Update for (86) Semele - October 21/22, 2002 - South Africa

Jan Manek's update

                    IOTA/IOTA-ES occultation update for
        (86) Semele / TYC 0020-00024-1 on October 21/22, 2002
                     visible from South Africa


Summary 

In the night of October 21/22, 2002 a 11.4 mag star TYC 0020-00024-1 will be occulted by a 127 km asteroid (86) Semele. This update is based on USNO/Flagstaff and TMO astrometry for the asteroid and recent UCAC star position.

The updated path shows no path shift with time ~0.3 minutes earlier compared to Edwin Goffin's nominal prediction.

Updated path runs over South Africa around ~00:17.2 UT with Kimberley on north limit and Bloemfontein on centerline. Expected brightness drop is 1.0 mag only, be careful. On the other hand, path is rather accurate and drive into occultation area would be probably successful. Please check the path chart for details.

Clear sky and good luck !!!

The event at one glimpse:
 * date and approx. UT time of event: October 22, 2002 @ 00:17 UT (South Africa)
 * magnitude of target star: 11.4
 * magnitude drop [mag]: 1.0
 * estimated maximum duration [s]: 14.3
 * path description: given above
 * Goffin's original chart reference: A02_1014

The occultation path:
 * approximate ground width [km]: 160
 * uncertainty [path widths]: 0.5
 * uncertainty in time [s]: 10
 * map: below
 * remarks: Path uncertainties are given according to nominal star
    position errors and expected asteroid positional accuracy.

Data for the target star:
 * name: TYC 0020-00024-1
 * constellation: Cetus
 * J2000 position [h,m,s; o,',"]: 01h 19m 28.7930s; +00o 38' 07.091"
 * position source: Recent UCAC position combined with Tycho-2 proper motion
 * estimated accuracy ["]: 0.02" (0.02", 0.01")
 * V mag [mag]: 11.35
 * B-V [mag]: +0.73
 * remarks:
    Target star is in northwest Cetus, about 9 degrees north of 3.6 mag star theta Ceti = SAO 129274.
    Purple stars in identification chart are so called 'non-star' objects in GSC; in dense fields
    the 'non-stars' are often real stars or blends of close pairs. Be careful.

Close finding chart (prepared in GUIDE7):
 * occulted star is in center - labeled with cross
 * field is 4.0x4.0 degrees
 * limiting magnitude is 13.0
 * labeled stars have indicated SAO numbers
 * remarks:





Data for the minor planet:
 * general information:
     number, name: (86) Semele
     approx. diameter [km]: 127
 * orbital information
     orbit source: calculation Manek
     source of used astrometry: USNO/Flagstaff (Ron Stone), TMO (Bill Owen)
     number of used observations: 81 USNO, 26 TMO
     number of rejected observations: 8 USNO, 3 TMO
     time covered by the observations: 1998 01 30 - 2002 10 10
     rms residuals ["] (RA,DE): 0.09", 0.09"
     estimated positional accuracy at epoch of event ["]: 0.06", 0.04"
     remarks:

Data for the event:
 * UT date and time of least geocentric approach: 00:21.7 UT
 * approx. V mag of minor planet at event [mag]: 11.8
 * geocentric parallax of minor planet ["]: 5.847
 * magnitude drop [mag]: 1.0
 * estimated maximum duration [s]: 14.3
 * apparent motion of minor planet ["/h]: 29.27
 * angular distance to moon, phase of moon [deg,%]: 18, 99%
 * remarks:

Elements for WinOccult:
============ cut here ===========================================
 2002 Oct 22
86 Semele
 0h 21.7m UT
20-00024-1  11.4    1 19 28.793  0 38  7.09TYC 0020-00024-1
11.8    127   14.3   1.504    -1.892     -7.15
  -15.833   0.636   170.72  -10.92
  0.3621   .15045  -.59756 -4.85435 -1.22401  0.00063  0.00101
2000    352.01908420021013.00000305.19576587.065963 4.802406  0.204361963.116445212.479562358.535   0.15
RATE 1.7914920 .0000000 .0000000 .0000000 .00000000 .00000000 .00000000
============ cut here ===========================================


Calculator(s): Jan Manek





Path coordinates:

