2024 Occultations by Special Main-Belt Asteroids - Updated 2024 April 24

Occultation of EI Tauri by (253) Mathilde Apr. 28/29 - Help Complete NEAR's Work!

These occultations are described and illustrated in this .pdf document. 
It includes several hot links to external Web pages, but links to internal files, 
especially the .xml input files used by the Occult program, are given below. 
The map and table, and some other information given in the .pdf file, were
published on page 249 of the Observers Handbook for 2024, which has 
been available since last December. We apologize for being late in 
posting this online version for these events.
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The important occultation of EI Tauri by (253) Mathilde, half of which 
was imaged by NASA's NEAR spacecraft in 1997, is described here.
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OCCULTATIONS BY (10424) GAILLARD, A NEW PROBABLE BINARY ASTEROID

On January 14th, Jean-Francois Gout recorded this double occultation of a 
13.0-mag. star by this asteroid from Mississippi. In his account, he 
suggests that the asteroid might be binary and gives links to details 
of his observation and analysis. He found a good occultation of an 
11.0-mag. star on Mar. 26 at 1.4h UT visible from a path passing from 
Dallas to just north of Miami (as far as we know, that event was not 
observed). Vadim Nikitin notes that Gouts observation 
could be explained as a graze by a peanut-shaped object, but that was our 
first reaction to the double occultation by Queens last September which 
was confirmed to be a separated binary object by an occultation a couple 
of weeks later. More observations of occultations by Gaillard are needed 
to determine the nature of the object. I have found 135 occultations of 
stars brighter than mag. 16 that will occur during the rest of 2024, but 
most of those will occur over areas with few occultation observers. The 
Occult input file for these Gaillard events is linked to near the end of 
this page.
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OCCULTATIONS BY (90) ANTIOPE

This is a binary asteroid with equal large (~90km) components 171 km apart. 
Special procedures are needed to show paths of occultations by the separate 
components, which is crucial for these events; often only a miss by both 
components will occur at the central line of an uncorrected prediction.
Antiope will occult 8.8-mag. HIP 34749 on Aug. 19, only visible from part 
of northeastern Florida, but at Jacksonville, the occultation will occur 
at 8:30 UT but only 8 deg. above the eastern horizon, in azimuth 68 deg.; 
an unusually clear sky will be needed to observe that event from locations 
along the Atlantic coast. On Dec. 27 around 7h UT, Antiope will occult 
an 11.2-mag. star with the path from s. Brazil to s. Peru.
There will be 33 occultations of stars of mag. 14.0 or brighter visible 
around the world in 2024, but many of those are over oceans or other 
astronomically unpopulated places.
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As noted in the .pdf document, (52246) Donaldjohanson is a Lucy-mission main-belt 
asteroid flyby target on its way to the Jupiter Trojans, so observations of 
occultations by it will be valuable. No bright occultations by it will occur in 
North America in 2024, so none are shown on the map and in the table of the 
.pdf document. However, there will be occultations of 13th-mag. stars by the
object on Sept. 2 (WY,ND,nwMN, and swON), Sept. 5 (n. FL), and Oct. 5 (NS-sUT), 
but their durations are less than 0.15s, rather like NEA occultations, so large 
portable scopes will be needed to reliably detect these events. Worldwide, there
are 14 occultations by Donaldjohanson of stars of mag. 12.0 and brighter, and six 
of stars brighter than mag. 11.0. On Sept. 30 before 4h UT, Donaldjohanson will 
occult a 9.3-mag. star from a narrow path crossing Senegal to Chad.
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CORRECTIONS TO THE OBSERVERS HANDBOOK 2024

The USA edition of the 2024 RASC Observers Handbook left out the column 
labels for all of the tables of occultations by asteroids on pages 245 to 251, 
an error that crept in just before the print run and after (correct) galley 
proofs had been sent to me for review. Corrected .pdf pages are posted on 
the website of the RASC Handbook.

Another problem, spotted by Joan, is an updated link for Occult Watcher, on p. 246, 
7th line counting up from “Occultations by Near-Earth Asteroids” the link given 
there can not be used to access the current version of the software. After I 
submitted the old link, Steve Preston created a better page for Occult Watcher 
that gives much information about it, as well as the link for the current version. 
This update is noted on the RASC 2024 Handbook updates page.

Not yet on the RASC correction page are the following:

On p. 248, 2nd line of “Occultations by Special Main-Belt Asteroids”, there are 
no spaces between any of the words on that line. I’m not sure how this happened, 
it is OK (with appropriate spaces) in the Word file I submitted, but this error 
is in all of the proof .pdf’s that were sent to me in late August and early Sept. 
I should have seen it in those, but missed it, as apparently did all the other 
reviewers; Joan found this last night. In Table 3 on p. 249, the Deimos occultation 
listed on Sept. 23 will actually be on Oct. 7, and the Anitra occultation given as 
Oct. 7 will actually be on Nov. 7. 
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Much useful information is also given on a special page I set up for the 
Asteroids, Comets, and Meteors (ACM) conference held in Flagstaff, AZ last month. 
It includes a link to my presentation given there about NEA and other special 
occultations, to a much longer version of that presentation given on July 9 
by Zoom to the ChesMont Astronomical Society, to several abstracts and ePosters 
relating to occultations from the ACM Web site, and to much general occultation 
information suitable for those interested in getting started with observing
occultations.
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OCCULT INPUT .XML FILES FOR 2024

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.

For 123 special main-belt asteroid events to mag. 14 in N. America
Worldwide special main-belt events to mag. 14, 1907 occultations, 
  but does include (319) Leona, so use this file to find Leona occultations in your
  region. When you open this file with Occult, you can filter by asteroid number, so 
  just type "319" and check the box to its left under "Asteroid number" in the orange 
  box, second from the right side of "Selection Filters" and you'll list only the 
  occultations by Leona. For North America during the rest of 2024, the only Leona 
  path will cross only Key West, FL and some of the Bahamian islands on Apr. 1, with 
  the star mag. 13.4, and the star has a huge (8.9) RUWE. Worldwide, there are 43 
  Leona occultations during 2024; the best are occultations of 10th-mag. stars visible 
  from northern S. America on March 13 and April 6.

135 occultations by (10424) Gaillard to mag. 16 for the rest of 2024 worldwide.

The bright main-belt occultations page contains additional explanatory 
information not repeated here; it also has links to other pages, such 
as one for occultations by Near-Earth asteroids,
and for occultations by Trojan asteroids.
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David and Joan Dunham, 2024 January 29, updated April 17 and 24.
e-mail:  dunham@starpower.net
cell phone:  301-526-5590