Jan 8 asteroid occultation

BillYeung

    IOTA/IOTA-ES occultation update for
          (212) Medea / TYC 1839-00696-1 event on 2011 Jan 08, 11:47 UT
                  Visible from W USA, Japan, S China, SE Asia


Summary
-------
On 2011 Jan 08 UT, the 136 km diameter asteroid (212) Medea will occult a 10.0
mag star in the constellation Taurus for observers along a path across W USA,
Japan, S China, SE Asia.

In the case of an occultation, the combined light of the asteroid and the star
will drop by 2.7 mag to 12.7 mag (the magnitude of the asteroid) for at most
19.4 seconds.

This update is based on UNSO/Flagstaff astrometry for the asteroid kindly
provided by Alice Monet, TMO astrometry for the asteroid kindly provided by Bill
Owen, historical astrometry from the MPC files (via AstDys), and the following
catalogs for the star position: UCAC.

The event at a glimpse
----------------------
    * Rank: 99
    * date and approx. time of event: 2011 Jan 08, 11:32  - 2011 Jan 08, 11:59  UT
    * magnitude of target star: 10.0
    * magnitude drop [mag]: 2.7
    * estimated maximum duration : 19.4
    * Moon: 16 % sunlit, 98?distance
    * Sun: 145?distance
    * rough path description: W USA, Japan, S China, SE Asia

The occultation path
--------------------
    * approximate projected width [km]: 138
    * 1 sigma uncertainty interval [path widths]: +/- 0.26
    * 1 sigma uncertainty interval [seconds]: +/- 5.4
    * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .030 +/- .025)
    * 1 sigma uncertainty ellipse (major, minor, PA): ( .030", .025", 86?)
    * approx speed of asteroid's shadow [km/s]: 7.0044
    * website for maps:
          http://www.asteroidoccultation.com

PTS

I have prepared finder charts fromDSS for this event.

from Blue Plates, 15 x 15 arcmin

from RED Plates, 15 x 15 arcmin

from The Sky 6

PTS

Reminder.
The weather forcast is favorable.

PTS

PTS

I have added the position of the asteroid in this new finder chart (at about 4:00 pm today)

PTS

PTS

WC Yue, Gloria and I observed at Hokoon.
The asteroid was bright and visible together with several 13-mag stars around the target star.
When the two seemed merged, video recording was started using 30 fps.
analysis of the timing will be completed today, and report will be sent tomorrow.

PTS

PTS

Preliminary results:

start of occultation:  11:54:05.645 (+/-0.017) UTC
end of occultation:    11:54:20.306 (+/-0.017) UTC

Duration : 14.661s (+/-0.033 s)

PTS

daniel

Congratulations!

PTS

Hi,
Here is the preliminary reduced data of Asteroid Medea from this occultation event.


PTS

PTS

Patric Lau's data is also included.

PTS