Update for (760) Massinga - February 15, 2000

Jan Manek's update

                  IOTA/IOTA-ES occultation update for
         (760) Massinga / SAO 58191 event on February 15, 2000
      visible from N Ireland, SW England, France and South Africa


Summary 

In the evening of February 15, 2000 a 8.3 mag star TYC 2412-00074-1 = = SAO 58191 will be occulted by a 75 km asteroid (760) Massinga. This update is based on USNO/Flagstaff and TMO astrometry for the asteroid and Tycho-2 star position.

The updated path shows large ~0.8" east shift with time ~1.6 minutes earlier compared to Edwin Goffin's nominal prediction.

The path of this occultation runs over NE Ireland ~18:36 UT, SW England ~18:37 UT and France from NW to SE at ~18:38-40 UT. After that path runs over whole Africa and around 18:56 UT path runs over South Africa.

The event at one glimpse:
 * date and approx. UT time of event: February 15, 2000 @ 18:38 UT (Euro)
                                                          18:56 UT (S.Af.)
 * magnitude of target star: 8.3
 * magnitude drop [mag]: 4.5
 * estimated maximum duration [s]: 10.6
 * path description: given above
 * Goffin's original chart reference: A00_0224(.PS.GZ).

The occultation path:
 * approximate ground width [km]: 75
 * uncertainty [path widths]: 2.0
 * uncertainty in time [s]: 25
 * map: 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: SAO 58191 = PPM 70548 = TYC 2412-00074-1
 * constellation: Auriga
 * J2000 position [h,m,s; o,',"]: 05h 34m 26.637s; +35o 24' 46.36"
 * position source: Tycho-2
 * estimated accuracy ["]: 0.02" (0.01", 0.02")
 * V mag [mag]: 8.29
 * B-V [mag]: +1.39
 * remarks: 
     Target star is rather red and it is in southern Auriga with open 
     cluster M38 about 1.2 degrees NW and M36 ~1.3 degrees south of
     target star. There is 6.3 mag star SAO 58182 ~42' SSW of target.

Close finding chart (prepared in GUIDE7):
 * occulted star is in center - labeled with cross
 * field is 2.5x2.5 degrees
 * limiting magnitude is 11.5
 * labeled stars have indicated SAO numbers





Data for the minor planet:
 * general information:
     number, name: (760) Massinga
     approx. diameter [km]: 75
 * orbital information
     orbit source: calculation Manek
     source of used astrometry: USNO/Flagstaff (Ron Stone), TMO (Bill Owen)
     number of used observations: 57 USNO, 9 TMO
     number of rejected observations: 3 USNO, 2 TMO
     time covered by the observations: 1998 08 17 - 2000 02 07
     rms residuals ["] (RA,DE): 0.08", 0.07"
     estimated positional accuracy at epoch of event ["]: 0.08"
     remarks: 

Data for the event:
 * UT date and time of least geocentric approach: 03:02:05 UT
 * approx. V mag of minor planet at event [mag]: 12.8
 * geocentric parallax of minor planet ["]: 4.021
 * magnitude drop [mag]: 4.5
 * estimated maximum duration [s]: 10.6
 * apparent motion of minor planet ["/h]: 16.01
 * angular distance to moon, phase of moon [deg,%]: 17, 80%
 * remarks: 

Calculator(s): Jan Manek









Path coordinates:
                                       Altitude
  E. Longitude    Latitude     U.T.    star  sun
   ........ shortened ..........................
   - 11 00 00   + 57 36 59   18 35 17   60    -8
   -  9 00 00   + 56 18 56   18 35 41   61    -9
   -  7 00 00   + 54 51 39   18 36 07   63    -9
   -  5 00 00   + 53 13 38   18 36 37   65   -10
   -  3 00 00   + 51 23 05   18 37 10   67   -12
   -  1 00 00   + 49 17 40   18 37 47   70   -13
   +  1 00 00   + 46 54 31   18 38 29   72   -14
   +  3 00 00   + 44 09 57   18 39 17   75   -15
   +  5 00 00   + 40 59 12   18 40 13   78   -17
   +  7 00 00   + 37 16 09   18 41 17   80   -19
   +  9 00 00   + 32 52 48   18 42 32   82   -20
   + 11 00 00   + 27 38 58   18 44 00   80   -22
   + 13 00 00   + 21 22 17   18 45 44   75   -24
   + 15 00 00   + 13 50 03   18 47 43   68   -25
   + 17 00 00   +  4 55 08   18 49 54   59   -26
   + 19 00 00   -  5 11 55   18 52 08   49   -26
   + 21 00 00   - 15 52 44   18 54 09   38   -25
   + 23 00 00   - 26 12 09   18 55 40   28   -23
   + 25 00 00   - 35 26 38   18 56 39   19   -20
   + 27 00 00   - 43 18 13   18 57 11   11   -17
   + 29 00 00   - 49 48 10   18 57 24    4   -14
   ........ 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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