Lunar Grazing Occultation Maps for North America for 2025 - New 2024 Dec. 31
by Eberhard Riedel and David Dunham
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Occultation snd Spectacular Graze of Spica, 2024 November 27
New Version 5.0 of GRAZPREP for lunar occultations, especially grazes
Observations of grazing occultations still valuable, as M. Soma discussed at the 2023 IOTA meeting
A solar eclipse observed near the limits of central eclipse was the ultimate graze
We post here, the video of the 2023 Oct. 14th annular eclipse that we recorded near the s. limit and a presentation about it, and one about the 2024 April 8th total solar eclipse
The best lunar grazing occultations of 2025 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 2025 RASC Observer's Handbook. But many additional good lunar grazing occultations that will be visible from North America in 2025 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 2025. 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 but George Viscome's primer is better for current video and CCD camera techniques, although it concentrates more on asteroidal occultations with much less about lunar occultstions and grazes. _____________________________ Grazing occultations in North America during 2025 to about mag. 7.0 Table Map, Jan. 1 - Feb. 15 Map, Feb. 16 - July 15 Map, July 16 - 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. ______________________________ NEW GRAZPREP VERSION 5.0 FOR PREDICTING AND ANALYZING LUNAR TOTAL AND GRAZING OCCULTATIONS The maps were generated with E. Riedel's GRAZPREP program that you can download and generate your own predictions, including Google Earth files that, when used with Google Earth, show the lunar profile projected on the Earth's surface, allowing good selection of observing sites, as described by E. Riedel here and also on pages 16-19 of a brand new edition of Journal for Occultation Astronomy (JOA) that you can get here. On the following 15 pages (20-34) of that issue of JOA are maps and tables of grazing occultations for various regions of the world for 2025, and a worldwide map and table of partial occultations of major planets for the year. You are encouraged to download and use this valuable software at the first link of this paragraph; we used primarily GRAZPREP predictions to locate observing sites for last November's graze of Spica described in the next section. Much more about GRAZPREP 5.0 can be found in its manual, easier to use thsn Occult4, especially for grazes. ______________________________ The best graze in North America during 2024 occurred the morning of Nov. 27 when the Moon occulted Spica. Please find basic information and a brief account of the observations, as well as how Joan used PyMovie and PyOTE to determine accurate times of the recorded contacts of this spectacular event here. ______________________________ Path data for grazing, properly partial, occultations of planets There is only one occultation of a major planet by the Moon in North America good enough to obaerve its graze, and both its northern and southern limits are given in the map and table on pages 1 and 2 of the .pdf document. The path data for it is given in our table above is for the center of the planet. Since planets are not point sources like most stars, it is better to give data for two lines at each limit, 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 posted below, as generated with Occult 4. January 14, Mars, northern graze January 14, 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 value. ______________________________ 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 10th 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 2024 is here (but you will find there only the .pdf document that documents the brightest grazes; the more extensive maps and tables for many 2024 grazes were\will be removed to make room for the 2025 material). Predictions of grazing occulta- tions during 2025 within 200 miles of Blue Springs, Missouri during 2025 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. ___________________________________ GRAZING OCCULTATIONS DURING THE TOTAL LUNAR ECLIPSE OF 2025 MARCH 14 A table, map, and path data for 62 grazes of stars as faint as mag. 12.4 that will occur during the total lunar eclipse on March 14th, visible from the Americas, is below, similar in format to those for the other grazes during the year given above. Unless the eclipse is unusually dark, the grazes of stars fainter than 10th mag. will likely be unobservable, and even those are better if they occur near the center of the umbra than near its outer edge. The perccent sunlit of the Moon given in the table ia wrong, always given as "100E"; actually, it will be 0E during totality, which lasts from 6:25.9 to 7:32.0 U.T. Before that, from 5:09.4 to 6:25.9 U.T., the percent sunlit (the percent of the Moon's disk not in the umbra) will decrease from 100E to 0E, while after totality, from 7:32.0 to 8:48.3 U.T., the percent sunlit will increase from 0E to 100E. In the main graze path data, only two of brighter (9th mag.) eclipse grazes are given, path #40 and 41, which are paths #31 and 48, respectively, in the table and map below. Since there is no cusp during a lunar eclipse, in its place is given the eclipse phase, just specifying whether at the time the eclipse is total or partial. Table Map, March 14th TLE Lunar eclipse grazes are especially difficult to video record with our standard video and CCD cameras that are more sensitive in the red, which is the cclor of the umbra, making it overwhelmingly bright, washing out the fainter stars as they approach the lunar limb. ___________________________________ GRAZE OBSERVATIONS STILL NEEDED, BUT TOO MANY NOW IGNORE THEM 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. ___________________________________ THE ULTIMATE GRAZE, THE 2023 OCT. 14TH ANNULAR ECLIPSE AT THE S. LIMIT 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 interested. 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 convinced a few 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. __________________________________ THE 2024 APRIL 8TH TOTAL SOLAR ECLIPSE AT THE S. LIMIT The Dunhams had originally planned to observe this near the northern limit on the west side of Ft. Worth, Texas, but five days before, when they had to decide where to go, the weather forecasts for most of the path in Texas were poor, but very good for Maine. With help from Joan's sister, Gail, and her husband, Dan Knowles, they travelled to and observed the eclipse just north of Solon, Maine, about 3 km north of the predicted southern limit. An account of the trip, with several images, is in IOTA's Web page for the eclipse. More was shown in this presentation that David gave at the East Valley Astronomy Club meeting in Arizona in May 2024. __________________________________ ONE OF THE BEST GRAZE VIDEOS, 2017 ALDEBARAN, 5 STATIONS SYNCHRONIZED 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 at http://www.lunar-occultations.com/iota/iotandx.htm. 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 webmaster@lunar-occultations.com . ___________________________________ Dr. Eberhard Riedel IOTA-ES Public Relations Mobile +49 179 1253558 e-mail: E_Riedel@msn.com ___________________________________ Page set up by David and Joan Dunham on 2024 Dec. 31 Cell phone 301-526-5590 email dunham@starpower.net