Update for (461) Saskia - August 17/18, 2003

Jan Manek's update

                 IOTA/IOTA-ES occultation update for
    (461) Saskia / TYC 6295-00523-1 = SAO 187727 on August 17/18, 2003
              visible from S Sweden, Denmark and S England

Summary 

In the night of August 17/18, 2003 a bright 9.3 mag star TYC 6295-00523-1 = SAO 187727 will be occulted by a 46 km asteroid (461) Saskia. This update is based on USNO/Flagstaff astrometry for the asteroid and UCAC2-beta star position.

The updated path shows ~6 path width north shift with time ~0.3 minutes earlier compared to Eric Frappa's prediction.

Updated path runs due to north shift over S Sweden ~20:29.6 UT, Denmark ~20:30.1 UT and S England ~20:31.6 UT. Also Ireland, Netherlands and very N Germany are close to the updated path. Event at low or very low altitudes. Please check the path chart for details.

Clear sky and good luck !!!

The event at one glimpse:
 * date and approx. UT time of event: August 17, 2003 @ 20:30 UT
 * magnitude of target star: 9.3
 * magnitude drop [mag]: 6.7
 * estimated maximum duration [s]: 5.4
 * path description: given above
 * Goffin's original chart reference: A03_XXXX

The occultation path:
 * approximate ground width [km]: 170
 * uncertainty [path widths]: 3.0
 * uncertainty in time [s]: 15
 * 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 6295-00523-1 = SAO 187727 = PPM 269362 = HD 178249
 * constellation: Sagittarius
 * J2000 position [h,m,s; o,',"]: 19h 08m 38.6767s; -21o 14' 34.987"
 * position source: recent UCAC2 beta
 * estimated accuracy ["]: 0.02" (0.01", 0.01")
 * V mag [mag]: 9.27
 * B-V [mag]: +0.10
 * remarks:
    Target star is in north Sagittarius, about 20' southwest of 2.9 mag star pi Sagittarii = SAO 187756.
    !!! IMPORTANT !!!
    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 about this.

Close finding chart (prepared in GUIDE8):
 * occulted star is in center - labeled with cross
 * field is 2.5x2.5 degrees
 * limiting magnitude is 12.5
 * labeled stars have indicated SAO numbers
 * remarks: Second chart shows 30' blowup to show correctly the star in field.










Data for the minor planet:
 * general information:
     number, name: (461) Saskia
     approx. diameter [km]: 46
 * orbital information
     orbit source: calculation Manek
     source of used astrometry: USNO/Flagstaff (Ron Stone)
     number of used observations: 111 USNO
     number of rejected observations: 26 USNO
     time covered by the observations: 1998 06 27 - 2003 07 25
     rms residuals ["] (RA,DE): 0.09", 0.10"
     estimated positional accuracy at epoch of event ["]: 0.06", 0.07"
     remarks:

Data for the event:
 * UT date and time of least geocentric approach: 20:31.9 UT
 * approx. V mag of minor planet at event [mag]: 16.0
 * geocentric parallax of minor planet ["]: 3.251
 * magnitude drop [mag]: 6.7
 * estimated maximum duration [s]: 5.4
 * apparent motion of minor planet ["/h]: 15.49
 * angular distance to moon, phase of moon [deg,%]: 105, 70%
 * remarks:

Elements for WinOccult:
============ cut here ===========================================
 2003 Aug 17
461 Saskia
20h 31.9m UT
95-00523-1   9.3   19  8 38.677-21 14 34.99TYC 6295-00523-1
16.0     46    5.4   2.705    -1.104     -2.97
   13.373 -21.241  -126.96   13.34
 20.5320  -.18243   .94370 -4.75282 -0.91437  0.00353  0.00032
2000    201.8593862003 8 9.00000301.040610157.4888661.442724  0.149237893.117805822.6525110610.45   0.15
RATE 1.7903200 .0000000 .0000000 .0000000 .00000000 .00000000 .00000000
============ cut here ===========================================

