Found this on pastro. Interesting opportunity for those of us that
plan to be out and about on Sat night @ 9:42 - 9:45pm.
Asteroids with moons, ya say?
-Tony
> If the weather holds, there is a great opportunity for Bay Area
> observers to
> see the occultation of Asteroid Eugenia's satellite Petit-Prince by
> a bright
> star in Taurus this Saturday night about 9:45PM. See below for more
> details...
>
> Hank Sielski
>
> ---------- Forwarded message ----------
> From: David Dunham <dunham@No-Spam>
> Date: Wed, Mar 5, 2008 at 11:14 AM
> Subject: [IOTAoccultations] If in the s. USA, you might see a moon
> of an
> asteroid eclipse a bright star Sat. pm
> To: IOTAoccultations@No-Spam
>
> Those in the possible region of visibility of these events are
> urged to publicize this event as much as possible, via astronomical
> society list servers, science writers for public media, etc.
> ______________________-
>
> You could see a relatively bright star, easily seen with binoculars,
> wink out briefly as a moon of the asteroid (45) Eugenia covers it;
> this rare event will be visible across the southern USA Saturday
> evening, March 8. You could help determine the location of the moon
> relative to the asteroid more accurately than can be done directly
> with the largest telescopes on or near the Earth, if you can obsere
> this rare event. In 1977, astronomers laughed when Paul Maley and I
> suggested that asteroids might have small moons based on visual
> observations of eclipses of stars. In 1994, they stopped laughing
> when they saw Dactyl, the small moon of the asteroid (243) Ida in
> images returned from the Galileo spacecraft. Now, many dozens of
> moons of asteroids have been discovered, but only three times have
> confirmed eclipse timings been made when these moons covered stars,
> providing the most accurate information about them (all of those
> observervations were made in Japan). Saturday evening, March 8, you
> could join this very small number of people who have seen a star
> eclipsed by a moon of an asteroid.
>
> Eugenia will eclipse the 5.7-mag. star ZC 741 in Mexico and its
> moons will eclipse it in the southern USA.
>
> We could use your help to map the asteroid and its small moons.
> The eclipse (called "occultation" by astronomers) by either Eugenia
> or by its moons can be seen with binoculars, if you can find the
> star not far from Aldebaran in Taurus; we have sky charts that
> should make locating the star rather easy.
>
> The occultation by Eugenia, about 215 km in diameter, will last up
> to 12 seconds in its path crossing northern Mexico over Loreto, Baja
> California sur; Torreon; Saltillo; and Monterrey.
>
> The occultation by Eugenia's larger (about 13 km) moon, Petit-
> Prince, will last about 0.7 second in a path passing over central
> California (over the San Francisco Bay area), southern Nevada,
> northern Arizona and New Mexico, the Texas panhandle and southern
> Oklahoma, the Arkansas/Louisiana border area, and southern
> Mississippi.
>
> The occultation by Eugenia's smaller (about 6 km) moon, S/2004(45)1,
> also called Petite-Princesse, will be more difficult to observe,
> lasting about a third of a second in a narrow path passing over
> northern Mexico and southern Texas. The location of its path is
> especially uncertain, it might be almost anywhere between San
> Antonio and Brownsville, Texas.
>
> The star, number 741 in the Zodiacal Catalog and also known as SAO
> 94227 or HIP 23043 (other catalogs), is in Taurus about 5 degrees
> above and to the left of of Aldebaran. It can be easily located
> using all-sky charts and a blowup chart of the Hyades region of
> Taurus showing Aldebaran, the V-shaped Hyades cluster, and other
> stars visible with binoculars to find the unique group of 5 stars
> that includes ZC 741 as its brightest member; these charts are
> posted on the Web site of the International Occultation Timing
> Association (IOTA) devoted to occultations of stars by asteroids at
> http://www.asteroidoccultations.com/observations/NA/ (the box at the
> bottom has the charts, other useful links to path maps, and power
> point files that describe how to make observations. Also for
> making observations, with whatever you have available, see
> http://iota.jhuapl.edu/timng920.htm ; just knowing if an eclipse of
> the star occurred or not at your location can be important,
> especially if it did occur. For those interested in the details,
> the star's coordinates are J2000 RA 4h 57m 22.3s, Dec
> +17 deg. 09' 13".
