RASNZ Occultation Section - May Occultation Update

ASTROMETRIC UPDATE:
OCCULTATION BY (348) MAY - 2003 DEC 17

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 Dec 17 UT, the 82 km diameter asteroid (348) May will occult a 9.5 mag star in the constellation Capricornus for observers along a path across SE Australia from Adelaide to Brisbane.

In the case of an occultation, the combined light of the asteroid and the star will drop by 5.8 mag to 15.3 mag (the magnitude of the asteroid) for at most 2.0 seconds.

This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Ron Stone, 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 : 83
(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 Dec 17, 09:53 - 2003 Dec 17, 09:57 UT
(Refer to map(s) for your own location)
Magnitude of target star : 9.5
Magnitude drop [mag] : 5.8
Estimated maximum duration [s] : 2.0
Phase of moon, angular distance : 43 % sunlit, 119° distance
Sun : 37° distance
Rough path description : SE Australia

Data for the target star :

Name : TYC 6910-00082-1
Constellation : Capricornus
J2000 position [h,m,s ; °,',"]: RA: 20 22 18.5802 DE: -24 58 48.710
Position source : Pos: UCAC2, pm: UCAC2, pi:
Standard error : RA,DE ["]: ( .015, .017 )
V mag [mag] : 9.5
Remarks : (none)

Data for the minor planet :

Number, name : (348) May
Approx. diameter [km] : 82
Approx. diameter [arcsec] : .029
Source of used astrometry : FASTT MPC (via Astdys)
Number of used observations : 514
Number of rejected observations : 18
Time covered by the observations : 1991 Feb 09 - 2003 Sep 16
1 sigma uncertainty ellipse (major, minor, PA) : 0.017, 0.008, 85°
Remarks : (none)
Update computed by : Steve Preston, Medina, Washington, USA. (OrbFit).

The Occultation Path :

Approximate projected width [km] : 98
Uncertainty interval [path widths] : +/- 0.62 (1 sigma)
Uncertainty interval [seconds] : +/- 1.4 (1 sigma)
Uncertainty interval approx RA,DE ["] : (+/- .023 +/- .018) (1 sigma)
Uncertainty ellipse (major, minor, PA) : ( .023", .018", 87° ) (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  '  "
                                                         Latitude   Latitude   Latitude   Latitude
    110  0  0   -48 47 53    9 56  2    51   294    24  -49 18 46  -48 17 11  -49 57 22  -47 39 25
    111  0  0   -48 23 54    9 56  4    51   292    23  -48 54 52  -47 53  7  -49 33 35  -47 15 15
    112  0  0   -47 59 29    9 56  6    50   291    22  -48 30 33  -47 28 38  -49  9 22  -46 50 39

    113  0  0   -47 34 39    9 56  8    50   289    21  -48  5 47  -47  3 43  -48 44 43  -46 25 38
    114  0  0   -47  9 23    9 56 11    49   288    21  -47 40 36  -46 38 23  -48 19 38  -46  0 12
    115  0  0   -46 43 42    9 56 13    49   286    20  -47 15  0  -46 12 37  -47 54  7  -45 34 22
    116  0  0   -46 17 37    9 56 15    48   285    19  -46 48 59  -45 46 27  -47 28 11  -45  8  7
    117  0  0   -45 51  6    9 56 17    48   283    18  -46 22 33  -45 19 53  -47  1 51  -44 41 27

    118  0  0   -45 24 12    9 56 19    47   282    18  -45 55 42  -44 52 54  -46 35  5  -44 14 24
    119  0  0   -44 56 53    9 56 21    47   281    17  -45 28 28  -44 25 32  -46  7 55  -43 46 57
    120  0  0   -44 29 11    9 56 23    46   279    16  -45  0 49  -43 57 47  -45 40 22  -43 19  7
    121  0  0   -44  1  6    9 56 25    45   278    15  -44 32 48  -43 29 38  -45 12 24  -42 50 55
    122  0  0   -43 32 39    9 56 27    45   277    14  -44  4 23  -43  1  8  -44 44  4  -42 22 21

    123  0  0   -43  3 49    9 56 29    44   276    13  -43 35 37  -42 32 15  -44 15 21  -41 53 25
    124  0  0   -42 34 38    9 56 31    43   274    13  -43  6 28  -42  3  2  -43 46 16  -41 24  8
    125  0  0   -42  5  6    9 56 33    43   273    12  -42 36 59  -41 33 27  -43 16 50  -40 54 31
    126  0  0   -41 35 14    9 56 35    42   272    11  -42  7  9  -41  3 33  -42 47  2  -40 24 34
    127  0  0   -41  5  3    9 56 37    41   271    10  -41 36 59  -40 33 20  -42 16 55  -39 54 18

    128  0  0   -40 34 32    9 56 39    40   270     9  -41  6 30  -40  2 48  -41 46 28  -39 23 44
    129  0  0   -40  3 43    9 56 41    40   269     8  -40 35 43  -39 31 58  -41 15 43  -38 52 53
    130  0  0   -39 32 38    9 56 43    39   268     7  -40  4 38  -39  0 51  -40 44 39  -38 21 44
    131  0  0   -39  1 15    9 56 45    38   267     6  -39 33 17  -38 29 27  -40 13 19  -37 50 20
    132  0  0   -38 29 37    9 56 47    37   266     5  -39  1 39  -37 57 49  -39 41 42  -37 18 41

