Update for (476) Hedwig - December 1, 2000

Jan Manek's update

                    IOTA/IOTA-ES occultation update for
            (476) Hedwig / TAC -05 12813 on December 1, 2000
        visible from N Portugal, NW Spain, S France and N Italy

Summary 

In the evening of December 1, 2000 a 10.8 mag star TYC 5207-00938-1 = TAC -05 12813 will be occulted by a 121 km asteroid (476) Hedwig. This update is based on USNO/Flagstaff and TMO astrometry for the asteroid and Tycho-2 star position.

The updated path shows ~3 path width south shift with no time correction compared to Edwin Goffin's nominal prediction.

The path of this occultation runs over N Portugal and NW Spain ~20:26.5 UT, south France and N Italy some seconds later. More eastern observers will have star too low for this faint star.

Keep in mind 2.5 path width uncertainity, extra travel to the occultation path isn't recommended, also as the event is very short and star rather faint. However observers within uncertainty limits should give a try from their permanent sites.

Good luck !

The event at one glimpse:
 * date and approx. UT time of event: December 1, 2000 @ 20:26.5 UT (Euro)
 * magnitude of target star: 10.8
 * magnitude drop [mag]: 3.0
 * estimated maximum duration [s]: 4.4
 * path description: given above
 * Goffin's original chart reference: A00_1227

The occultation path:
 * approximate ground width [km]: 150
 * uncertainty [path widths]: 2.5
 * uncertainty in time [s]: 15
 * map: below
 * remarks: Path uncertainities are given according to nominal star
    position errors and expected asteroid positional accuracy.
    !!!!!!!
    Circles along path indicates the centerline for this event.
    They are more accurate than the path limit lines.
    !!!!!!!

Data for the target star:
 * name: TAC -05 12813 = TYC 5207-00938-1
 * constellation: Aquarius
 * J2000 position [h,m,s; o,',"]: 21h 25m 06.791s; -05o 54' 58.11"
 * position source: Tycho-2
 * estimated accuracy ["]: 0.11" (0.07", 0.08")
 * V mag [mag]: 10.82
 * B-V [mag]: +0.75
 * remarks: 
     Target star is in north mid-west Aquarius, about 1.6 degrees west of
     2.9 mag star beta Aquarii = SAO 145457.

Close finding chart (prepared in GUIDE7):
 * occulted star is in center - labeled with cross
 * field is 4.0x4.0 degrees
 * limiting magnitude is 12.5
 * labeled stars have indicated SAO numbers





Data for the minor planet:
 * general information:
     number, name: (476) Hedwig
     approx. diameter [km]: 121
 * orbital information
     orbit source: calculation Manek
     source of used astrometry: USNO/Flagstaff (Ron Stone), TMO (Bill Owen)
     number of used observations: 48 USNO, 3 TMO
     number of rejected observations: 4 USNO
     time covered by the observations: 1998 02 12 - 2000 11 02
     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: 20:23.7 UT
 * approx. V mag of minor planet at event [mag]: 13.7
 * geocentric parallax of minor planet ["]: 3.307
 * magnitude drop [mag]: 3.0
 * estimated maximum duration [s]: 4.4
 * apparent motion of minor planet ["/h]: 51.59
 * angular distance to moon, phase of moon [deg,%]: 13, 28%
 * remarks: 

Calculator(s): Jan Manek





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