                  Center               Altitude       Path Limits
  E. Longitude   Latitude      U.T.   star   sun   Limit 1    Limit 2
   ........................... shortened .............................
                                                   Latitude   Latitude
      o  '  "     o  '  "    h  m  s     o     o    o  '  "    o  '  "
     57  0  0   -24 44 23    0 12 59    17   -18  -24  0 46  -25 28 27
     56  0  0   -24 49 24    0 13  4    18   -19  -24  5 45  -25 33 29
     55  0  0   -24 54 40    0 13  8    19   -20  -24 11  1  -25 38 46
     54  0  0   -25  0 13    0 13 13    20   -20  -24 16 32  -25 44 20
     53  0  0   -25  6  1    0 13 18    21   -21  -24 22 20  -25 50  9
     52  0  0   -25 12  5    0 13 23    22   -22  -24 28 22  -25 56 14
     51  0  0   -25 18 25    0 13 29    22   -23  -24 34 41  -26  2 35
     50  0  0   -25 24 60    0 13 34    23   -24  -24 41 14  -26  9 11
     49  0  0   -25 31 50    0 13 40    24   -24  -24 48  3  -26 16  3
     48  0  0   -25 38 55    0 13 46    25   -25  -24 55  7  -26 23  9
     47  0  0   -25 46 15    0 13 52    26   -26  -25  2 26  -26 30 31
     46  0  0   -25 53 50    0 13 58    27   -26  -25  9 59  -26 38  7
     45  0  0   -26  1 39    0 14  4    27   -27  -25 17 47  -26 45 58
     44  0  0   -26  9 42    0 14 11    28   -28  -25 25 49  -26 54  3
     43  0  0   -26 18  0    0 14 18    29   -29  -25 34  5  -27  2 22
     42  0  0   -26 26 32    0 14 25    30   -29  -25 42 35  -27 10 56
     41  0  0   -26 35 17    0 14 32    31   -30  -25 51 18  -27 19 43
     40  0  0   -26 44 16    0 14 39    31   -31  -26  0 15  -27 28 43
     39  0  0   -26 53 28    0 14 46    32   -31  -26  9 26  -27 37 58
     38  0  0   -27  2 54    0 14 54    33   -32  -26 18 49  -27 47 25
     37  0  0   -27 12 32    0 15  1    34   -32  -26 28 26  -27 57  5
     36  0  0   -27 22 23    0 15  9    34   -33  -26 38 15  -28  6 58
     35  0  0   -27 32 26    0 15 17    35   -34  -26 48 16  -28 17  3
     34  0  0   -27 42 42    0 15 25    36   -34  -26 58 30  -28 27 21
     33  0  0   -27 53 10    0 15 33    37   -35  -27  8 56  -28 37 51
     32  0  0   -28  3 49    0 15 42    37   -35  -27 19 33  -28 48 33
     31  0  0   -28 14 40    0 15 50    38   -36  -27 30 22  -28 59 26
     30  0  0   -28 25 43    0 15 59    39   -36  -27 41 23  -29 10 30
     29  0  0   -28 36 56    0 16  8    39   -37  -27 52 34  -29 21 46
     28  0  0   -28 48 20    0 16 16    40   -37  -28  3 56  -29 33 12
     27  0  0   -28 59 55    0 16 25    41   -38  -28 15 29  -29 44 50
     26  0  0   -29 11 41    0 16 34    41   -38  -28 27 12  -29 56 37
     25  0  0   -29 23 36    0 16 43    42   -39  -28 39  5  -30  8 35
     24  0  0   -29 35 41    0 16 53    42   -39  -28 51  8  -30 20 42
     23  0  0   -29 47 56    0 17  2    43   -40  -29  3 21  -30 32 59
     22  0  0   -30  0 20    0 17 11    44   -40  -29 15 43  -30 45 25
     21  0  0   -30 12 53    0 17 21    44   -40  -29 28 14  -30 58  0
     20  0  0   -30 25 35    0 17 30    45   -41  -29 40 53  -31 10 44
     19  0  0   -30 38 25    0 17 40    45   -41  -29 53 41  -31 23 37
     18  0  0   -30 51 23    0 17 50    46   -41  -30  6 38  -31 36 38
     17  0  0   -31  4 30    0 17 60    46   -42  -30 19 42  -31 49 46
     16  0  0   -31 17 44    0 18  9    47   -42  -30 32 54  -32  3  3
     15  0  0   -31 31  6    0 18 19    47   -42  -30 46 13  -32 16 27
     14  0  0   -31 44 34    0 18 29    48   -42  -30 59 40  -32 29 57
     13  0  0   -31 58 10    0 18 39    48   -43  -31 13 13  -32 43 35
     12  0  0   -32 11 52    0 18 49    48   -43  -31 26 53  -32 57 19
     11  0  0   -32 25 40    0 18 59    49   -43  -31 40 39  -33 11  9
   ........................... shortened .............................

----------------------------------------------------------------------------
Jan Manek
Stefanik Observatory                Private :
Petrin 205                          Werichova 950
118 46  Praha 1                     152 00  Praha 5 - Barrandov     |_|_|
Czech Republic                      Czech Republic                  /   \
Internet : jan.manek@worldonline.cz                                |-O-O-|
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