RASNZ Occultation Section - Metcalfia Occultation Update

ASTROMETRIC UPDATE:
OCCULTATION BY (792) METCALFIA - 2003 NOV 16

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 the time for your location)

On 2003 Nov 16 UT, the 60 km diameter asteroid (792) Metcalfia will occult a 11.2 mag star in the constellation Gemini for observers along a path across Australia from Cairns through the Simpson Desert and exiting at the Southern coast on the WA/SA border..

In the case of an occultation, the combined light of the asteroid and the star will drop by 2.7 mag to 13.8 mag (the magnitude of the asteroid) for at most 14.3 seconds.

This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Ron Stone, 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.

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

EVENT DETAILS SUMMARY :

Event Rank : 78
(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).
Date and approx. UT time of event : 2003 Nov 16, 17:59 - 2003 Nov 16, 18:34 UT
(Refer to map(s) for your own location)
Magnitude of target star : 11.2
Magnitude drop [mag] : 2.7
Estimated maximum duration [s] : 14.3
Phase of moon, angular distance : 54 % sunlit, 44° distance
Sun : 139° distance
Rough path description : Australia

Data for the target star :

Name : TYC 1882-00887-1
Constellation : Gemini
J2000 position [h,m,s ; °,',"]: RA: 06 23 08.2866 DE: +24 43 33.323
Position source : Pos: UCAC2, pm: UCAC2, pi:
Standard error : RA,DE ["]: ( .016, .019 )
V mag [mag] : 11.2
Remarks : (none)

Data for the minor planet :

Number, name : (792) Metcalfia
Approx. diameter [km] : 60
Approx. diameter [arcsec] : .053
Source of used astrometry : FASTT TMO MPC (via Astdys)
Number of used observations : 472
Number of rejected observations : 41
Time covered by the observations : 1929 Jun 11 - 2003 Oct 05
1 sigma uncertainty ellipse (major, minor, PA) : 0.040, 0.025, 100°
Remarks : (none)
Update computed by : Steve Preston, Medina, Washington, USA. (OrbFit).

The Occultation Path :

Approximate projected width [km] : 86
Uncertainty interval [path widths] : +/- 0.71 (1 sigma)
Uncertainty interval [seconds] : +/- 9.6 (1 sigma)
Uncertainty interval approx RA,DE ["] : (+/- .043 +/- .032) (1 sigma)
Uncertainty ellipse (major, minor, PA) : ( .043", .032", 99° ) (1 sigma)
Important Note regarding Accuracy:
The uncertainty interval in path widths given above (and shown as a 1-sigma uncertainty ellipse on the plot) refers to RMS deviation and is applied as a +/- range. In other words, a path uncertainty of 1.0 path widths means that the actual center of the asteroid's shadow path should fall within plus or minus 1 path width of the plotted path center. However path errors larger than 1 sigma have been observed so observers should be alert for primary occultations within plus or minus 3 sigma of the updated path.
Further, almost all asteroidal satellites discovered so far have been found within 10 diameters of the asteroid (since this distance is deep enough within the gravitational well to be stable over long timescales). Therefore, if monitoring for secondary events, observing out to about 10 path-widths either side of the predicted track remains worthwhile.
We therefore recommend that you monitor for events if your observing location is up to +/- 10 path-widths from the predicted track. If not monitoring for occultations by secondary bodies you should observe from locations within 3 sigma of the nominal path.
In terms of time, the predictions are now usually accurate to about +/- 0.3 minute so you should be most attentive during the predicted minute of the event. However if intending to catch a potential satellite occultation you should start observing at least 10 times the predicted central duration before the predicted closest approach time for your location, and continue for a similar period afterwards.
Path Co-ordinates :

                  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  '  "
                                                        Longitude  Longitude  Longitude  Longitude

    110 19 25   -54  0  0   18 33 51    11    11   -12  109 34 56  111  4  6  109 34 56  111  4  6
    111  2 27   -53  0  0   18 33 43    12    10   -13  110 18 46  111 46 20  110 18 46  111 46 20
    111 45 53   -52  0  0   18 33 34    13    10   -13  111  2 56  112 29  1  111  2 56  112 29  1
    112 29 44   -51  0  0   18 33 25    14     9   -14  111 47 28  113 12 11  111 47 28  113 12 11
    113 14  2   -50  0  0   18 33 15    15     8   -15  112 32 25  113 55 51  112 32 25  113 55 51

    113 58 49   -49  0  0   18 33  3    16     8   -15  113 17 47  114 40  2  113 17 47  114 40  2
    114 44  7   -48  0  0   18 32 52    17     7   -16  114  3 38  115 24 48  114  3 38  115 24 48
    115 29 58   -47  0  0   18 32 39    18     6   -16  114 49 59  116 10  9  114 49 59  116 10  9
    116 16 23   -46  0  0   18 32 25    19     6   -17  115 36 52  116 56  6  115 36 52  116 56  6
    117  3 25   -45  0  0   18 32 11    20     5   -17  116 24 20  117 42 43  116 24 20  117 42 43

