Update for (738) Alagasta - April 10/11, 2003

Jan Manek's update

                    IOTA/IOTA-ES occultation update for
             (738) Alagasta / TYC 1359-01919-1 on April 10/11, 2003
  visible from Portugal, S Spain, N Algeria, Tunisia, N Libya and middle Egypt

Summary 

In the night of April 10/11, 2003 a faint 10.7 mag star TYC 1359-01919-1 will be occulted by a 65 km asteroid (738) Alagasta. This update is based on USNO/Flagstaff and TMO astrometry for the asteroid and recent UCAC star position.

The updated path shows ~4 path width south shift with time 0.2 minutes earlier compared to Edwin Goffin's nominal prediction.

Updated path runs over Portugal ~21:05.3 UT just north of Lisbon, S Spain ~21:05.6 UT, N Algeria ~21:06.3 UT, Tunisia ~21:06.6 UT, N Libya around 21:07.3 UT and middle Egypt around 21:08.0 UT. Please check the path chart for details.

Target star is in mid-east Gemini, about 1.0 degrees east of 3.5 mag star delta Geminorum = SAO 79294 and should be easy to find in spite of 59% Moon only 13 degrees east of star.Clear sky and good luck !!!

The event at one glimpse:
 * date and approx. UT time of event: April 10, 2003 @ 21:05 UT (Europe)
 * magnitude of target star: 10.7
 * magnitude drop [mag]: 4.9
 * estimated maximum duration [s]: 3.9
 * path description: given above
 * Goffin's original chart reference: A03_0455

The occultation path:
 * approximate ground width [km]: 70
 * uncertainty [path widths]: 1.2
 * uncertainty in time [s]: 6
 * 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 1359-01919-1
 * constellation: Gemini
 * J2000 position [h,m,s; o,',"]: 07h 24m 29.4647s; +21o 50' 55.451"
 * position source: recent UCAC position combined with Tycho-2 proper motion
 * estimated accuracy ["]: 0.02" (0.02", 0.01")
 * V mag [mag]: 10.70
 * B-V [mag]: +1.49
 * remarks:
    Target star is in mid-east Gemini, about 1.0 degrees east of 3.5 mag star delta Geminorum = SAO 79294
    and should be easy to find.
    !!! 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 12.5
 * 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: (738) Alagasta
     approx. diameter [km]: 65
 * orbital information
     orbit source: calculation Manek
     source of used astrometry: USNO/Flagstaff (Ron Stone), TMO (Bill Owen)
     number of used observations: 103 USNO, 24 TMO
     number of rejected observations: 20 USNO, 2 TMO
     time covered by the observations: 1998 02 14 - 2003 03 06
     rms residuals ["] (RA,DE): 0.06", 0.06"
     estimated positional accuracy at epoch of event ["]: 0.04", 0.04"
     remarks:

Data for the event:
 * UT date and time of least geocentric approach: 21:02.6 UT
 * approx. V mag of minor planet at event [mag]: 15.6
 * geocentric parallax of minor planet ["]: 3.220
 * magnitude drop [mag]: 4.9
 * estimated maximum duration [s]: 3.9
 * apparent motion of minor planet ["/h]: 30.13
 * angular distance to moon, phase of moon [deg,%]: 13, 59%
 * remarks:

Elements for WinOccult:
============ cut here ===========================================
 2003 Apr 10
738 Alagasta
21h  2.6m UT
59-01919-1  10.7    7 24 29.465 21 50 55.45TYC 1359-01919-1
15.6     65    3.9   2.731     2.159     -2.21
  -43.203  21.850  -135.31    8.04
 21.0430   .02727   .37632  9.33310 -0.68415  0.00569 -0.00083
2000    318.5905492003 4 1.0000041.923950 132.3875153.529230  0.063615363.036052212.8429126710.15   0.15
RATE 1.8631180 .0000000 .0000000 .0000000 .00000000 .00000000 .00000000
============ cut here ===========================================

