Update for (516) Amherstia - January 13/14, 2002

Jan Manek's update

                       IOTA/IOTA-ES occultation update for
         (516) Amherstia / HIP 36335 = SAO 60107 on January 13/14, 2002
        visible from S Russia, N Ukraine, S Belarus, N Poland, N Germany,
         N England, north of Ireland in Europe and north Florida in USA


Summary 

In the night of January 13/14, 2002 a bright 7.5 mag star HIP 36335 = SAO 60107 will be occulted by a 76 km asteroid (516) Amherstia. This update is based on USNO/Flagstaff, TMO and Geneva astrometry for the asteroid and Hipparcos star position.

The updated path shows ~1 path widths north shift with time ~0.1 minutes earlier compared to Edwin Goffin's nominal prediction.

Updated path runs over south Russia (Volgograd) ~0:09 UT, north Ukraine ~0:10 UT, south Belarus ~0:10.5 UT, north Poland (~100km north of Warsaw) and Szczecin around 0:11 UT, north Germany ~0:11.8 UT, north England ~0:12.7 UT, and north of Ireland. After passing over Atlantic Ocean path runs over north Florida ~0:19.1 UT with Jacksonville on north limit. Please check the path chart for details.

Bright star occultation with good prospects, although the event duration is not long, only ~5 seconds. Video or some other precision technique is recommended for recording this short event, otherwise a good stable mounted binocular is sufficient. Please inform others, living and observing in the path and uncertainty area to give a try.

Clear sky and good luck !!!

The event at one glimpse:
 * date and approx. UT time of event: January 14, 2002 @ 00:11 UT (Euro)
                                                         00:19 UT (North Am.)
 * magnitude of target star: 7.5
 * magnitude drop [mag]: 4.7
 * estimated maximum duration [s]: 5.3
 * path description: given above
 * Goffin's original chart reference: A02_0134

The occultation path:
 * approximate ground width [km]: 80
 * 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: HIP 36335 = SAO 60107 = PPM 72830 = TYC 2460-02215-1
 * constellation: Gemini
 * J2000 position [h,m,s; o,',"]: 07h 28m 44.0881s; +34o 26' 12.891"
 * position source: Hipparcos
 * estimated accuracy ["]: 0.02" (0.013", 0.007")
 * V mag [mag]: 7.46
 * B-V [mag]: +1.13
 * remarks:
     Target star is in north Gemini, 2.8 degrees NW of 2.0 mag star Castor =
     alpha Geminorum = SAO 60198 or 2.2 degrees west of 4.9 mag star omicron
     Geminorum = SAO 60247.

Close finding chart (prepared in GUIDE7):
 * occulted star is in center - labeled with cross
 * field is 3.0x3.0 degrees
 * limiting magnitude is 12.0
 * 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),
                                Geneva (Raoul Behrend)
     number of used observations: 83 USNO, 12 TMO, 21(2) Geneva
     number of rejected observations: 7 USNO, 2 TMO
     time covered by the observations: 1998 02 05 - 2002 01 03
     rms residuals ["] (RA,DE): 0.12", 0.11"
     estimated positional accuracy at epoch of event ["]: 0.08", 0.07"
     remarks: From Geneva positions were computed 2 means which were
       subsequently used for update.

Data for the event:
 * UT date and time of least geocentric approach: 00:13.0 UT
 * approx. V mag of minor planet at event [mag]: 12.2
 * geocentric parallax of minor planet ["]: 4.690
 * magnitude drop [mag]: 4.7
 * estimated maximum duration [s]: 5.3
 * apparent motion of minor planet ["/h]: 38.03
 * angular distance to moon, phase of moon [deg,%]: 166, 0%
 * remarks:

