Update for (516) Amherstia - November 19/20, 2000

Jan Manek's update

                    IOTA/IOTA-ES occultation update for
       (516) Amherstia / TYC 2309-00935-1 on November 19/20, 2000
    visible from Caucasus, S Ukraine, Moldova, N Romania, N Hungary,
         SW Slovakia, N Austria, S Germany and mid-north France

Summary 

In the night of November 19/20, 2000 a 10.0 mag star TYC 2309-00935-1 = SAO 55310 will be occulted by a 76 km asteroid (516) Amherstia. This update is based on USNO/Flagstaff and TMO astrometry for the asteroid and Tycho-2 star position.

The updated path shows ~6 path width north shift and time ~0.4 minutes earlier compared to Edwin Goffin's nominal prediction.

The path of this occultation runs over Caucasus ~0:29 UT, S Ukraine with Crym and Odessa ~0:29.5 UT, Moldova ~0:29.4 UT, N Romania ~0:30 UT, N Hungary ~0:30.3 UT, SW Slovakia ~0:30.4 UT, N Austria with Vienna ~0:30.6 UT, S Germany with Munich and Freiburg ~0:30.9 UT and mid-north France south of Paris ~0:31.5 UT.

Good weather and good luck !

The event at one glimpse:
 * date and approx. UT time of event: November 20, 2000 @ 00:30.5 UT (Euro)
 * magnitude of target star: 10.0
 * magnitude drop [mag]: 3.4
 * estimated maximum duration [s]: 5.0
 * path description: given above
 * Goffin's original chart reference: A00_1115

The occultation path:
 * approximate ground width [km]: 80
 * uncertainty [path widths]: 2.3
 * 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: SAO 55310 = PPM 67017 = TYC 2309-00935-1
 * constellation: Triangulum
 * J2000 position [h,m,s; o,',"]: 02h 09m 42.226s; +31o 36' 35.31"
 * position source: Tycho-2
 * estimated accuracy ["]: 0.04" (0.02", 0.03")
 * V mag [mag]: 9.95
 * B-V [mag]: +0.48
 * remarks: 
     Target star is in middle Triangulum, 3.4 degrees exactly south of 3.0 
     mag star beta Trianguli = SAO 55306. Just 23' east of target is 6.2 mag
     star 5 Trianguli = SAO 55338 and 2.5' east of target is 10.9 mag star
     TYC 2309-00944-1.

Close finding chart (prepared in GUIDE7):
 * occulted star is in center - labeled with cross
 * field is 3.0x3.0 degrees
 * limiting magnitude is 12.5
 * labeled stars have indicated SAO numbers





Data for the minor planet:
 * general information:
     number, name: (516) Amherstia
     approx. diameter [km]: 76
 * orbital information
     orbit source: calculation Manek
     source of used astrometry: USNO/Flagstaff (Ron Stone), TMO (Bill Owen)
     number of used observations: 47 USNO, 6 TMO
     number of rejected observations: 10 USNO
     time covered by the observations: 1998 02 05 - 2000 11 09
     rms residuals ["] (RA,DE): 0.08", 0.05"
     estimated positional accuracy at epoch of event ["]: 0.07"
     remarks: 

Data for the event:
 * UT date and time of least geocentric approach: 00:35.0 UT
 * approx. V mag of minor planet at event [mag]: 13.4
 * geocentric parallax of minor planet ["]: 3.529
 * magnitude drop [mag]: 3.4
 * estimated maximum duration [s]: 5.0
 * apparent motion of minor planet ["/h]: 30.28
 * angular distance to moon, phase of moon [deg,%]: 120, 36%
 * remarks: 

Calculator(s): Jan Manek





Path coordinates:
                                       Altitude
  E. Longitude    Latitude     U.T.    star  sun
   ........ shortened ..........................
      o  '  "     o  '  "    h  m  s     o     o
     56  0  0    39 26 10    0 28 31    19   -30
     54  0  0    40 14 10    0 28 36    21   -32
     52  0  0    40 59 30    0 28 40    23   -33
     50  0  0    41 42 14    0 28 45    24   -35
     48  0  0    42 22 25    0 28 50    26   -36
     46  0  0    43  0  8    0 28 55    28   -37
     44  0  0    43 35 26    0 29  1    29   -39
     42  0  0    44  8 23    0 29  7    31   -40
     40  0  0    44 39  3    0 29 12    32   -41
     38  0  0    45  7 29    0 29 18    34   -42
     36  0  0    45 33 45    0 29 24    35   -44
     34  0  0    45 57 53    0 29 31    36   -45
     32  0  0    46 19 57    0 29 37    38   -46
     30  0  0    46 39 59    0 29 43    39   -47
     28  0  0    46 58  2    0 29 50    41   -48
     26  0  0    47 14  7    0 29 57    42   -49
     24  0  0    47 28 18    0 30  4    43   -50
     22  0  0    47 40 35    0 30 10    45   -51
     20  0  0    47 51  1    0 30 18    46   -52
     18  0  0    47 59 37    0 30 25    47   -53
     16  0  0    48  6 24    0 30 32    49   -54
     14  0  0    48 11 22    0 30 39    50   -55
     12  0  0    48 14 33    0 30 47    51   -56
     10  0  0    48 15 58    0 30 55    52   -57
      8  0  0    48 15 35    0 31  2    54   -57
      6  0  0    48 13 26    0 31 10    55   -58
      4  0  0    48  9 30    0 31 18    56   -59
      2  0  0    48  3 47    0 31 26    58   -60
      0  0  0    47 56 16    0 31 35    59   -60
   -  2  0  0    47 46 57    0 31 43    60   -61
   -  4  0  0    47 35 47    0 31 52    62   -61
   -  6  0  0    47 22 47    0 32  1    63   -62
   -  8  0  0    47  7 55    0 32 10    64   -62
   - 10  0  0    46 51  8    0 32 19    65   -63
   - 12  0  0    46 32 26    0 32 28    67   -63
   - 14  0  0    46 11 45    0 32 38    68   -63
   ........ 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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