Calculator(s): Jan Manek








Path coordinates:
                  Centre              Star  Star   Sun      Path Limits           Error Limits
  E. Longitude   Latitude      U.T.    Alt    Az   Alt    Limit 1    Limit 2    Limit 3    Limit 4
                                                         Latitude   Latitude   Latitude   Latitude
    ...................................... shortened .............................................
      o  '  "     o  '  "    h  m  s     o     o     o    o  '  "    o  '  "    o  '  "    o  '  "
     22  0  0    63  4 51   20 28 50     6   187   -10   65  1 35   61 33 18   .. .. ..   55 21  2
     21  0  0    62 15 45   20 28 55     6   186   -10   64  0 38   60 50 11   .. .. ..   54 50 24
     20  0  0    61 30  8   20 29  0     7   186   -11   63  6 19   60  9 28   .. .. ..   54 20 46
     19  0  0    60 47 27   20 29  6     8   185   -11   62 16 55   59 30 52   .. .. ..   53 52  5
     18  0  0    60  7 20   20 29 11     9   184   -11   61 31 23   58 54 12   .. .. ..   53 24 21
     17  0  0    59 29 27   20 29 17     9   183   -11   60 49  3   58 19 19   .. .. ..   52 57 33
     16  0  0    58 53 36   20 29 24    10   182   -12   60  9 28   57 46  4   .. .. ..   52 31 40
     15  0  0    58 19 37   20 29 30    11   181   -12   59 32 17   57 14 21   .. .. ..   52  6 41
     14  0  0    57 47 20   20 29 37    11   180   -12   58 57 14   56 44  6   .. .. ..   51 42 35
     13  0  0    57 16 40   20 29 44    12   179   -12   58 24  9   56 15 14   .. .. ..   51 19 23
     12  0  0    56 47 30   20 29 51    12   178   -12   57 52 52   55 47 41   .. .. ..   50 57  2
     11  0  0    56 19 46   20 29 58    13   177   -12   57 23 14   55 21 25   .. .. ..   50 35 34
     10  0  0    55 53 24   20 30  6    13   176   -12   56 55 11   54 56 22   .. .. ..   50 14 57
      9  0  0    55 28 20   20 30 13    13   175   -12   56 28 36   54 32 29   .. .. ..   49 55 11
      8  0  0    55  4 32   20 30 21    14   174   -12   56  3 26   54  9 46   .. .. ..   49 36 16
      7  0  0    54 41 56   20 30 29    14   173   -12   55 39 37   53 48 10   66 35 47   49 18 11
      6  0  0    54 20 31   20 30 37    14   173   -11   55 17  5   53 27 40   64 51 49   49  0 56
      5  0  0    54  0 16   20 30 45    15   172   -11   54 55 49   53  8 13   63 49  5   48 44 30
      4  0  0    53 41  7   20 30 53    15   171   -11   54 35 45   52 49 50   62 59 59   48 28 54
      3  0  0    53 23  4   20 31  1    15   170   -11   54 16 52   52 32 28   62 18 47   48 14  7
      2  0  0    53  6  5   20 31  9    15   169   -11   53 59  7   52 16  7   61 43  6   48  0  9
      1  0  0    52 50  9   20 31 17    15   168   -10   53 42 31   52  0 46   61 11 38   47 46 59
      0  0  0    52 35 16   20 31 25    15   167   -10   53 27  0   51 46 24   60 43 37   47 34 38
   -  1  0  0    52 21 24   20 31 33    15   166   -10   53 12 33   51 33  1   60 18 31   47 23  5
   -  2  0  0    52  8 32   20 31 41    16   165    -9   52 59 11   51 20 35   59 55 59   47 12 21
   -  3  0  0    51 56 40   20 31 50    16   164    -9   52 46 52   51  9  7   59 35 45   47  2 24
   -  4  0  0    51 45 48   20 31 58    16   163    -9   52 35 34   50 58 35   59 17 37   46 53 15
   -  5  0  0    51 35 54   20 32  6    16   162    -8   52 25 18   50 49  0   59  1 27   46 44 54
   -  6  0  0    51 26 58   20 32 14    15   161    -8   52 16  3   50 40 21   58 47  6   46 37 21
   -  7  0  0    51 19  0   20 32 22    15   160    -7   52  7 47   50 32 38   58 34 30   46 30 35
   -  8  0  0    51 11 59   20 32 30    15   159    -7   52  0 32   50 25 50   58 23 33   46 24 37
   -  9  0  0    51  5 56   20 32 38    15   159    -6   51 54 16   50 19 57   58 14 13   46 19 27
   - 10  0  0    51  0 49   20 32 45    15   158    -6   51 49  0   50 14 59   58  6 27   46 15  4
   - 11  0  0    50 56 39   20 32 53    15   157    -5   51 44 42   50 10 56   58  0 11   46 11 29
   - 12  0  0    50 53 27   20 33  1    15   156    -5   51 41 23   50  7 49   57 55 26   46  8 42
   - 13  0  0    50 51 10   20 33  8    14   155    -4   51 39  3   50  5 36   57 52  9   46  6 42
   - 14  0  0    50 49 51   20 33 15    14   154    -4   51 37 41   50  4 17   57 50 20   46  5 30
   - 15  0  0    50 49 28   20 33 23    14   153    -3   51 37 19   50  3 54   57 49 59   46  5  5
    ...................................... 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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