Lunar Grazing Occultation Maps for North America for 2024 - New 2023 Dec. 23

by Eberhard Riedel and David Dunham

Observations of grazing occultations still valuable, as M. Soma discussed at IOTA meeting

A solar eclipse observed near the limits of central eclipse is the ultimate graze

We post here, the video of the Oct. 14th annular eclipse we recorded near the s. limit and a recent presentation about it

The best lunar grazing occultations of 2024 in North America
are shown in a map and tables in this .pdf document. 
The map, tables, and text of the document are adapted from 
pages 171 to 174 of the 2024 RASC Observer's Handbook. But 
many additional good lunar grazing occultations that will be 
visible from North America in 2024 are shown in maps and tables 
with more detailed information given below. 

Below are links to maps and data for the brighter lunar grazing 
occultations in North America during 2024. There are 4 maps of 
populated parts of North America showing grazing occultations of 
stars brighter than mag. 7.0, that should be visible with small telescopes.

In the maps, the lines are: 

- nighttime dark limb: solid lines

- nighttime bright limb: dashed lines

- daytime dark- and bright limb: dotted lines

We use thick lines for all occulted bodies 1.5 mag. and brighter,
and for major planets, regardless of their magnitude.

Much information about observing occultations of all types is in 
"Chasing the Shadow:  The IOTA Occultation Observer's Manual" 
available for free download here.

Grazing occultations in North America during 2024 to mag. 7.0


Map, Jan. 1 - March 19
Map, March 20 - Aug. 31
Map, Sept. 1 - Oct. 15
Map, Oct. 16 - Dec. 31

Path data

On the maps, time tick marks are on the north side of southern 
limits and on the south side of northern limits, that is, on 
the side of the limit that has a total occultation. The tick 
marks are at integral 10-minute intervals of U.T., with the 
U.T. at the western end of the path being given in the table.
The Moon's shadow always moves from west to east across the map.
The paths end in "A" when the altitude above the horizon equals 
the star's or planet's magnitude, and it ends in "S" if the Sun 
altitude equals the negative of the star's magnitude. The path 
ends in "B" if the graze goes onto the sunlit side of the Moon.

Path data for grazing, properly partial, occultations of planets

The above only include grazes of stars. There are six limit 
lines for grazes of planets given in the map and table on
pages 1 and 2 of the .pdf document. The path data for 
the six grazes of planets that cross land on our North 
America map are given in separate files generated 
with the Occult4 program below. Since planets are not point 
sources like most stars, data for two paths are given, an 
inner limit where the planet is just completely covered only 
at the time of closest approach (the U.T. time given), and 
following it, an outer limit where the edge of the Moon just 
touches the limb of the planet at the time of closest approach. 
The inner and outer limit define the partial occultation zone, 
where the planet is partially but never completely covered 
during the graze; it is a few to several km wide, depending on 
the angular size of the planet and the distance to the Moon.
The partial occultation has its longest duration at the inner 
limit, near which mobile observers will want to travel to 
observe the phenomenon. The inner limit, or edge of the partial
occultation zone, is south of the outer edge for northern 
grazes and is north of the outer edge for southern grazes. 
Whether the graze is northern or southern can only be told 
by the N or S in the file name, or the same letters following 
the cusp angle (CA) given in the last column of the path data.

April 7, Venus, northern graze
June 27, Saturn, northern graze
  Since conditions for this event are good enough, the graze of 
  Titan, the 8th-mag. brightest moon of Saturn, might also be seen:
June 27, Titan, northern graze
September 17, Saturn, northern graze
September 17, Saturn, southern graze
November 11, Saturn, northern graze
December 18, Mars, southern graze

Although observations of partial occultations of planets have 
no current scientific value, they are included since they can be 
interesting to watch, and recordings of them can have educational 

These maps, table, and path data were published previously in 
the RASC Observer's Handbook, for example, on pages 174-178 of 
the 2021 Handbook. But starting with 2022, only one map of the 
brighter grazes for the whole year are published, while
these maps for many more grazes of stars of 7th mag. and 
brighter (but some fainter, to 9th mag., during total lunar 
eclipses) will be provided online, only at this Web site. 
During the gibbous phases, when glare is strong, especially 
near full moon, magnitude limits brighter than 7th are used.
A page like this for North American grazes during 2022 is here
and one for 2023 is here
(but you will find there only the .pdf document that documents 
the brightest grazes; the more extensive maps and 
tables for many 2022 (and early in 2024, the 2023) grazes 
were\will be removed to make room for the 2024 material), and 
one for North American grazes during 2021 is here.
Predictions of grazing occultations during 2024 within 200 miles of 
Blue Springs, Missouri during 2024 are here.

Other information described below is on Bob Sandy's page of the main lunar IOTA Web site.
These include predictions of total lunar occultations for 40 major 
North American cities, a list of all known successful grazing 
occultation expeditions, as published in Occultation Newsletter, 
that were conducted between 1974 and 1986.  Reduction profiles 
(plots of the observations relative to Watts' charts of the edge of 
the Moon), most prepared by Bob Sandy, are also available for many 
of the larger graze expeditions.