Calculator(s): Jan Manek








Centerline path and limit line 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  '  "
     50  0  0    46 52 49    0  8 46    48   -42   47 17  5   46 28 38
     48  0  0    47 32  0    0  8 56    50   -44   47 56  5   47  7 59
     46  0  0    48  9  9    0  9  5    51   -45   48 33  4   47 45 19
     44  0  0    48 44 19    0  9 14    52   -46   49  8  3   48 20 39
     42  0  0    49 17 32    0  9 23    54   -47   49 41  6   48 54  1
     40  0  0    49 48 50    0  9 33    55   -47   50 12 14   49 25 29
     38  0  0    50 18 16    0  9 42    56   -48   50 41 31   49 55  5
     36  0  0    50 45 53    0  9 51    57   -49   51  8 59   50 22 50
     34  0  0    51 11 42    0 10  0    58   -50   51 34 40   50 48 48
     32  0  0    51 35 47    0 10  9    59   -51   51 58 37   51 13  1
     30  0  0    51 58  9    0 10 18    60   -51   52 20 51   51 35 30
     28  0  0    52 18 51    0 10 27    61   -52   52 41 26   51 56 19
     26  0  0    52 37 54    0 10 36    62   -53   53  0 22   52 15 28
     24  0  0    52 55 20    0 10 45    63   -53   53 17 42   52 33  1
     22  0  0    53 11 11    0 10 54    64   -54   53 33 28   52 48 58
     20  0  0    53 25 30    0 11  3    64   -54   53 47 41   53  3 21
     18  0  0    53 38 16    0 11 12    65   -55   54  0 23   53 16 12
     16  0  0    53 49 32    0 11 21    66   -55   54 11 35   53 27 32
     14  0  0    53 59 19    0 11 30    67   -56   54 21 18   53 37 23
     12  0  0    54  7 37    0 11 38    67   -56   54 29 33   53 45 44
     10  0  0    54 14 28    0 11 47    68   -56   54 36 22   53 52 38
      8  0  0    54 19 53    0 11 56    68   -56   54 41 44   53 58  5
      6  0  0    54 23 52    0 12  5    69   -57   54 45 41   54  2  5
      4  0  0    54 26 25    0 12 14    69   -57   54 48 14   54  4 39
      2  0  0    54 27 32    0 12 23    69   -57   54 49 21   54  5 47
      0  0  0    54 27 15    0 12 31    70   -57   54 49  4   54  5 29
   -  2  0  0    54 25 33    0 12 40    70   -57   54 47 22   54  3 46
   -  4  0  0    54 22 25    0 12 49    70   -57   54 44 15   54  0 37
   -  6  0  0    54 17 51    0 12 58    70   -57   54 39 44   53 56  2
   -  8  0  0    54 11 52    0 13  7    70   -57   54 33 46   53 50  0
   - 10  0  0    54  4 25    0 13 16    70   -57   54 26 23   53 42 31
   - 12  0  0    53 55 31    0 13 25    70   -56   54 17 32   53 33 34
   - 14  0  0    53 45  9    0 13 34    69   -56   54  7 13   53 23  7
   - 16  0  0    53 33 17    0 13 43    69   -56   53 55 26   53 11 11
   - 18  0  0    53 19 54    0 13 52    69   -56   53 42  8   52 57 43
   - 20  0  0    53  4 59    0 14  2    68   -55   53 27 18   52 42 43
   ........................... shortened .............................
   - 72  0  0    35 50 18    0 18 21    37   -28   36 16 44   35 23 57
   - 74  0  0    34 42 15    0 18 30    35   -27   35  8 50   34 15 46
   - 76  0  0    33 32 11    0 18 40    33   -25   33 58 53   33  5 34
   - 78  0  0    32 20  9    0 18 48    31   -23   32 46 57   31 53 25
   - 80  0  0    31  6 15    0 18 57    29   -21   31 33  9   30 39 25
   - 82  0  0    29 50 35    0 19  5    27   -19   30 17 35   29 23 40
   - 84  0  0    28 33 16    0 19 13    25   -17   29  0 20   28  6 17
   - 86  0  0    27 14 26    0 19 20    23   -15   27 41 34   26 47 24
   - 88  0  0    25 54 15    0 19 27    20   -13   26 21 25   25 27 10
   - 90  0  0    24 32 51    0 19 33    18   -11   25  0  3   24  5 45
   ........................... 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-|
--------------------------------------------------------------------U---U---