2015-03-10

Asteroid Kleopatra occults 8mag Star - Updates

European skywatchers have a speacial treat ahead: On Thursday, March 12, 2015, around 01:08 UTC, main-belt asteroid (216) Kleopatra will occult a  8.1mag star in the constellation Crater. The event will be visible in parts of Britain, Benelux, Eastern France, Germany, the Alps region, Italy to Greece, although virtually all European amateur astronomers are urged to make observations.

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Update March 12, 11:00 UT: Success! Several observers across the continent (especially in NL, B, D and France, already submitted positive results. The star was occulted several seconds. Analysis will certainly take some time, but we can hope a nice profile of Kleopatra's shape will be out soon.

Update March 13: Preliminary chords are now available and are updated continuously:

Credit: Eric Frappa, euraster.net
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Map of occultation path. Credit: Oliver Klös, iota-es

(216) Kleopatra is thought to have a "dog-bone" shape, much like the oddly shaped comet "Chury" visited by Rosetta. It's own magnitude is 11.9. Observations (and accurate timings) by as many amateurs as possible are needed to determine more information about the asteroid's shape. The occulted star in question is 8.1mag HIP 54599 in the Crater constellation.

The occultation will take place on March 12, around 01:08 UTC/GMT (02:08 CET). The event will only mildly be disturbed by a waning moon, but there is a setback: HIP 54599 will be very low (around 5° for the central part of the occultation path) over the horizon.

Overview of the sky for central Europe at the time of occultation. Position of HIP 54599 is marked.

Observers within the red solid lines of the map are thought to see the occultation by the asteroid, those within the dashed line also have a chance due to uncertainties of the asteroid's orbit. Kleopatra also has two (known) moons, who might also cause occultations, as indicated in the map by green and blue lines. Have in mind that predictions about asteroid occultation paths are much more uncertain than those for solar eclipses, so observe even if you are located outside these lines. I cannot judge how accurate this map is - by experience I would take it as a recommendation only.

Finding cahrt for HIP 54599. The star should be visible in small telescopes or binoculars under clear and fairly dark skies.

An observation of the event can only be useful if some basic information is provided - e. g. precise location and timing information. Read this manual to learn how to observe and time asteroid occultations!

Path coordinates and more provided by Iota.

Any observation - positive and negative - should be reported here (report form).

Good Luck and Clear Skies!

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