Update for (409) Aspasia - October 18, 2001

Jan Manek's update

                      IOTA/IOTA-ES occultation update for
            (409) Aspasia / TYC 05688-00868-1 on October 18, 2001
             visible from England and S Scotland, N Netherlands,
                        Denmark, N Germany and S Sweden

Summary 

In the evening of October 18, 2001 a 10.9 mag star TYC 05688-00868-1 will be occulted by a 168 km asteroid (409) Aspasia. This update is based on USNO/Flagstaff and TMO astrometry for the asteroid and Tycho-2 star position.

The updated path shows no path shift or time correction compared to Edwin Goffin's nominal prediction.

The path of this occultation runs over Ireland in strong evening twilight ~18:01 UT, S Scotland and England around 18:01.3 UT. Thenafter north Netherlands, Denmark and baltic coast of Germany ~18:01.5 UT and S Sweden are in path. More to east the star is too low. Please check the path chart for details.

Faint star at low altitudes, but rather wide path, so there is a high chance for observers with larger telescopes.

The event at one glimpse:
 * date and approx. UT time of event: October 18, 2001 @ 18:01 UT (Euro)
 * magnitude of target star: 10.9
 * magnitude drop [mag]: 1.9
 * estimated maximum duration [s]: 5.7
 * path description: given above
 * Goffin's original chart reference: A01_1033

The occultation path:
 * approximate ground width [km]: 400
 * uncertainty [path widths]: 1.4
 * uncertainty in time [s]: 10
 * map: below
 * remarks: Path uncertainities are given according to nominal star
    position errors and expected asteroid positional accuracy.

Data for the target star:
 * name: TYC 05688-00868-1
 * constellation: Serpens
 * J2000 position [h,m,s; o,',"]: 18h 14m 49.704s; -14o 58' 03.34"
 * position source: Tycho-2
 * estimated accuracy ["]: 0.07" (0.04", 0.05")
 * V mag [mag]: 10.89
 * B-V [mag]: +0.27
 * remarks:
     Target star is in SE Serpens, close to border with Scutum and Sagittarius,
     about 3.5 degrees west of 4.7 mag star gamma Serpentis = SAO 161520.
     Target star is NW in a pair of almost equal magnotude star with only 1'
     separation.

Close finding chart (prepared in GUIDE7):
 * occulted star is in center - labeled with cross
 * field is 2.0x2.0 degrees
 * limiting magnitude is 12.5
 * labeled stars have indicated SAO numbers





Data for the minor planet:
 * general information:
     number, name: (409) Aspasia
     approx. diameter [km]: 168
 * orbital information
     orbit source: calculation Manek
     source of used astrometry: USNO/Flagstaff (Ron Stone), TMO (Bill Owen)
     number of used observations: 79 USNO, 12 TMO
     number of rejected observations: 6 USNO, 1 TMO
     time covered by the observations: 1998 07 02 - 2001 08 07
     rms residuals ["] (RA,DE): 0.07", 0.07"
     estimated positional accuracy at epoch of event ["]: 0.08"
     remarks:

Data for the event:
 * UT date and time of least geocentric approach: 18:00.5 UT
 * approx. V mag of minor planet at event [mag]: 12.6
 * geocentric parallax of minor planet ["]: 3.304
 * magnitude drop [mag]: 1.9
 * estimated maximum duration [s]: 5.7
 * apparent motion of minor planet ["/h]: 55.11
 * angular distance to moon, phase of moon [deg,%]: 42, 5%
 * remarks:

Calculator(s): Jan Manek





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