Lunar Grazing Occultation Maps for North America for 2023 - New 2023 May 23

by Eberhard Riedel and David Dunham

The best lunar grazing occultations of 2023 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 2023 RASC Observer's Handbook. But 
many additional good lunar grazing occultations that will be 
visible from North America in 2023 are shown in maps and tables 
with more detailed information given below. 

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.

Below are links to maps and data for the brighter lunar grazing 
occultations in North America during 2023. There are 6 maps of 
populated parts of North America showing grazing occultations of 
stars brighter than mag. 7.5, and some fainter during total lunar 
eclipses, that should be visible with small telescopes.

In the maps, the lines are black, yellow, or blue: 

- nighttime dark limb: black lines

- nighttime bright limb: yellow lines

- daytime dark- and bright limb: blue lines

I 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 2023 to mag. 7.5


Map, Jan. 1 - Feb. 25
Map, Feb. 26 - March 31
Map, April 1 - May 31
Map, June 1 - Aug. 31
Map, Sept. 1 - Oct. 25
Map, Oct. 26 - Dec. 31

Path data

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 will be published, while
these maps for over 200 grazes of stars of mag. 7.5 and 
brighter (but some fainter, to mag. 10.0, 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 7.5 are used.
A page like this for North American grazes during 2022 is here 
(but you will find there only the .pdf document that documents 
the brightest grazes during 2022; the more extensive maps and 
tables for over 200 2022 grazes were removed to make room for 
the 2023 material) and one for North American grazes during 2021 
is here.

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.

Predictions of grazing occultations during 2023 within 200 miles of 
Blue Springs, Missouri during 2023 are here.

Other information described below is on Bob Sandy's page of the main 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.

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 Dunham
Cell phone 301-526-5590