Update for (1819) Laputa - March 24/25, 2002

Jan Manek's update

                    IOTA/IOTA-ES occultation update for
           (1819) Laputa / rho2 Cancri on March 24/25, 2002
     visible from Lybia, Tunisia, France, England, Ireland and Iceland


Summary 

In the night of March 24/25, 2002 a bright 5.2 mag star rho2 Cancri = FK6 2705 will be occulted by a small 45 km asteroid (1819) Laputa. This update is based on USNO/Flagstaff astrometry for the asteroid and combined FK6 star position.

The updated path shows ~3 path width west shift with time ~3.0 minutes earlier compared to Edwin Goffin's nominal prediction.

Updated path runs over Lybia ~23:57 UT, Tunisia with capital Tunis ~23:59 UT, France from south to northwest around 00:02.5 UT, west England around 00:04.5 UT, Ireland around 00:05.5 UT and Iceland ~00:10 UT. I'm not giving detailed description of path, because the overall uncertainty is rather large with 6.5 path widths. Within these limits is northeast Spain with Barcelona, whole France, whole U. K. and Ireland. Please check the path chart for details.

80% Moon is 7 degrees south of target, but as the star is bright this should be no complication to cover the 60 km wide path sufficiently. Star should be in reach even for some commercial camcorders setted for maximal zoom, without any telescope. Try in advance if your camera is capable of recording the star and time stamp the recording in some way. Keep in mind also time uncertainty so observe in interval at least plus minus 1 minute around the time of closest approch to your location. With such a bright star it is one of the best opportunities this year for Europe. Clear sky and good luck !!!

The event at one glimpse:
 * date and approx. UT time of event: March 25, 2002 @ 00:03 UT
 * magnitude of target star: 5.2
 * magnitude drop [mag]: 11.0
 * estimated maximum duration [s]: 8.2
 * path description: given above
 * Goffin's original chart reference: A02_0346

The occultation path:
 * approximate ground width [km]: 60
 * uncertainty [path widths]: 6.5
 * uncertainty in time [s]: 55
 * map: below
 * remarks: Path uncertainties are given according to nominal star
    position errors and expected asteroid positional accuracy.

Data for the target star:
 * name: rho2 Cancri = SAO 80511 = PPM 99160 = FK6 2705
 * constellation: Cancer
 * J2000 position [h,m,s; o,',"]: 08h 55m 39.678s; +27o 55' 38.87"
 * position source: FK6
 * estimated accuracy ["]: 0.01" (0.01", 0.01")
 * V mag [mag]: 5.23
 * B-V [mag]: +1.00
 * remarks:
    Target star is in north Cancer, about 9 degrees north of M44 (Beehive) cluster.

Close finding chart (prepared in GUIDE7):
 * occulted star is in center - labeled with cross
 * field is 18.0x18.0 degrees
 * limiting magnitude is 10.4
 * labeled stars have indicated SAO numbers
 * remarks:





Data for the minor planet:
 * general information:
     number, name: (1819) Laputa
     approx. diameter [km]: 45
 * orbital information
     orbit source: calculation Manek
     source of used astrometry: USNO/Flagstaff (Ron Stone)
     number of used observations: 70 USNO
     number of rejected observations: 5 USNO
     time covered by the observations: 1998 08 02 - 2002 03 15
     rms residuals ["] (RA,DE): 0.13", 0.13"
     estimated positional accuracy at epoch of event ["]: 0.12", 0.12"
     remarks:

Data for the event:
 * UT date and time of least geocentric approach: 00:06.6 UT
 * approx. V mag of minor planet at event [mag]: 16.2
 * geocentric parallax of minor planet ["]: 2.922
 * magnitude drop [mag]: 11.0
 * estimated maximum duration [s]: 8.2
 * apparent motion of minor planet ["/h]: 9.07
 * angular distance to moon, phase of moon [deg,%]: 7, 80%
 * remarks:

Calculator(s): Jan Manek








Path coordinates:
                                                   Latitude   Latitude
                  Center               Altitude       Path Limits
  E. Longitude   Latitude      U.T.   star   sun   Limit 1    Limit 2
   ........................... shortened .............................
      o  '  "     o  '  "    h  m  s     o     o    o  '  "    o  '  "
     23  0  0    23 44 14   23 54 58    28   -58   24  6 28   23 22 10
     22  0  0    24 40  8   23 55 14    29   -58   25  2 38   24 17 49
     21  0  0    25 36 50   23 55 30    30   -58   25 59 35   25 14 16
     20  0  0    26 34 18   23 55 47    31   -57   26 57 19   26 11 27
     19  0  0    27 32 29   23 56 05    32   -57   27 55 48   27  9 23
     18  0  0    28 31 24   23 56 23    33   -56   28 54 59   28  8  0
     17  0  0    29 30 58   23 56 42    34   -56   29 54 52   29  7 17
     16  0  0    30 31 11   23 57 01    35   -55   30 55 23   30  7 13
     15  0  0    31 32  0   23 57 21    36   -55   31 56 30   31  7 44
     14  0  0    32 33 23   23 57 42    37   -54   32 58 12   32  8 48
     13  0  0    33 35 18   23 58 03    38   -53   34  0 26   33 10 24
     12  0  0    34 37 41   23 58 24    39   -53   35  3 10   34 12 29
     11  0  0    35 40 31   23 58 46    40   -52   36  6 20   35 14 59
     10  0  0    36 43 44   23 59  8    41   -51   37  9 54   36 17 53
      9  0  0    37 47 18   23 59 30    42   -50   38 13 48   37 21  6
      8  0  0    38 51 10   23 59 53    42   -49   39 18  1   38 24 37
      7  0  0    39 55 15    0  0 16    43   -48   40 22 28   39 28 22
      6  0  0    40 59 32    0  0 40    44   -47   41 27  7   40 32 18
      5  0  0    42  3 56    0  1  3    45   -46   42 31 53   41 36 21
      4  0  0    43  8 24    0  1 27    45   -45   43 36 43   42 40 27
      3  0  0    44 12 52    0  1 51    46   -44   44 41 33   43 44 33
      2  0  0    45 17 15    0  2 15    46   -43   45 46 20   44 48 36
      1  0  0    46 21 31    0  2 39    47   -42   46 50 58   45 52 30
      0  0  0    47 25 35    0  3  3    47   -41   47 55 24   46 56 12
   -  1  0  0    48 29 22    0  3 27    48   -40   48 59 34   47 59 39
   -  2  0  0    49 32 49    0  3 51    48   -39   50  3 22   49  2 44
   -  3  0  0    50 35 50    0  4 15    48   -38   51  6 45   50  5 25
   -  4  0  0    51 38 22    0  4 39    49   -37   52  9 38   51  7 37
   -  5  0  0    52 40 19    0  5  3    49   -36   53 11 55   52  9 14
   -  6  0  0    53 41 37    0  5 26    49   -35   54 13 33   53 10 14
   -  7  0  0    54 42 12    0  5 49    49   -33   55 14 27   54 10 31
   -  8  0  0    55 41 58    0  6 12    49   -32   56 14 31   55 10  1
   -  9  0  0    56 40 52    0  6 34    49   -31   57 13 42   56  8 39
   - 10  0  0    57 38 50    0  6 56    49   -30   58 11 54   57  6 22
   - 11  0  0    58 35 46    0  7 17    49   -29   59  9  4   58  3  5
   - 12  0  0    59 31 37    0  7 39    49   -28   60  5  7   58 58 45
   - 13  0  0    60 26 19    0  7 59    49   -27   60 59 60   59 53 17
   - 14  0  0    61 19 49    0  8 19    49   -26   61 53 38   60 46 39
   - 15  0  0    62 12  2    0  8 39    48   -25   62 45 59   61 38 46
   - 16  0  0    63  2 58    0  8 58    48   -24   63 36 59   62 29 37
   - 17  0  0    63 52 32    0  9 16    48   -23   64 26 35   63 19  9
   - 18  0  0    64 40 43    0  9 34    48   -23   65 14 47   64  7 19
   - 19  0  0    65 27 29    0  9 51    47   -22   66  1 31   64 54  7
   - 20  0  0    66 12 48    0 10  8    47   -21   66 46 46   65 39 30
   - 21  0  0    66 56 40    0 10 24    47   -20   67 30 33   66 23 27
   - 22  0  0    67 39  4    0 10 39    47   -19   68 12 49   67  5 59
   - 23  0  0    68 19 60    0 10 54    46   -18   68 53 35   67 47  4
   - 24  0  0    68 59 28    0 11  9    46   -18   69 32 51   68 26 43
   - 25  0  0    69 37 29    0 11 22    46   -17   70 10 39   69  4 57
   - 26  0  0    70 14  4    0 11 36    45   -16   70 46 58   69 41 46
   - 27  0  0    70 49 13    0 11 48    45   -16   71 21 51   70 17 11
   - 28  0  0    71 22 60    0 12  0    45   -15   71 55 20   70 51 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 : jan.manek@worldonline.cz                                |-O-O-|
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