Update for (451) Patientia - June 10/11, 1999

Jan Manek's update

                      IOTA/IOTA-ES occultation update for
           (451) Patientia / PPM 733949 event on 1999, June 10/11
    possibly visible from southern Scotland, north England and Ireland


Summary 

On the night June 10/11, 1999 (that's tonight) will be occulted faint 10.4 mag star by a 230 km asteroid (451) Patientia. This update is based on USNO/Flagstaff and TMO astrometry for asteroid and ACT star position.

This update gives ~0.7 path width north shift and time ~0.5 minute earlier compared to Goffin's nominal prediction.

Currently the path is just grazing the Earth and no central line could be computed. North limit is off the globe while south limit runs along the coast of north Scotland in twiling and (North) Ireland. As the current uncertainity is 0.8 path widths, it is chance to observe the occultation from almost all Great Britain and Ireland, but very low altitude will complicate situation. Brightness drop is 1.4 mag but be aware of flickering (low altitude!) and the star is faint - I don't think there will be any success here.

The event at one glimpse:
 * date and approx. UT time of event: June 10, 1999 @ 23:58 UT
 * magnitude of target star: 10.4
 * magnitude drop [mag]: 1.4
 * estimated maximum duration [s]: 16.9
 * path description: Path runs over ocean, see text above.
     Check the attached chart for details.

The occultation path:
 * approximate width [km]: ---
 * uncertainty [path widths]: 0.8
 * uncertainty in time [s]: 15
 * 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: PPM 733949 = TYC 6844 01393 1
 * constellation: Sagittarius
 * J2000 position [h,m,s; o,',"]: 18h 23m 15.259s; -23o 44' 51.84"
 * position source: ACT
 * estimated accuracy ["]: 0.08"  (0.07", 0.05")
 * Johnson V mag [mag]: 10.36
 * B-V [mag]: +2.16
 * remarks: TYCHO quality flag is 5 (medium) with 'no duplicity flag' set.
     There is also flag indicating very uncertain magnitude. GSC gives 
     10.2 mag in ~V band. The B-V colour is uncertain. Star is not in TRC1.0.

     Target star is 2 degrees NW of 2.8 mag star lambda Sgr.

Data for the minor planet:
 * general information:
     number, name: (451) Patientia
     approx. diameter [km]: 230
 * orbital information
     orbit source: calculation Manek
     source of used astrometry: USNO/Flagstaff (Ron Stone), TMO (Bill Owen)
     number of used observations: 28 USNO, 14 TMO
     number of rejected observations: 0
     time covered by the observations: 1998 03 04 - 1999 05 31
     rms residuals ["] (RA,DE): 0.06", 0.07"
     estimated positional accuracy at epoch of event ["]: 0.07"
     remarks: 

Data for the event:
 * UT date and time of least geocentric approach: 23:58:47 UT
 * approx. V mag of minor planet at event [mag]: 11.4
 * geocentric parallax of minor planet ["]: 3.844
 * magnitude drop [mag]: 1.4
 * estimated maximum duration [s]: 16.9
 * apparent motion of minor planet ["/h]: 29.49
 * angular distance to moon, phase of moon [deg,%]: 122, 13%
 * remarks: 

Calculator(s): Jan Manek





Path coordinates:
                                       Altitude
  E. Longitude    Latitude     U.T.    star  sun
             not possible to calculate

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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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