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ASTROMETRIC UPDATE:
OCCULTATION BY (54) ALEXANDRA - 2011 JUL 25

[Detailed Finder Charts]


Updated:   2011 Jun 08, 01:11 UT

Event Rank : 99

(The event Rank is a measure of the likelihood of observing an event, and is equal to the probability of at least one successful observation by a team of two observers spaced 1/8 path width just inside opposite sides of the predicted path. An event rank of 100 indicates that the prediction is expected to be very accurate).


THE UPDATED PATH

Note: The duration given in the line below is the interval during which the occultation shadow sweeps across the Earth - please see the minute markers on the map to determine the approximate time for your location.

Alexandra Update Map


On 2011 Jul 25 UT, the 160 km diameter asteroid (54) Alexandra will occult a 9.8 mag star in the constellation Auriga for observers along a path across northern Queensland and central Australia, low in the north-east shortly before morning twilight begins.

In the case of an occultation, the combined light of the asteroid and the star will drop by 2.1 mag to 15.6 mag (the magnitude of the asteroid) for at most 4.3 seconds.

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

Additional details of this and other events are available at Steve Preston's website at http://www.asteroidoccultation.com/

EVENT DETAILS SUMMARY : Data for the target star : Data for the minor planet : The Occultation Path :
 Occultation of HIP  25494 by 54 Alexandra on 2011 Jul 25 
                  Centre              Star  Star   Sun      Path Limits           Error Limits
  E. Longitude   Latitude      U.T.    Alt    Az   Alt    Limit 1    Limit 2    Limit 3    Limit 4
      o  '  "     o  '  "    h  m  s     o     o     o    o  '  "    o  '  "    o  '  "    o  '  "
                                                         Latitude   Latitude   Latitude   Latitude
    129  0  0   -28 53  3   20 16 14     3    51   -25  -29 57 38  -27 49 23  -30 36 52  -27 11 37
    130  0  0   -28 12 54   20 16 14     4    50   -24  -29 17 19  -27  9 25  -29 56 26  -26 31 44
    131  0  0   -27 32 50   20 16 14     5    50   -23  -28 37  3  -26 29 31  -29 16  3  -25 51 56
    132  0  0   -26 52 50   20 16 15     6    50   -22  -27 56 52  -25 49 42  -28 35 45  -25 12 14
    133  0  0   -26 12 57   20 16 15     7    49   -21  -27 16 47  -25 10  1  -27 55 32  -24 32 40

    134  0  0   -25 33 13   20 16 16     9    49   -20  -26 36 50  -24 30 29  -27 15 27  -23 53 15
    135  0  0   -24 53 38   20 16 16    10    48   -19  -25 57  2  -23 51  7  -26 35 32  -23 14  0
    136  0  0   -24 14 15   20 16 17    11    48   -18  -25 17 26  -23 11 57  -25 55 47  -22 34 57
    137  0  0   -23 35  5   20 16 18    12    47   -17  -24 38  2  -22 32 59  -25 16 15  -21 56  8
    138  0  0   -22 56  9   20 16 19    13    47   -16  -23 58 52  -21 54 17  -24 36 56  -21 17 33

    139  0  0   -22 17 29   20 16 20    14    46   -15  -23 19 58  -21 15 51  -23 57 53  -20 39 15
    140  0  0   -21 39  6   20 16 21    15    46   -14  -22 41 20  -20 37 42  -23 19  6  -20  1 14
    141  0  0   -21  1  1   20 16 22    16    46   -13  -22  3  1  -19 59 52  -22 40 37  -19 23 32
    142  0  0   -20 23 17   20 16 23    18    45   -12  -21 25  1  -19 22 21  -22  2 28  -18 46 10
    143  0  0   -19 45 53   20 16 24    19    45   -11  -20 47 22  -18 45 12  -21 24 40  -18  9 10

    144  0  0   -19  8 52   20 16 25    20    44    -9  -20 10  5  -18  8 26  -20 47 14  -17 32 32
    145  0  0   -18 32 14   20 16 27    21    44    -8  -19 33 12  -17 32  3  -20 10 11  -16 56 18
    146  0  0   -17 56  1   20 16 28    22    43    -7  -18 56 43  -16 56  5  -19 33 32  -16 20 28
    147  0  0   -17 20 13   20 16 30    23    43    -6  -18 20 40  -16 20 32  -18 57 19  -15 45  5
    148  0  0   -16 44 52   20 16 31    24    43    -5  -17 45  3  -15 45 27  -18 21 33  -15 10  8

Uncertainty in time = +/- 1 secs

Prediction of 2011 Jun  8.0


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