Update for (248) Lameia - November 9/10, 1999

Jan Manek's update

                     IOTA/IOTA-ES occultation update for
        (248) Lameia / TYC 1260 00449 1 event on November 9/10, 1999
             visible from southern Spain and Portugal in Europe,
     South Carolina, Georgia, NW Florida, S Alabama, very SE Louisiana, 
               very SW Texas and north Mexico in North America


Summary 

In the night November 9/10, 1999 a 10.2 mag star TYC 1260 00449 1 will be occulted by a 52 km asteroid (248) Lameia. This update is based on USNO/Flagstaff astrometry for the asteroid and ACT star position.

The updated path runs ~1 path width south with time ~0.3 minutes later compared to Edwin Goffin's nominal prediction.

The path now runs over southern Spain and southern Portugal at ~5:26 UT. After crossing Atlantic Ocean path runs over South Carolina at ~5:33.5 UT, Georgia ~5:34 UT, NW Florida and S Alabama ~5:34.5 UT, very SE Louisiana at ~5:35, very SW Texas ~5:36 UT and north Mexico around 5:37 UT.

The uncertainity for this event is rather large, however occultation by (248) Lameia was successfully observed by 5 people in South Africa on June 27, 1998. Relative to this update it was observed about 0.6 path width north of this path, so maybe observers on the northern limit have slightly larger chance for this event.

Star is quite red, so drift scan observations with 8" telescope at focal length ~700 mm should be easy despite 10.2 magnitude, which is in V band. Don't forget to calibrate the scans in some way, so not only duration but also absolute times could be extracted from your images.

The event at one glimpse:
 * date and approx. UT time of event: November 10, 1999 @ 05:26 UT (Euro)
                                        05:34 UT (USA), 05:37 UT (Mexico)
 * magnitude of target star: 10.2
 * magnitude drop [mag]: 3.6
 * estimated maximum duration [s]: 4.4
 * path description: given above

The occultation path:
 * approximate ground width [km]: 55
 * uncertainty [path widths]: 3.5
 * uncertainty in time [s]: 20
 * map: 2 attached (1 for Europe, 1 for North America)
 * 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: TYC 1260 00449 1
 * constellation: Taurus
 * J2000 position [h,m,s; o,',"]: 03h 49m 41.669s; +21o 26' 06.41"
 * position source: ACT
 * estimated accuracy ["]: 0.08" (0.08", 0.03")
 * V mag [mag]: 10.24
 * B-V [mag]: +1.18
 * remarks: TYCHO gives quality flag 5 (=medium) together with 
     'no duplicity' flag.

     Target star is in western Taurus, about 3 degrees south of famous
     M45 open cluster. About 11' SW of target is 8.2 mag star SAO 76227
     and also be careful - there is 10.5 mag star TYC 1260 00315 only 
     1' just north of target.

Data for the minor planet:
 * general information:
     number, name: (248) Lameia
     approx. diameter [km]: 52
 * orbital information
     orbit source: calculation Manek
     source of used astrometry: USNO/Flagstaff (Ron Stone)
     number of used observations: 34 USNO
     number of rejected observations: 5 USNO
     time covered by the observations: 1998 05 25 - 1999 11 01
     rms residuals ["] (RA,DE): 0.10", 0.10"
     estimated positional accuracy at epoch of event ["]: 0.10"
     remarks: 

Data for the event:
 * UT date and time of least geocentric approach: 05:33:37 UT
 * approx. V mag of minor planet at event [mag]: 13.8
 * geocentric parallax of minor planet ["]: 5.359
 * magnitude drop [mag]: 3.6
 * estimated maximum duration [s]: 4.4
 * apparent motion of minor planet ["/h]: 35.67
 * angular distance to moon, phase of moon [deg,%]: 169, 4%
 * remarks: 

Calculator(s): Jan Manek








Path coordinates:
                                       Altitude
  E. Longitude    Latitude     U.T.    star  sun
   ........ shortened ..........................
   +  9 00 00   + 34 20 13    5 25 16   18    -6
   +  7 00 00   + 34 51 11    5 25 21   20    -8
   +  5 00 00   + 35 20 31    5 25 27   22    -9
   +  3 00 00   + 35 48 13    5 25 33   23   -11
   +  1 00 00   + 36 14 17    5 25 40   25   -13
   -  1 00 00   + 36 38 44    5 25 47   27   -14
   -  3 00 00   + 37 01 35    5 25 54   28   -16
   -  5 00 00   + 37 22 51    5 26 02   30   -18
   -  7 00 00   + 37 42 32    5 26 09   31   -19
   -  9 00 00   + 38 00 39    5 26 18   33   -21
   - 11 00 00   + 38 17 13    5 26 26   35   -22
   - 13 00 00   + 38 32 14    5 26 35   36   -24
   - 15 00 00   + 38 45 44    5 26 44   38   -25
   ........ shortened ..........................
   - 71 00 00   + 35 01 03    5 32 31   76   -67
   - 73 00 00   + 34 31 16    5 32 47   77   -68
   - 75 00 00   + 33 59 58    5 33 03   77   -70
   - 77 00 00   + 33 27 07    5 33 19   78   -71
   - 79 00 00   + 32 52 43    5 33 35   78   -72
   - 81 00 00   + 32 16 47    5 33 51   78   -74
   - 83 00 00   + 31 39 20    5 34 08   77   -75
   - 85 00 00   + 31 00 21    5 34 25   77   -76
   - 87 00 00   + 30 19 52    5 34 41   76   -77
   - 89 00 00   + 29 37 53    5 34 58   75   -77
   - 91 00 00   + 28 54 26    5 35 15   74   -78
   - 93 00 00   + 28 09 32    5 35 33   73   -78
   - 95 00 00   + 27 23 12    5 35 50   71   -78
   - 97 00 00   + 26 35 28    5 36 07   70   -77
   - 99 00 00   + 25 46 23    5 36 24   68   -77
   -101 00 00   + 24 55 59    5 36 41   66   -76
   -103 00 00   + 24 04 19    5 36 59   65   -74
   -105 00 00   + 23 11 25    5 37 16   63   -73
   -107 00 00   + 22 17 22    5 37 33   61   -72
   -109 00 00   + 21 22 12    5 37 50   59   -70
   -111 00 00   + 20 26 01    5 38 06   57   -68
   -113 00 00   + 19 28 51    5 38 23   55   -67
  ........ shortened ..........................

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Jan Manek
Stefanik Observatory                Private :
Petrin 205                          Werichova 950
118 46  Praha 1                     152 00  Praha 5 - Barrandov     |_|_|
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Internet : jmanek@mbox.vol.cz                                      |-O-O-|
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