events to mag. 16, so you might need to change your limit, as above for the "All" file, but if you quickly apply limits for your region after you first open this file, you may be all right with the usual 20000 events limit. WORLDWIDE for the MOST SPECIAL MB objects to mag. 16 with solar elongations greater than 15 deg.; North American subset of the above, 1534 events over the USA "lower 48", s. Canada, and n. Mexico. _ _ _ The below are retained ONLY if you want to check for events BEFORE MARCH 28 Using the lists of special MB objects as of 2025 mid-August (many more than in the late July 2025 update list, but many less than the above NEW files): 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, updated 2026 March 31 e-mail: iotadunham@yahoo.com and dunham@starpower.net cell phone: 301-526-5590