>
> The International Occultation Timing Association (IOTA) needs as
> many observers as possible to try to time the occultations by
> Eugenia and its moons, to better determine their sizes, shapes, and
> relative orbits. If you are anywhere near the paths described above,
> you are encouraged to watch or record ZC 741 from 5:42 to 5:45 UT
> (Universal or Greenwich Mean Time) of March 9, or, in local time,
> Saturday evening, March 8, at 9:42 to 9:45 pm PST, 10:42 to 10:45 pm
> MST, and 11:42 to 11:45 pm CST. The Petit-Prince occultation might
> even be seen at low altitude in the Florida panhandle early Sunday
> morning, March 9, from 12:42 to 12:45 am EST. In Mexico, Kerry
> Coughlin, e-mail BajaKerry@No-Spam <BajaKerry%40gmail.com>, is
> coordinating observations
> in Baja California while Pedro Valdez Sada, e-mail
> pvaldes@No-Spam <pvaldes%40intercable.net>, is coordinating
> them in
> Nuevo Leon and
> nearby areas of northeastern Mexico. David Dunham, e-mail
> dunham@No-Spam <dunham%40starpower.net>, is coordinating plans
> for the
> observations of
> the occultations by the Eugenian satellites.
>
> Especially for the satellites, we need many observers set up at pre-
> determined distances across the path in a way that will cover the
> uncertainty zone of the path, which is considerably wider than the
> path itself. We need the locations of observers who will try it from
> home locations or from fixed observatories so that mobile observers
> can fill the gaps in the coverage that the fixed-site observers can
> provide. The interactive Google maps on Derek Breit's Web site at
> http://www.poyntsource.com/New/index.htm (click on "Spectacular
> Triple Asteroid Occultation - 45 Eugenia" near the top) also
> includes static maps showing the paths, with green lines showing the
> predicted central line, blue lines showing the northern and southern
> limits, red lines showing the "1-sigma" error limits, and gray lines
> showing the less likely "2-sigma" error limits. Read the
> information in the boxes for the interactive maps if you use them;
> they can be used to view the paths on detailed maps, satellite and
> in some cases aerial photography, and other map sources to almost
> any desired level of detail. Derek Breit's site also includes a list
> of stations and cities in and near the predicted path, listed in
> order of distance in kilometers from the predicted central line
> (distances north of the line are considered as negative), and for
> each gives the predicted time of the center of the occultation, the
> probability that an occultation will occur, and the local
> circumstances (mainly in this case, the altitude above the western
> horizon) of the event. Notice that the event will occur at about 12
> deg. altitude above the horizon along I-35 between Dallas and
> Oklahoma City, so observers in that area and farther east, where the
> altitude will be even lower, need to take care to find large open
> fields, the east sides of lakes, or otherwise places with an
> unobstructed view of the western horizon.
>
> To help publicize this event, and provide basic information and
> observing tips for timing it, Pedro Valdez Sada has prepared a
> 3.2-megabyte Power Point file in Spanish and English on the main Web
> site mentioned above. It concentrates on observing the occultation
> by Eugenia in Mexico but has useful general information for the
> satellite events in the U.S.A., also.
>
> Much information about observing occultations of all types is in
> "Chasing the Shadow: The IOTA Occultation Observer's Manual"
> available for free at
> http://www.poyntsource.com/IOTAmanual/Preview.htm .
>
> David Dunham, IOTA, 2008 March 5, 2 pm EST
--
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Received on Thu Mar 06 10:37:42 2008