    133  0  0   -37 57 45    9 56 49    36   265     4  -38 29 47  -37 25 56  -39  9 50  -36 46 48
    134  0  0   -37 25 38    9 56 50    35   264     3  -37 57 41  -36 53 50  -38 37 44  -36 14 41
    135  0  0   -36 53 19    9 56 52    35   263     2  -37 25 21  -36 21 31  -38  5 24  -35 42 23
    136  0  0   -36 20 48    9 56 54    34   262     2  -36 52 50  -35 49  0  -37 32 52  -35  9 53
    137  0  0   -35 48  6    9 56 56    33   261     1  -36 20  7  -35 16 19  -37  0  9  -34 37 13

    138  0  0   -35 15 15    9 56 58    32   260     0  -35 47 14  -34 43 29  -36 27 14  -34  4 24
    139  0  0   -34 42 15    9 56 59    31   259    -1  -35 14 13  -34 10 30  -35 54 11  -33 31 27
    140  0  0   -34  9  7    9 57  1    30   259    -2  -34 41  3  -33 37 24  -35 21  0  -32 58 22
    141  0  0   -33 35 52    9 57  3    29   258    -3  -34  7 47  -33  4 11  -34 47 41  -32 25 12
    142  0  0   -33  2 32    9 57  4    28   257    -4  -33 34 25  -32 30 53  -34 14 16  -31 51 57

    143  0  0   -32 29  8    9 57  6    27   256    -5  -33  0 59  -31 57 32  -33 40 47  -31 18 38
    144  0  0   -31 55 41    9 57  7    26   256    -6  -32 27 29  -31 24  7  -33  7 13  -30 45 16
    145  0  0   -31 22 12    9 57  9    25   255    -7  -31 53 57  -30 50 41  -32 33 38  -30 11 53
    146  0  0   -30 48 42    9 57 10    24   254    -9  -31 20 23  -30 17 14  -32  0  1  -29 38 30
    147  0  0   -30 15 12    9 57 12    23   254   -10  -30 46 50  -29 43 47  -31 26 23  -29  5  8

    148  0  0   -29 41 44    9 57 13    22   253   -11  -30 13 19  -29 10 22  -30 52 47  -28 31 47
    149  0  0   -29  8 18    9 57 14    21   252   -12  -29 39 49  -28 37  0  -30 19 13  -27 58 29
    150  0  0   -28 34 56    9 57 16    20   252   -13  -29  6 23  -28  3 42  -29 45 42  -27 25 16
    151  0  0   -28  1 39    9 57 17    19   251   -14  -28 33  2  -27 30 30  -29 12 16  -26 52  8
    152  0  0   -27 28 29    9 57 18    18   251   -15  -27 59 47  -26 57 23  -28 38 55  -26 19  7

    153  0  0   -26 55 25    9 57 19    17   250   -16  -27 26 39  -26 24 24  -28  5 41  -25 46 13
    154  0  0   -26 22 30    9 57 20    16   250   -17  -26 53 39  -25 51 33  -27 32 35  -25 13 28
    155  0  0   -25 49 44    9 57 21    15   249   -18  -26 20 48  -25 18 52  -26 59 38  -24 40 52
    156  0  0   -25 17  8    9 57 22    14   249   -19  -25 48  8  -24 46 21  -26 26 52  -24  8 27
    157  0  0   -24 44 44    9 57 23    13   248   -20  -25 15 39  -24 14  2  -25 54 16  -23 36 14

    158  0  0   -24 12 33    9 57 23    12   248   -21  -24 43 22  -23 41 56  -25 21 53  -23  4 14
    159  0  0   -23 40 35    9 57 24    11   247   -22  -24 11 19  -23 10  3  -24 49 43  -22 32 28
    160  0  0   -23  8 52    9 57 25    10   247   -23  -23 39 30  -22 38 25  -24 17 48  -22  0 57
    161  0  0   -22 37 24    9 57 25     9   247   -24  -23  7 57  -22  7  3  -23 46  8  -21 29 41
    162  0  0   -22  6 13    9 57 26     8   246   -25  -22 36 41  -21 35 58  -23 14 44  -20 58 42

    163  0  0   -21 35 20    9 57 26     7   246   -26  -22  5 42  -21  5 10  -22 43 38  -20 28  1
    164  0  0   -21  4 44    9 57 27     6   245   -27  -21 35  1  -20 34 40  -22 12 49  -19 57 38
    165  0  0   -20 34 28    9 57 27     5   245   -28  -21  4 39  -20  4 30  -21 42 20  -19 27 35
    166  0  0   -20  4 32    9 57 27     4   245   -29  -20 34 37  -19 34 39  -21 12 11  -18 57 51
    167  0  0   -19 34 57    9 57 28     3   244   -30  -20  4 56  -19  5 10  -20 42 23  -18 28 29

    168  0  0   -19  5 44    9 57 28     2   244   -31  -19 35 37  -18 36  2  -20 12 56  -17 59 28
    169  0  0   -18 36 53    9 57 28     1   244   -32  -19  6 40  -18  7 17  -19 43 52  -17 30 50

Use these links for further information:
[Planetary Occultations] [Using the Predictions]
[Observing Details] [Timing Details] [Reporting Details] [Report Form]
[Asteroid Occultation Results]

[Site Map] [What's an Occultation?]
[Total Occultations] [Grazing Occultations] [Planetary Occultations] [Jovian Satellite Eclipses]
[Timing Occultations] [Reporting Observations] [Coming Events] [Software]
[About Us] [Publications] [Membership] [Links]

[Top of Page][Return to Home Page]