Update for (41) Daphne - May 31, 1999

Jan Manek's update

                      IOTA/IOTA-ES occultation update for
                (41) Daphne / HIP 81189 event on 1999, May 31
                      visible from Russia and Khazachtan


Summary 

On the night May 31, 1999 will be occulted 8.2 mag star by a 182 km asteroid (41) Daphne. This update is based on USNO/Flagstaff and TMO astrometry for asteroid and HIPPARCOS star position.

This update gives ~1 path south shift and no time correction compared to Goffin's nominal prediction.

Path runs over middle-north part of European Russia, just north of Kazan ~22:11 UT and over Khazachstan. However the conditions will be poor as at best the Sun will only 10 degrees below horizont and nearly full Moon is 33 degrees distant.

The event at one glimpse:
 * date and approx. UT time of event: May 31, 1999 @ 22:10 UT
 * magnitude of target star: 8.2
 * magnitude drop [mag]: 1.7
 * estimated maximum duration [s]: 29.5
 * path description: Path runs over middle-north part of European Russia, just
     north of Kazan ~22:11 UT and over Khazachstan. However the conditions will 
     be poor as at best the Sun will only 8-10 degrees below horizont.
     Check the chart for details.

The occultation path:
 * approximate width [km]: 310
 * uncertainty [path widths]: 0.4
 * uncertainty in time [s]: 10
 * map: see below
 * 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: HIP 81189 = SAO 121709 = PPM 162824 = TYC 0394 00225 1
 * constellation: Hercules
 * J2000 position [h,m,s; o,',"]: 16h 35m 01.626s; +06o 50' 58.08"
 * position source: HIPPARCOS
 * estimated accuracy ["]: 0.01"  (0.01", 0.01")
 * Johnson V mag [mag]: 8.22
 * B-V [mag]: +0.18
 * remarks: 
     Target star is in very south-west Hercules, 5 degrees north of 3.9 mag star 
     lambda Oph or 6 degrees SW of 3.2 mag star kappa Oph. 31' NE of target is
     7.3 mag star Y Her = SAO 121728 and 34' in the opposite direction a pair of 
     stars, the brighter 7.6 mag one being SAO 121685.
     Be sure to have enough time for finding the correct star.

Data for the minor planet:
 * general information:
     number, name: (41) Daphne
     approx. diameter [km]: 182
 * orbital information
     orbit source: calculation Manek
     source of used astrometry: USNO/Flagstaff (Ron Stone), TMO (Bill Owen)
     number of used observations: 33 USNO, 21 TMO
     number of rejected observations: 2 USNO (1999 03 24.49754,1999 02 11.56979)
                                      1 TMO (1998 12 13.57095)
     time covered by the observations: 1998 02 12 - 1999 05 20
     rms residuals ["] (RA,DE): 0.08", 0.08"
     estimated positional accuracy at epoch of event ["]: 0.08"
     remarks: 

Data for the event:
 * UT date and time of least geocentric approach: 22:10:10 UT
 * approx. V mag of minor planet at event [mag]: 9.7
 * geocentric parallax of minor planet ["]: 8.031
 * magnitude drop [mag]: 1.7
 * estimated maximum duration [s]: 29.5
 * apparent motion of minor planet ["/h]: 27.99
 * angular distance to moon, phase of moon [deg,%]: 33, 98%
 * remarks: 

Calculator(s): Jan Manek





Path coordinates:
                                       Altitude
  E. Longitude    Latitude     U.T.    star  sun
   ......... shortened .........................
   + 89 00 00   + 42 33 21   22 03 34   26    -5
   + 87 00 00   + 43 17 46   22 03 56   28    -6
   + 85 00 00   + 44 03 13   22 04 19   29    -6
   + 83 00 00   + 44 49 35   22 04 43   30    -7
   + 81 00 00   + 45 36 47   22 05 07   31    -7
   + 79 00 00   + 46 24 45   22 05 31   31    -8
   + 77 00 00   + 47 13 22   22 05 56   32    -8
   + 75 00 00   + 48 02 32   22 06 21   33    -8
   + 73 00 00   + 48 52 11   22 06 46   34    -9
   + 71 00 00   + 49 42 11   22 07 12   34    -9
   + 69 00 00   + 50 32 27   22 07 37   35    -9
   + 67 00 00   + 51 22 53   22 08 03   35    -9
   + 65 00 00   + 52 13 22   22 08 29   35    -9
   + 63 00 00   + 53 03 48   22 08 54   36    -9
   + 61 00 00   + 53 54 06   22 09 19   36    -9
   + 59 00 00   + 54 44 08   22 09 44   36    -9
   + 57 00 00   + 55 33 50   22 10 09   36    -9
   + 55 00 00   + 56 23 04   22 10 33   36    -8
   + 53 00 00   + 57 11 45   22 10 57   36    -8
   + 51 00 00   + 57 59 48   22 11 20   36    -8
   + 49 00 00   + 58 47 07   22 11 43   35    -7
   + 47 00 00   + 59 33 38   22 12 05   35    -7
   + 45 00 00   + 60 19 15   22 12 27   35    -6
   + 43 00 00   + 61 03 55   22 12 48   34    -6
   + 41 00 00   + 61 47 33   22 13 08   34    -6
   + 39 00 00   + 62 30 06   22 13 28   34    -5
   + 37 00 00   + 63 11 31   22 13 46   33    -5
   ......... 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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