Update for (287) Nephthys - April 28/29, 2003

Jan Manek's update

                    IOTA/IOTA-ES occultation update for
           (287) Nephthys / TYC 1385-00019-1 = SAO 79969 on April 28/29, 2003
        visible from France, SW Switzerland, Italy, Albania, NE Greece and Turkey

Summary 

In the night of April 28/29, 2003 a bright 9.1 mag star TYC 1385-00019-1 = SAO 79969 will be occulted by a 70 km asteroid (287) Nephthys. This update is based on USNO/Flagstaff and TMO astrometry for the asteroid and recent UCAC star position.

The updated path shows ~2.5 path width north shift with time 0.8 minutes earlier compared to Edwin Goffin's nominal prediction.

Updated path runs over France from NW to SE ~21:30.4 UT, SW Switzerland ~21:30.6 UT, Italy from NW to SE ~21:30.7 UT, Albania ~21:31.2 UT, NE Greece ~21:31.3 UT and Turkey ~21:31.5 UT. Please check the path chart for details.

Compared to Steve Preston's update this one is ~1/4 path width south of his path, the difference originating mainly from new UCAC star position. Please pay attention to possible satellite of Nephthys (as mentioned by Jean Lecacheux) so observers up to ~500km from main body path should try to observe. On assumption that satellite's size is ~1/10 of main body, the duration will be very short; under 0.5 second. Video observations or CCD drift scans are highly desirable in this case.

Still one more update will be probably issued ~week before the event. But I don't expect any large shift from this update.Clear sky and good luck !!!

The event at one glimpse:
 * date and approx. UT time of event: April 28, 2003 @ 21:30 UT (Europe)
 * magnitude of target star: 9.1
 * magnitude drop [mag]: 3.9
 * estimated maximum duration [s]: 3.3
 * path description: given above
 * Goffin's original chart reference: A03_0431

The occultation path:
 * approximate ground width [km]: 90
 * uncertainty [path widths]: 0.9
 * uncertainty in time [s]: 3
 * map: below
 * remarks: Path uncertainties are given according to nominal star
    position errors and expected asteroid positional accuracy.

Data for the target star:
 * name: TYC 1385-00019-1 = SAO 79969 = PPM 98378
 * constellation: Cancer
 * J2000 position [h,m,s; o,',"]: 08h 08m 11.6596s; +20o 33' 45.764"
 * position source: recent UCAC position combined with Tycho-2 proper motion
 * estimated accuracy ["]: 0.03" (0.02", 0.02")
 * V mag [mag]: 9.05
 * B-V [mag]: +1.32
 * remarks:
    Recent UCAC position was provided by Marion and Norbert Zacharias.
    Target star is in east Cancer, about 8 degrres east of open cluster M44 or 1.0 degree south
    of 5.3 mag star mu2 Cancri = SAO 79959.
    !!! 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.

Close finding chart (prepared in GUIDE8):
 * occulted star is in center - labeled with cross
 * field is 3.0x3.0 degrees
 * limiting magnitude is 12.0
 * labeled stars have indicated SAO numbers
 * remarks: Second chart is 30' blowup to show correctly the target star in the field.











Data for the minor planet:
 * general information:
     number, name: (287) Nephthys
     approx. diameter [km]: 70
 * orbital information
     orbit source: calculation Manek
     source of used astrometry: USNO/Flagstaff (Ron Stone), TMO (Bill Owen)
     number of used observations: 110 USNO, 43 TMO
     number of rejected observations: 17 USNO, 8 TMO
     time covered by the observations: 1997 05 22 - 2003 03 26
     rms residuals ["] (RA,DE): 0.05", 0.05"
     estimated positional accuracy at epoch of event ["]: 0.03", 0.03"
     remarks:

Data for the event:
 * UT date and time of least geocentric approach: 21:27.6 UT
 * approx. V mag of minor planet at event [mag]: 13.0
 * geocentric parallax of minor planet ["]: 3.817
 * magnitude drop [mag]: 3.9
 * estimated maximum duration [s]: 3.3
 * apparent motion of minor planet ["/h]: 45.41
 * angular distance to moon, phase of moon [deg,%]: 110, 6%
 * remarks:

Elements for WinOccult:
============ cut here ===========================================
 2003 Apr 28
   287 Nephthys
21h 27.6m UT
   9.1    8  8 11.660 20 33 45.76TYC 1385-00019-1
13.0     70    3.3   2.304     3.228     -2.74
  -56.298  20.564  -142.53   14.24
 21.4605   .03469   .59686 11.88124 -0.71706  0.00534 -0.00115
2000    243.7415032003 421.00000118.644833142.49388010.023290 0.023559572.353769972.298316168.305   0.22
RATE 2.7293430 .0000000 .0000000 .0000000 .00000000 .00000000 .00000000
============ cut here ===========================================

Calculator(s): Jan Manek









Path coordinates:
                  Centre              Star  Star   Sun      Path Limits           Error Limits
  E. Longitude   Latitude      U.T.    Alt    Az   Alt    Limit 1    Limit 2    Limit 3    Limit 4
                                                         Latitude   Latitude   Latitude   Latitude
   ........................................ shortened ............................................
      o  '  "     o  '  "    h  m  s     o     o     o    o  '  "    o  '  "    o  '  "    o  '  "
   - 16  0  0    52 20 10   21 29 28    45   241    -9   51 55  1   52 45 28   51 10  5   53 31 23
   - 15  0  0    52  6 24   21 29 31    45   242   -10   51 41 12   52 31 45   50 56 11   53 17 47
   - 14  0  0    51 52 21   21 29 35    44   243   -11   51 27  6   52 17 45   50 41 59   53  3 52
   - 13  0  0    51 38  0   21 29 38    44   244   -11   51 12 42   52  3 28   50 27 30   52 49 40
   - 12  0  0    51 23 22   21 29 41    44   246   -12   50 58  0   51 48 52   50 12 43   52 35 11
   - 11  0  0    51  8 25   21 29 44    43   247   -13   50 43  1   51 33 59   49 57 38   52 20 24
   - 10  0  0    50 53 11   21 29 47    43   248   -13   50 27 44   51 18 48   49 42 16   52  5 19
   -  9  0  0    50 37 40   21 29 50    42   249   -14   50 12  9   51  3 20   49 26 36   51 49 56
   -  8  0  0    50 21 51   21 29 53    42   251   -14   49 56 17   50 47 34   49 10 39   51 34 16
   -  7  0  0    50  5 45   21 29 56    41   252   -15   49 40  8   50 31 31   48 54 24   51 18 18
   -  6  0  0    49 49 21   21 29 59    40   253   -16   49 23 41   50 15 10   48 37 52   51  2  3
   -  5  0  0    49 32 40   21 30  2    40   254   -16   49  6 57   49 58 32   48 21  3   50 45 30
   -  4  0  0    49 15 42   21 30  5    39   255   -17   48 49 56   49 41 37   48  3 57   50 28 40
   -  3  0  0    48 58 27   21 30  8    39   256   -18   48 32 38   49 24 24   47 46 34   50 11 33
   -  2  0  0    48 40 54   21 30 11    38   257   -18   48 15  3   49  6 55   47 28 55   49 54  9
   -  1  0  0    48 23  6   21 30 14    38   259   -19   47 57 12   48 49  9   47 10 58   49 36 28
      0  0  0    48  5  0   21 30 17    37   260   -20   47 39  4   48 31  6   46 52 46   49 18 30
      1  0  0    47 46 38   21 30 20    36   261   -20   47 20 40   48 12 47   46 34 17   49  0 15
      2  0  0    47 28  0   21 30 23    36   262   -21   47  1 59   47 54 11   46 15 32   48 41 45
      3  0  0    47  9  6   21 30 26    35   263   -22   46 43  3   47 35 20   45 56 32   48 22 58
      4  0  0    46 49 57   21 30 29    34   264   -22   46 23 51   47 16 12   45 37 16   48  3 54
      5  0  0    46 30 31   21 30 32    34   265   -23   46  4 23   46 56 50   45 17 44   47 44 36
      6  0  0    46 10 51   21 30 35    33   266   -24   45 44 41   46 37 11   44 57 58   47 25  1
      7  0  0    45 50 56   21 30 37    32   267   -24   45 24 43   46 17 18   44 37 57   47  5 12
