Update for (539) Pamina - August 16/17, 1999

Jan Manek's update

                    IOTA/IOTA-ES occultation update for
          (539) Pamina / SAO 162141 event on 1999, August 16/17
             visible from Italy, Spain, Portugal in Europe and
                    Nova Scotia, Maine in North America


Summary 

On the night August 16/17, 1999 will be occulted 8.9 mag star SAO 162141 by a small 55 km asteroid (539) Pamina. This update is based on USNO/Flagstaff and TMO astrometry for asteroid and ACT/TRC star position.

This update shows 4 path width south shift and time ~0.8 minutes earlier compared to Goffin's nominal prediction.

Path runs over mid-north Italy and Corse ~00:13.5 UT and then over Spain. Barcelona is just north of path at 00:15 UT and Madrid ~00:16 UT. Middle Portugal with Lisbon is close to path at ~00:17 UT. After crossing Atlantic ocean New Scotia is in path at ~00:31 UT and middle Maine at ~00:32 UT. Path runs to west, north of Montreal but probably twilight will prevent finding the star in time. Keep in mind the 2 path width uncertainity.

The event at one glimpse:
 * date and approx. UT time of event: August 17, 1999 @ 00:15 UT (Europe)
                                                        00:32 UT (N America)
 * magnitude of target star: 8.9
 * magnitude drop [mag]: 4.6
 * estimated maximum duration [s]: 11.0
 * path description: Path runs over mid-north Italy and Corse ~00:13.5 UT and
     then over Spain. Barcelona is just north of path at 00:15 UT and Madrid
     ~00:16 UT. Middle Portugal with Lisbon is close to path at ~00:17 UT.
     After crossing Atlantic ocean New Scotia is in path at ~00:31 UT and middle
     Maine at ~00:32 UT. Path runs to west, north of Montreal but probably
     twilight will prevent finding the star in time. Keep in mind the 2 path
     width uncertainity.

The occultation path:
 * approximate width [km]: 100
 * uncertainty [path widths]: 2
 * uncertainty in time [s]: 25
 * map: attached
 * remarks: Path uncertainities are given according to nominal star position
    errors and expected asteroid positional accuracy.
    !!!!!!!
    Circles along the path are OCCULT exactly calculated centerline points.
    !!!!!!!

Data for the target star:
 * name: SAO 162141 = PPM 235431 = TYC 6286 01107 1
 * constellation: Sagittarius
 * J2000 position [h,m,s; o,',"]: 19h 03m 24.927s; -18o 04' 05.33"
 * position source: TRC1.0
 * estimated accuracy ["]: 0.02"  (0.02", 0.02")
 * Johnson V mag [mag]: 8.89
 * B-V [mag]: +0.27
 * remarks: TYCHO gives quality flag 3 (high) together with 'no duplicity' flag.
     ACT and TRC1.0 give the same position.

     Target star is 3.3 degrees NW of 2.9 mag star pi Sagittarii. Due to field
     in Milky Way, have enough time to locate the correct star.

Data for the minor planet:
 * general information:
     number, name: (539) Pamina
     approx. diameter [km]: 55
 * orbital information
     orbit source: calculation Manek
     source of used astrometry: USNO/Flagstaff (Ron Stone), TMO (Bill Owen)
     number of used observations: 43 USNO, 5 TMO
     number of rejected observations: 3 USNO
            (1998 03 10.426856, 1998 04 10.328427, 1998 05 11.226689)
     time covered by the observations: 1998 02 26 - 1999 08 08
     rms residuals ["] (RA,DE): 0.10", 0.09"
     estimated positional accuracy at epoch of event ["]: 0.09"
     remarks:

Data for the event:
 * UT date and time of least geocentric approach: 00:24:06
 * approx. V mag of minor planet at event [mag]: 13.5
 * geocentric parallax of minor planet ["]: 5.569
 * magnitude drop [mag]: 4.6
 * estimated maximum duration [s]: 11.0
 * apparent motion of minor planet ["/h]: 15.78
 * angular distance to moon, phase of moon [deg,%]: 75, 30%
 * remarks:

Calculator(s): Jan Manek








Path coordinates:
                                       Altitude
  E. Longitude    Latitude     U.T.    star  sun
   + 22 00 00   + 45 52 31    0 12 46    4   -27
   + 20 00 00   + 45 14 25    0 12 51    5   -28
   + 18 00 00   + 44 37 46    0 12 58    7   -29
   + 16 00 00   + 44 02 38    0 13 06    8   -30
   + 14 00 00   + 43 29 03    0 13 16   10   -31
   + 12 00 00   + 42 57 04    0 13 27   11   -32
   + 10 00 00   + 42 26 43    0 13 40   13   -33
   +  8 00 00   + 41 58 02    0 13 54   14   -34
   +  6 00 00   + 41 31 02    0 14 10   15   -34
   +  4 00 00   + 41 05 44    0 14 27   17   -35
   +  2 00 00   + 40 42 10    0 14 46   18   -36
   +  0 00 00   + 40 20 21    0 15 06   19   -36
   -  2 00 00   + 40 00 18    0 15 27   21   -37
   -  4 00 00   + 39 42 00    0 15 49   22   -37
   -  6 00 00   + 39 25 30    0 16 13   23   -37
   -  8 00 00   + 39 10 46    0 16 37   24   -37
   - 10 00 00   + 38 57 49    0 17 02   25   -37
   - 12 00 00   + 38 46 39    0 17 29   26   -37
   - 14 00 00   + 38 37 17    0 17 56   27   -37
   - 16 00 00   + 38 29 43    0 18 24   28   -37
   ......... shortened .........................
   - 56 00 00   + 42 04 10    0 28 50   29   -18
   - 58 00 00   + 42 32 15    0 29 19   29   -17
   - 60 00 00   + 43 01 50    0 29 48   28   -15
   - 62 00 00   + 43 32 53    0 30 15   27   -14
   - 64 00 00   + 44 05 23    0 30 42   26   -12
   - 66 00 00   + 44 39 17    0 31 08   25   -11
   - 68 00 00   + 45 14 31    0 31 33   24    -9
   - 70 00 00   + 45 51 04    0 31 57   23    -8
   - 72 00 00   + 46 28 52    0 32 20   22    -7
   - 74 00 00   + 47 07 52    0 32 42   21    -5
   - 76 00 00   + 47 48 01    0 33 02   19    -4
   - 78 00 00   + 48 29 14    0 33 22   18    -2
   ......... shortened .........................

----------------------------------------------------------------------------
Jan Manek
Stefanik Observatory                Private :
Petrin 205                          Werichova 950
118 46  Praha 1                     152 00  Praha 5 - Barrandov     |_|_|
Czech Republic                      Czech Republic                  /   \
Internet : jmanek@mbox.vol.cz                                      |-O-O-|
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