Update for (987) Wallia - April 23/24, 2004

  • Update computed by Jan Manek;   issued 18 Apr 2004 20:14 +0200 (CEST)

  • Jan Manek's update

                         IOTA/IOTA-ES occultation update for
           (987) Wallia / TYC 6119-00572-1 = PPM 261404 on April 23/24, 2004
        visible from Middle East, Crete, S Italy, France, SW England and Ireland
    
    Summary 

    In the night of April 23/24, 2004 a bright 9.9 mag star TYC 6119-00572-1 = PPM 261404 will be occulted by a 45 km asteroid (987) Wallia. This update is based on USNO/Flagstaff and OAC astrometry for the asteroid and UCAC2 star position.

    The updated path shows ~3.5 path width north shift with time ~0.6 minutes earlier compared to Eric Frappa's nominal prediction.

    Updated path runs over Middle East ~23:21 UT, Crete ~23:22.7 UT, S Italy ~23:23.7 UT, France from SE to NW around 23:25.1 UT, SW England ~23:25.7 UT and Ireland ~23:26.0 UT. Please check the path chart for details.

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    Clear sky and good luck !!!

    The event at one glimpse:
     * date and approx. UT time of event: April 23, 2004 @ 23:25 UT (Europe)
     * magnitude of target star: 9.9
     * magnitude drop [mag]: 4.9
     * estimated maximum duration [s]: 3.0
     * approx. V mag of minor planet at event [mag]: 14.8
     * geocentric parallax of minor planet ["]: 3.472
     * apparent motion of minor planet ["/h]: 29.02
     * angular distance to moon, phase of moon [deg,%]: 122, 17%
     * Goffin's original chart reference: A04_XXXX
    
    The occultation path with path maps:
     * approximate ground width [km]: 100
     * uncertainty [path widths]: 2.3
     * uncertainty in time [s]: 15
     * map: Overview
            European part
     * remarks: Path uncertainties [2 sigmas] are given according to nominal star
                position errors and expected asteroid positional accuracy.
    
    Elements for WinOccult - use 'Save as ...' to download and save these elements.
    
    Finding charts (prepared in GUIDE8):
     * occulted star is in center - labeled with cross
     * labeled stars have indicated SAO numbers
     * (smaller) square box shows 30' field in all wider field charts
     * (larger) square box shows 3° field in wide field charts
     * remarks:
       Target star is in south Virgo, about 9.2 degrees SSW of 1.0 mag star alpha Virginis = SAO 157923 = Spica
       or 3.3 degrees NNW of 3.0 mag star gamma Hydrae = SAO 181543. Should be easy to find due to pair of
       5-mag stars SAO 157806 and 157823 close to target.
       !!! IMPORTANT !!!
       Purple stars in identification chart are so called 'non-star' objects in GSC; in dense fields
       the 'non-stars' are often real stars or blends of close pairs. Be careful about this.
       40-degree chart
       3-degree chart
       0.5-degree chart
    
    Data for the target star:
     * name: TYC 6119-00572-1 = PPM 261404
     * constellation: Virgo
     * J2000 position [h,m,s; o,',"]: 13h 15m 17.5285s; -20o 03' 29.925"
     * position source: UCAC2
     * estimated accuracy ["]: 0.03" (0.02", 0.02")
     * V mag [mag]: 9.93
     * B-V [mag]: +1.21
     * remarks:
    
    Data for the minor planet:
     * general information:
         number, name: (987) Wallia
         approx. diameter [km]: 45
     * orbital information
         orbit source: calculation Manek
         source of used astrometry: USNO/Flagstaff (Ron Stone), OAC (A.Lopez, R.Pacheco, J.Forteza)
         number of used observations: 126 USNO, 4 OAC
         number of rejected observations: 0
         time covered by the observations: 1998 03 02 - 2004 04 13
         rms residuals ["] (RA,DE): 0.15", 0.15"
         estimated positional accuracy at epoch of event ["]: 0.11", 0.05"
         remarks:
    
    Path coordinates: click here
    
    Calculator(s): Jan Manek
    
    ----------------------------------------------------------------------------
    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 AT worldonline.cz                             |-O-O-|
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