Let me know if youâre interested in helping out for any of the events
mentioned below, or described at http://iota.jhuapl.edu/AZoccs.htm that has ;
been updated with events through April. We can always use help with the
multi-station deployments that we undertake. The two files mentioned below are
not attached; they can be provided upon request.
At 10:52pm MST Monday evening, Mar. 11, the 15x30-km asteroid (433) Eros will
occult 6.7-mag. SAO 114762 = HIP 33731, for at least 2s over Blythe, Calif.;
over Gila Bend and south of Tucson (over Green Valley). Detailed information
about the event, including maps, can be found on a special page for the event
at http://www.occultationpages.com/rasc/20190312_433Eros.html . The star, at ;
J2000 RA 7h 00m 25.0s, Dec +1 deg. 55â 53â, is in Monoceros. Finder charts
of different scales and other event details are at
http://www.asteroidoccultation.com/2019_03/0312_433_62652.htm . Eros was ;
thoroughly mapped by NASAâs NEAR-Shoemaker mission that rendezvoused with the
asteroid 19 years before this occultation. Observations will be useful to
refine Erosâ orbit relative to Gaia data for the star, and that will refine
the long-term orbit from that was determined from radiometric tracking of
NEAR-Shoemaker. Although weâre safe for at least the next million years, over
the remaining age of the Solar System, Eros has about a 50% chance of colliding
with the Earth, an event that would be worse than the Chixulub impact that
wiped out the dinosaurs. The current NWS forecast is for mostly cloudy/overcast
skies over Arizona, with somewhat less cloudiness around Gila Bend. Earlier, I
had planned to catch a flight to Oakland, Calif., and observe the event from
the San Joaquin Valley or the Bay Area where itâs expected to be clear, but
several others in that area should cover the event well enough there. As of
early tomorrow afternoon, if thereâs any chance of observing the occultation
from Arizona, we will try it near the path, probably from the Gila Bend area.
At 10:51pm MST Tuesday evening, Mar. 12, the 40-km Main Belt asteroid (396)
Aeolia will occult an 11.1-mag.star in Virgo, for at least 4s. The path crosses
s.w. AZ, passing over Yuma; we plan to deploy a few stations north and west of
Yuma, where clear skies are expected. The path also passes over Organ Pipe
Cactus Natâl Monument and the expected central line passes over Rio Rico,
just north of Nogales, where the sky may be half cloudy. The star, at J2000 RA
12h 27m 33.2s, Dec -6 deg. 59â 31â, is six deg. s.w. of Porrima (gamma
Virginis). Finder charts of different scales and other event details are at
http://www.asteroidoccultation.com/2019_03/0313_396_63346.htm . Like most ;
asteroids, Aeolia has never been visited by a spacecraft, and only one
occultation by it has been observed previously, on 2017 Dec. 27 by Paul Maley
(only one station), so we should be able to learn more about the size and shape
of the asteroid from this occultation.
Although lunar grazing occultations are of less interest now, there are three
good ones over central Arizona Wed. evening, March 13, listed below; the first
one passes over parts of Phoenix. These are not included yet on the AZoccs Web
page that only has asteroidal events. âmagâ is the starâs apparent
magnitude and âspâ is its spectral type. âCAâ is âcusp angleâ,
measured in deg. around the Moonâs disk from the northern (N) cusp; these are
all northern-limit grazes, so a total occultation disappearance will be visible
from everywhere south of the path, including the Gilbert Rotary Centenniel
Observatory (GRCO) for all 3. Observations are of some value, as all 3 stars
are in the Kepler2 program, the results of which are still being analyzed. A
fixed-space font needs to be used for the columns of the table to line up
properly.
Graze graze GRCO GRCO
MST Star mag sp CA D,MST CA Graze Path
22:15 SAO 77064 7.8 K2 1.5N 22:11 9N Sun CityâUsery Mtn Prk
23:01 ZC 790 6.8 F7 2.4N 22:52 18N n. Black Canyon City
23:48 ZC 793 6.2 G8 2.9N 23:39 22N s. Camp Verde
The path for SAO 77064 is shown in the attached .jpg map file. The good
multiple events zone is between the two dark gray lines; the most events should
occur nearest the southern of the dark gray lines. North of the northern dark
gray line, the Moon will narrowly miss the Moon and there will be no
occultation at all. South of the southern dark gray line, only a single
disappearance on the dark side is likely, but at least a D-R-D sequence is
possible, especially closer to the graze path. The predicted profile (.gif
file) is also attached, where the horizontal scale is time relative to central
graze, and the vertical scale is distance of the observer from the
smooth-(spherical)-Moon-model predicted northern limit line, which is the
northern dark gray line on the map.
The path for ZC 790 crosses county road 59 west of the exit from I-17, a little
south of Sunset Point. The path might also be accessed from FR 626 a little
west of its exit from AZ87 not far from Mt. Ord. Let me know if you might be
interested in observing this brighter event, and I can provide more details of
the path, which is a little tricky to determine due to the high elevation and
mountainous terrain. Curiously, the path for this graze and the previous one
intersect northwest of San Antonio, Texas, and the predicted profiles line up
much better there to produce a staggering number of occultations of both stars.
The sky is predicted to be clear there as well. A few observers may try to
observe there. I would have been interested, except that I have some important
business I need to take care of around noon on Wed., so if anything, Iâll be
trying to observe either this graze, or the previous one, from Arizona.
The path for even brighter (but lower altitude) ZC 793 crosses Fs 136 about 3
miles of dirt road from the exit of road 68D going east from exit 278 of I-17.
Iâm not sure that Fs 136 is really accessible, although a quick look with the
satellite view of Google Maps didnât show any gates or barriers (but on some
similar roads, Iâve seen barriers now that arenât shown in the older Google
Map images). The path also crosses the road to Tonto Natural Bridge State Park
off of Route 260 n.w. of Payson; that might be better. I can provide more
details of the path, which like the previous event, is a little tricky to
determine due to the high elevation and mountainous terrain.
At 7:34pm MST Thu. March 14, the 114-km Trojan asteroid (1173) Anchises will
occult an 11.5-mag. star in southernmost Leo for up to 6 seconds. The predicted
central line passes over Nogales, but with the prediction uncertainties, an
occultation is possible as far north as Tucson, so observers in that area are
encouraged to try to observe this event. Skies are expected to be clear, but
the altitude will be 18 deg. in the east (azimuth 105 deg.). The Sun will be 14
deg. below the eastern horizon, so it should be dark enough, but there will be
only a short time of dark-enough sky to acquire the target. Finder charts of
different scales and other event information are at
http://www.asteroidoccultation.com/2019_03/0315_1173_59546.htm . We hope to ;
observe it from/near Nogales, AZ, but could use help to try to observe it from
a 2 nd station a little farther north, to get a 2 nd chord across the asteroid.
See http://iota.jhuapl.edu/AZoccs.htm for asteroidal events through the end of ;
April, and for lunar occultations predicted for Gilbert, AZ for the rest of
2019.
David Dunham, dunham@xxxxxxxxxxxxx , 301-526-5590.
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