    117 51  6   -44  0  0   18 31 56    21     4   -18  117 12 23  118 30  0  117 12 23  118 30  0
    118 39 27   -43  0  0   18 31 40    22     4   -18  118  1  5  119 18  0  118  1  5  119 18  0
    119 28 30   -42  0  0   18 31 24    23     3   -18  118 50 27  120  6 45  118 50 27  120  6 45
    120 18 17   -41  0  0   18 31  6    24     2   -19  119 40 32  120 56 16  119 40 32  120 56 16
    121  8 52   -40  0  0   18 30 48    25     2   -19  120 31 21  121 46 35  120 31 21  121 46 35

    122  0 15   -39  0  0   18 30 28    26     1   -19  121 22 58  122 37 46  121 22 58  122 37 46
    122 52 30   -38  0  0   18 30  8    27     0   -20  122 15 24  123 29 50  122 15 24  123 29 50
    123 45 39   -37  0  0   18 29 47    28   359   -20  123  8 42  124 22 50  123  8 42  124 22 50
    124 39 44   -36  0  0   18 29 26    29   358   -20  124  2 54  125 16 48  124  2 54  125 16 48
    125 34 49   -35  0  0   18 29  3    30   357   -20  124 58  5  126 11 48  124 58  5  126 11 48

    126 30 56   -34  0  0   18 28 40    31   357   -21  125 54 15  127  7 52  125 54 15  127  7 52
    127 28  9   -33  0  0   18 28 15    32   356   -21  126 51 30  128  5  3  126 51 30  128  5  3
    128 26 31   -32  0  0   18 27 50    33   355   -21  127 49 51  129  3 26  127 49 51  129  3 26
    129 26  5   -31  0  0   18 27 24    34   354   -21  128 49 23  130  3  4  128 49 23  130  3  4
    130 26 57   -30  0  0   18 26 57    35   352   -21  129 50 10  131  4  0  129 50 10  131  4  0


                                                         Latitude   Latitude   Latitude   Latitude
    131  0  0   -29 27 57   18 26 42    35   352   -21  -28 52 37  -30  3 54  -28 52 37  -30  3 54
    132  0  0   -28 30 45   18 26 14    36   351   -21  -27 56  2  -29  6  2  -27 56  2  -29  6  2
    133  0  0   -27 34 46   18 25 47    37   350   -21  -27  0 39  -28  9 26  -27  0 39  -28  9 26
    134  0  0   -26 40  1   18 25 19    38   349   -21  -26  6 28  -27 14  5  -26  6 28  -27 14  5
    135  0  0   -25 46 28   18 24 51    39   347   -20  -25 13 27  -26 19 59  -25 13 27  -26 19 59

    136  0  0   -24 54  7   18 24 23    39   346   -20  -24 21 37  -25 27  6  -24 21 37  -25 27  6
    137  0  0   -24  2 57   18 23 55    40   345   -20  -23 30 56  -24 35 25  -23 30 56  -24 35 25
    138  0  0   -23 12 58   18 23 27    40   344   -20  -22 41 24  -23 44 56  -22 41 24  -23 44 56
    139  0  0   -22 24  7   18 22 59    41   343   -20  -21 53  1  -22 55 38  -21 53  1  -22 55 38
    140  0  0   -21 36 25   18 22 30    41   341   -19  -21  5 44  -22  7 30  -21  5 44  -22  7 30

    141  0  0   -20 49 52   18 22  2    42   340   -19  -20 19 34  -21 20 31  -20 19 34  -21 20 31
    142  0  0   -20  4 25   18 21 33    42   339   -19  -19 34 31  -20 34 40  -19 34 31  -20 34 40
    143  0  0   -19 20  5   18 21  5    43   338   -18  -18 50 33  -19 49 57  -18 50 33  -19 49 57
    144  0  0   -18 36 50   18 20 37    43   336   -18  -18  7 39  -19  6 21  -18  7 39  -19  6 21
    145  0  0   -17 54 41   18 20  8    43   335   -17  -17 25 50  -18 23 51  -17 25 50  -18 23 51

    146  0  0   -17 13 36   18 19 40    44   334   -17  -16 45  4  -17 42 26  -16 45  4  -17 42 26
    147  0  0   -16 33 34   18 19 12    44   333   -16  -16  5 21  -17  2  5  -16  5 21  -17  2  5
    148  0  0   -15 54 36   18 18 44    44   331   -16  -15 26 41  -16 22 49  -15 26 41  -16 22 49
    149  0  0   -15 16 40   18 18 16    44   330   -16  -14 49  2  -15 44 36  -14 49  2  -15 44 36
    150  0  0   -14 39 46   18 17 48    44   329   -15  -14 12 24  -15  7 25  -14 12 24  -15  7 25