Dr. Mitsuru Soma described the continued importance of observations 
of grazing occultations of stars in his presentation at the 2023 
IOTA meeting. In the YouTube video of his talk, he voiced concern 
over the large drop in observations of grazes in recent years as 
observers worldwide concentrate much more on asteroidal events. 
His last slide shows how, since 2021, only in Japan have a large 
number of grazes been observed, while in Poland 2 were recorded, 
and only 1 in each of 10 other countries. We do not need large 
expeditions like in the 1960s and 1970s when details of the lunar 
profile were poorly known. Now we can generate detailed profiles 
using Kaguya and LRO voluminous laser altimeter measurements so 
observers can be directed to the best distances from the predicted 
limit lines to obtain a maximum number of contacts. Although good 
astrometric information can be obtained by only one observer, 
recordings from 2 or 3 stations, spaced 100m or more apart, can 
give better results. Especially the brighter stars often have poor 
Gaia data that can be improved with lunar graze observations; as 
Dr. Soma explained, close double stars often cause the Gaia astro-
metric errors that can be measured and quantified with graze data.

 - a preview of what might be done for the 2024 April 8th total solar eclipse

Not shown on this page is a prediction for the ultimate grazing 
occultation, one of the Sun that will occur on April 8. Similarly, 
in our 2023 grazes page, we did not include predictions for the annular 
solar eclipse of October 14th. A good prediction site, which takes 
into account both the topography of the Moon and the Earth, is 
Xavier Jubiers zoomable Google map for the 2024 APRIL 8th TOTAL SOLAR ECLIPSE. 
We used his similar map for ASE_2023 that we used to select our 
observation site in Mentmore, NM, a few miles west of Gallup and 
a similar distance west of the Arizona border. The coordinates of 
our 127mm telescope were: Latitude 35.50030 deg. N, Long. 108.85797 deg. W 
(GPS, from IOTA-VTI), altitude 1966m (from Google Earth, within  
a meter of the IOTA-VTI value). You can see the multitude of 
Bailys beads during the central 3 min. in our video recording.
Links to the full 7-minute video of our eclipse, and a couple of 
short videos of sunspot occultations, are on the 2023 graze page, 
but those videos will be removed in early 2024; they will be 
available upon request via a DropBox share after that, for those 

David and Joan Dunham gave a presentation about their observations 
at a meeting of the East Valley Astronomy Club, held in Gilbert, 
Arizona and online on 2024 Nov. 17. A .pdf of their presentation 
was shown; there is also a .pdf of the narration for the presentation.
At the end of the presentation, the prolonged visibility of Bailys beads and the 
chromosphere as seen from locations a km or so inside the path of a TOTAL SOLAR ECLIPSE 
was stessed, as shown in a great recording of the 2017 solar eclipse by Fred Bruenjes
from his home about 2 km n. of the southern limit of totality. Please watch it; 
it may convince some to observe from locations just inside the path edges of the 
2024 April 8th total solar eclipse. IOTA used to strongly encourage accurately timed 
video observations of solar eclipses from near the edges of the paths of totality or 
annularity, for measuring the solar diameter, but we came to realize the difficulty in 
deriving such information from such recordings, as noted in the presentation. 
Nevertheless, others are interested in obtaining such observations, mainly to improve 
predictions for future eclipse, and since this was the last annular eclipse visible 
from the USA until 2048, it was a last chance for us. Our success was payback for our 
failure at the 2012 annular eclipse, when we were misled by a hand-held GPS and ended 
up about 15 miles outside the zone of annularity.


On 2017 March 5 (4th local date), Andreas Gada led a team of 
observers to locations near a country club in Mississauga, 
Ontario, to record a grazing occultation of Aldebaran on the 
dark side of the crescent Moon. Video recordings of the event 
were obtained at five of the stations, and Andreas edited them 
to create this amazing synchronized composite video which 
clearly shows the multiple event grazing occultation phenomena
and how they change with the geographic spacing of the observers.

Total Lunar Occultation Predictions

Predictions of the better total lunar occultations worldwide (mainly  
for stars and planets of 3rd mag. and brighter) for hundreds of 
cities are given in a large box, "Upcoming Bright Star Occultation 
Events", on the left side of IOTA's lunar occultations Web page 
Clicking on the star name takes you to a Web page for the event 
with a small-scale map of the occultation's region of visibility 
at the top (on this map, the northern and southern limits of the 
region are shown as white lines when the event occurs at night, 
dark blue lines when it is in dusk or dawn twilight, and dotted 
red lines when it occurs during daytime; the turqoise curves on 
the right and left side show where the occultation disappearance 
and reappearance occur at moonrise and moonset). Below the map 
is some general information, followed by the predictions for the 
disappearance, and that is followed by similar information for
the reappearance. The cities are listed in alphabetical order by 
the two-letter country code, and by the city name for each country. 
For US cities, the state two-letter code is given after the city 
name, but the order is only by the city name, irrespective of in 
which state it is located. At the end, following the D and R 
information is a list of the longitudes and latitudes of all of 
the cities for which predictions are given. IOTA's lunar occulta-
tions Web page is maintained by Rob Robinson, email address .

Dr. Eberhard Riedel 
IOTA-ES Public Relations 
Mobile +49 179 1253558 

Page set up by David and Joan Dunham on 2023 Dec. 23
Cell phone 301-526-5590