Lunar Grazing Occultation Maps and Totals Tables for North America for 2026 - New 2025 Dec. 27
by Eberhard Riedel and David Dunham
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
All 2026 North American Total Lunar Occultation Material from RASC Handbook is After the Graze Information
The best lunar grazing occultations of 2026 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 2026 RASC Observer's Handbook. But many additional good lunar grazing occultations that will be visible from North America in 2026 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 2026. There are 4 maps of populated parts of North America showing grazing occultations of stars brighter than mag. 6.5 (but fainter in the umbra of deep lunar eclipses), 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 2026 to mag. 6.5 Table Map, Jan. 1 - Mar. 31 Map, Apr. 1 - July 31 Map, Aug. 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. Some remarks about some of the grazes of stars in the above maps and tables are given after the section immediately below about the limits for the Oct. 6th occultation by Jupiter. ______________________________ GRAZING (PARTIAL) OCCULTATION OF JUPITER BY THE MOON, 2026 OCT. 6 This will be one of the most spectacular lunar occultations of 2026, but it is not in the above maps or tables that only include grazes of stars by the Moon. Both its northern and southern limits are given in the map and table on pages 1 and 2 of the .pdf document. But the limit lines there are 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 (or edge) 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 limits define the partial occultation zone, where the planet is partially but never completely covered during the graze; it is 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. Map, October 6, Jupiter, northern graze Map, October 6, Jupiter, southern graze Path data for the inner and outer edges of the partial occ'n zones October 6, Jupiter, northern graze October 6, Jupiter, 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. ______________________________ INFORMATION ABOUT SOME OF THE GRAZES OF STARS This refers to the event numbers given on the maps and in the tables in the top section above. #9: The star is ZC 440, epsilon Arietis that uses an average position of the two components of this interesting double. #10: The star is X54005, the secondary component only; if anyone wants to observe this graze, let us know. #32: This is during the March 3rd lunar eclipse in the Bahamas, where the Moon will be bright with 66% of its diameter sunlit (not in the umbra) at the start; this will be hard, since the graze will occur in the bright part of the umbra close to the edge, at umbral distances of 96-92% of the way from the center to the edge. The Univ. Time of central graze, and circumstances, as a function of longitude are in this Occult4 list. #33: This is a better event than #32, with the Moon about 30% sunlit and the umbral distance around 70%. Occult4 currently gives a wrong prediction for this graze, but we should be able to fix it before the eclipse occurs, and then we will update this page. #85: Grazprep shows this graze during the Aug. 28th partial lunar eclipse will likely be visible only from Mexico with about 30% of the Moon sunlit (not in the umbra) but rather near the bright edge of the umbra, and occuring on the bright uneclipsed part of the Moon when the path is in the USA so unobservable there. Accounts of observations of the 2024 November 27 graze of Spica, the annular solar eclipse of 2023 October, and of the total solar eclipes of 2024 April are included here, in the page for 2025 North American grazing occultations. ______________________________ 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 2026, 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. ______________________________ 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 2025 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 2026 material). 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. ___________________________________ 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. ___________________________________ 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 FOR 2026 The full text of the lunar occultations section of the 2026 RASC Observer's Handbook is here, but a few changes may be in the printed version that are not in the document here. The .pdf document shows one page of predictions for three of the 18 standard stations that was generated from an edited version of a plain text file generated by Occult4. Links to the six text files, each containing predictions for 3 standard stations, are below. Halifax, Montreal, and Toronto Winnipeg, Edmonton, and Vancouver Massachusetts, Washington (DC), and Chicago Miami, Atlanta, and Austin Kansas City, Denver, and New Mexico-Arizona Los Angeles, Northern California, and Honolulu Predictions of only a few of the brightest lunar occultations (mainly of 1st-mag. stars and major planets in North America) for hundreds of cities will be given on the left side of IOTA's lunar occultations Web page at http://www.lunar-occultations.com/iota/iotandx.htm. The longer worldwide lists provided there in previous years will no longer be provided. 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 occultations 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 2025 Dec. 27 Cell phone 301-526-5590 email iotadunham@yahoo.com