    151  0  0   -14  3 53   18 17 21    44   328   -14  -13 36 46  -14 31 16  -13 36 46  -14 31 16
    152  0  0   -13 29  1   18 16 53    44   326   -14  -13  2  9  -13 56  9  -13  2  9  -13 56  9
    153  0  0   -12 55  9   18 16 26    44   325   -13  -12 28 31  -13 22  2  -12 28 31  -13 22  2
    154  0  0   -12 22 17   18 15 59    44   324   -13  -11 55 52  -12 48 56  -11 55 52  -12 48 56
    155  0  0   -11 50 23   18 15 32    44   323   -12  -11 24 11  -12 16 49  -11 24 11  -12 16 49

    156  0  0   -11 19 28   18 15  6    44   322   -12  -10 53 29  -11 45 41  -10 53 29  -11 45 41
    157  0  0   -10 49 31   18 14 39    44   321   -11  -10 23 43  -11 15 32  -10 23 43  -11 15 32
    158  0  0   -10 20 31   18 14 13    44   320   -10  - 9 54 55  -10 46 21  - 9 54 55  -10 46 21
    159  0  0   - 9 52 29   18 13 47    43   318   -10  - 9 27  3  -10 18  7  - 9 27  3  -10 18  7
    160  0  0   - 9 25 23   18 13 21    43   317    -9  - 9  0  8  - 9 50 51  - 9  0  8  - 9 50 51

    161  0  0   - 8 59 14   18 12 56    43   316    -8  - 8 34  8  - 9 24 32  - 8 34  8  - 9 24 32
    162  0  0   - 8 34  0   18 12 31    43   315    -8  - 8  9  4  - 8 59  8  - 8  9  4  - 8 59  8
    163  0  0   - 8  9 42   18 12  6    42   314    -7  - 7 44 54  - 8 34 41  - 7 44 54  - 8 34 41
    164  0  0   - 7 46 19   18 11 41    42   314    -6  - 7 21 39  - 8 11  9  - 7 21 39  - 8 11  9
    165  0  0   - 7 23 50   18 11 17    41   313    -5  - 6 59 19  - 7 48 33  - 6 59 19  - 7 48 33

    166  0  0   - 7  2 17   18 10 53    41   312    -5  - 6 37 53  - 7 26 51  - 6 37 53  - 7 26 51
    167  0  0   - 6 41 37   18 10 29    41   311    -4  - 6 17 20  - 7  6  5  - 6 17 20  - 7  6  5
    168  0  0   - 6 21 51   18 10  6    40   310    -3  - 5 57 41  - 6 46 12  - 5 57 41  - 6 46 12
    169  0  0   - 6  2 59   18  9 43    40   309    -3  - 5 38 55  - 6 27 13  - 5 38 55  - 6 27 13
    170  0  0   - 5 45  0   18  9 20    39   309    -2  - 5 21  3  - 6  9  9  - 5 21  3  - 6  9  9

    171  0  0   - 5 27 55   18  8 58    39   308    -1  - 5  4  3  - 5 51 57  - 5  4  3  - 5 51 57
    172  0  0   - 5 11 42   18  8 35    38   307     0  - 4 47 55  - 5 35 39  - 4 47 55  - 5 35 39
    173  0  0   - 4 56 23   18  8 14    37   306     0  - 4 32 41  - 5 20 15  - 4 32 41  - 5 20 15
    174  0  0   - 4 41 56   18  7 52    37   306     1  - 4 18 18  - 5  5 43  - 4 18 18  - 5  5 43
    175  0  0   - 4 28 21   18  7 31    36   305     2  - 4  4 48  - 4 52  5  - 4  4 48  - 4 52  5

    176  0  0   - 4 15 39   18  7 10    36   305     3  - 3 52  9  - 4 39 19  - 3 52  9  - 4 39 19
    177  0  0   - 4  3 50   18  6 50    35   304     4  - 3 40 23  - 4 27 26  - 3 40 23  - 4 27 26
    178  0  0   - 3 52 52   18  6 30    34   304     4  - 3 29 29  - 4 16 25  - 3 29 29  - 4 16 25
    179  0  0   - 3 42 47   18  6 10    34   303     5  - 3 19 27  - 4  6 18  - 3 19 27  - 4  6 18
    180  0  0   - 3 33 35   18  5 51    33   303     6  - 3 10 16  - 3 57  3  - 3 10 16  - 3 57  3

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