Update for (313) Chaldaea - October 25, 1998

Jan Manek's update

                     IOTA/IOTA-ES occultation update for
           (313) Chaldaea / TAC +07 02021 event on 1998 October 25
                           visible from Russia

Summary 

The event at one glimpse:
 * date and approx. UT time of event: October, 25, 1998 @ 2:43 UT.
 * magnitude of target star: 10.8
 * magnitude drop [mag]: 2.0
 * estimated maximum duration [s]: 10.2
 * path description: Path moves almost over north pole, hits eastern tip of
   Kola peninsula at ~2:41:30 and goes to south. Around 2:43 moves over Kazan
   and slightly later moves over Kuybyshev. For more eastern part of path the
   twilight will make problems.

The occultation path:
 * approximate width [km]: 120
 * uncertainty [path widths]: 1.5
 * map: attached
 * remarks: 

Data for the target star:
 * name: TAC +07 02021 = GSC 0145.0643
 * constellation: Monoceros
 * J2000 position [h,m,s; o,',"]: 06h 27m 26.076s; +07o 28' 58.34"
 * position source: USNO/Flagstaff
 * estimated accuracy ["]: 0.02"
 * V mag [mag]: 10.8
 * remarks:  8 degrees east of Betelgeuse (alpha Ori)

Data for the minor planet:
 * general information:
     mumber, name: (313) Chaldaea
     approx. diameter [km]: 101
 * orbital information
     orbit source: calculation Manek 
     source of used astrometry: USNO/Flagstaff (Ron Stone), TMO (Bill Owen), CAMC
     number of used observations: 6 USNO, 4 TMO, 24 CAMC
     number of rejected observations: 0
     time covered by the observations: 1996 2 13 - 1998 10 19
     rms residuals ["] (RA,DE): 0.18", 0.12"
     estimated positional accuracy at epoch of event ["]: 0.08"
     remarks:

Data for the event:
 * UT date and time of least geocentric approach: 02:46:36 UT
 * uncertainty in time [s]: 15
 * approx. V mag of minor planet at event [mag]: 12.6
 * geocentric parallax of minor planet ["]: 5.81
 * magnitude drop [mag]: 2.0
 * estimated maximum duration [s]: 10.2
 * apparent motion of minor planet ["/h]: 32.47
 * angular distance to moon, phase of moon [deg,%]: 161, 18%
 * remarks:

Calculator(s): Manek





Path coordinates:
                                       Altitude
  E. Longitude    Latitude     U.T.    star  sun
   + 19 00 00   + 85 42 50    2 39 40   12   -14
   + 21 00 00   + 85 11 29    2 39 42   12   -14
   + 23 00 00   + 84 32 49    2 39 45   13   -14
   + 25 00 00   + 83 44 49    2 39 48   14   -14
   + 27 00 00   + 82 45 00    2 39 52   15   -14
   + 29 00 00   + 81 30 43    2 39 58   16   -14
   + 31 00 00   + 79 59 35    2 40 05   17   -14
   + 33 00 00   + 78 10 06    2 40 15   19   -14
   + 35 00 00   + 76 02 16    2 40 27   21   -14
   + 37 00 00   + 73 37 39    2 40 43   23   -14
   + 39 00 00   + 70 59 01    2 41 01   26   -14
   + 41 00 00   + 68 09 34    2 41 23   28   -13
   + 43 00 00   + 65 12 32    2 41 48   31   -12
   + 45 00 00   + 62 10 46    2 42 16   33   -11
   + 47 00 00   + 59 06 44    2 42 46   35    -9
   + 49 00 00   + 56 02 29    2 43 18   37    -8
   + 51 00 00   + 52 59 41    2 43 51   39    -6
   + 53 00 00   + 49 59 43    2 44 26   40    -4

----------------------------------------------------------------------------
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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