      8  0  0    45 30 45   21 30 40    32   268   -25   45  4 31   45 57 10   44 17 41   46 45  7
      9  0  0    45 10 21   21 30 43    31   269   -26   44 44  5   45 36 47   43 57 12   46 24 48
     10  0  0    44 49 43   21 30 45    30   270   -26   44 23 25   45 16 10   43 36 29   46  4 15
     11  0  0    44 28 50   21 30 48    30   270   -27   44  2 31   44 55 20   43 15 32   45 43 27
     12  0  0    44  7 45   21 30 51    29   271   -28   43 41 24   44 34 16   42 54 23   45 22 26
     13  0  0    43 46 27   21 30 53    28   272   -28   43 20  4   44 12 59   42 33  1   45  1 12
     14  0  0    43 24 56   21 30 56    27   273   -29   42 58 32   43 51 30   42 11 26   44 39 45
     15  0  0    43  3 13   21 30 58    27   274   -29   42 36 48   43 29 48   41 49 40   44 18  6
     16  0  0    42 41 19   21 31  1    26   275   -30   42 14 53   43  7 55   41 27 43   43 56 14
     17  0  0    42 19 13   21 31  3    25   276   -31   41 52 46   42 45 50   41  5 35   43 34 11
     18  0  0    41 56 57   21 31  5    24   276   -31   41 30 29   42 23 35   40 43 16   43 11 57
     19  0  0    41 34 30   21 31  8    24   277   -32   41  8  2   42  1  9   40 20 48   42 49 33
     20  0  0    41 11 54   21 31 10    23   278   -33   40 45 25   41 38 33   39 58 10   42 26 58
     21  0  0    40 49  9   21 31 12    22   279   -33   40 22 40   41 15 48   39 35 24   42  4 14
     22  0  0    40 26 15   21 31 14    21   280   -34   39 59 45   40 52 54   39 12 29   41 41 21
     23  0  0    40  3 13   21 31 16    20   280   -34   39 36 43   40 29 52   38 49 27   41 18 19
     24  0  0    39 40  3   21 31 18    19   281   -35   39 13 33   40  6 43   38 26 17   40 55  9
     25  0  0    39 16 46   21 31 20    19   282   -36   38 50 17   39 43 26   38  3  1   40 31 53
     26  0  0    38 53 24   21 31 22    18   282   -36   38 26 54   39 20  3   37 39 39   40  8 29
     27  0  0    38 29 55   21 31 24    17   283   -37   38  3 26   38 56 34   37 16 11   39 44 59
     28  0  0    38  6 21   21 31 25    16   284   -37   37 39 53   38 33  0   36 52 38   39 21 24
     29  0  0    37 42 43   21 31 27    15   284   -38   37 16 15   38  9 21   36 29  2   38 57 44
     30  0  0    37 19  1   21 31 28    14   285   -38   36 52 34   37 45 38   36  5 22   38 34  0
     31  0  0    36 55 15   21 31 30    13   286   -39   36 28 49   37 21 52   35 41 39   38 10 12
     32  0  0    36 31 27   21 31 31    13   286   -39   36  5  2   36 58  3   35 17 53   37 46 21
     33  0  0    36  7 37   21 31 32    12   287   -40   35 41 13   36 34 12   34 54  6   37 22 28
     34  0  0    35 43 46   21 31 33    11   288   -40   35 17 23   36 10 19   34 30 19   36 58 33
     35  0  0    35 19 54   21 31 35    10   288   -41   34 53 33   35 46 26   34  6 30   36 34 37
     36  0  0    34 56  2   21 31 36     9   289   -41   34 29 42   35 22 32   33 42 43   36 10 41
     37  0  0    34 32 11   21 31 36     8   289   -41   34  5 53   34 58 40   33 18 56   35 46 46
     38  0  0    34  8 21   21 31 37     7   290   -42   33 42  4   34 34 48   32 55 10   35 22 51
     39  0  0    33 44 34   21 31 38     6   291   -42   33 18 19   34 10 59   32 31 28   34 58 58
     40  0  0    33 20 49   21 31 39     5   291   -42   32 54 35   33 47 12   32  7 48   34 35  8
     41  0  0    32 57  7   21 31 39     4   292   -43   32 30 56   33 23 28   31 44 12   34 11 21
   ........................................ 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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