Calculator(s): Jan Manek








Path coordinates:
                  Centre               Altitude       Path Limits
  E. Longitude   Latitude      U.T.   star   sun   Limit 1    Limit 2
                                                   Latitude   Latitude
  ............................. shortened ..................................
      o  '  "     o  '  "    h  m  s     o     o    o  '  "    o  '  "
   - 13  0  0    40  5 28   21  4 55    58   -19   39 45 42   40 25 17
   - 12  0  0    39 51 57   21  5  0    58   -20   39 32  8   40 11 48
   - 11  0  0    39 38  5   21  5  5    57   -20   39 18 15   39 57 59
   - 10  0  0    39 23 55   21  5 10    56   -21   39  4  2   39 43 50
   -  9  0  0    39  9 24   21  5 15    56   -22   38 49 30   39 29 22
   -  8  0  0    38 54 34   21  5 20    55   -23   38 34 37   39 14 33
   -  7  0  0    38 39 24   21  5 25    54   -24   38 19 25   38 59 26
   -  6  0  0    38 23 55   21  5 30    54   -24   38  3 54   38 43 59
   -  5  0  0    38  8  6   21  5 35    53   -25   37 48  3   38 28 12
   -  4  0  0    37 51 59   21  5 40    52   -26   37 31 53   38 12  7
   -  3  0  0    37 35 31   21  5 45    51   -27   37 15 24   37 55 42
   -  2  0  0    37 18 45   21  5 50    51   -28   36 58 36   37 38 58
   -  1  0  0    37  1 40   21  5 55    50   -29   36 41 29   37 21 55
      0  0  0    36 44 17   21  5 59    49   -29   36 24  3   37  4 33
      1  0  0    36 26 34   21  6  4    48   -30   36  6 18   36 46 53
      2  0  0    36  8 33   21  6  9    48   -31   35 48 16   36 28 54
      3  0  0    35 50 14   21  6 13    47   -32   35 29 54   36 10 37
      4  0  0    35 31 37   21  6 18    46   -33   35 11 15   35 52  2
      5  0  0    35 12 42   21  6 23    45   -33   34 52 18   35 33  9
      6  0  0    34 53 29   21  6 27    44   -34   34 33  4   35 13 58
      7  0  0    34 33 59   21  6 32    44   -35   34 13 32   34 54 30
      8  0  0    34 14 12   21  6 36    43   -36   33 53 43   34 34 45
      9  0  0    33 54  8   21  6 41    42   -37   33 33 37   34 14 43
     10  0  0    33 33 48   21  6 45    41   -38   33 13 15   33 54 24
     11  0  0    33 13 11   21  6 50    40   -38   32 52 36   33 33 49
     12  0  0    32 52 18   21  6 54    39   -39   32 31 42   33 12 58
     13  0  0    32 31 10   21  6 58    39   -40   32 10 32   32 51 51
     14  0  0    32  9 46   21  7  2    38   -41   31 49  7   32 30 29
     15  0  0    31 48  8   21  7  6    37   -42   31 27 27   32  8 53
     16  0  0    31 26 15   21  7 10    36   -43   31  5 33   31 47  1
     17  0  0    31  4  8   21  7 14    35   -43   30 43 24   31 24 56
     18  0  0    30 41 48   21  7 18    34   -44   30 21  2   31  2 36
     19  0  0    30 19 14   21  7 22    33   -45   29 58 27   30 40  4
     20  0  0    29 56 27   21  7 26    32   -46   29 35 40   30 17 19
     21  0  0    29 33 29   21  7 30    31   -47   29 12 40   29 54 21
     22  0  0    29 10 18   21  7 33    30   -48   28 49 28   29 31 11
     23  0  0    28 46 56   21  7 37    29   -48   28 26  5   29  7 50
     24  0  0    28 23 23   21  7 40    28   -49   28  2 31   28 44 18
     25  0  0    27 59 40   21  7 43    27   -50   27 38 47   28 20 36
     26  0  0    27 35 47   21  7 47    27   -51   27 14 54   27 56 44
     27  0  0    27 11 45   21  7 50    26   -51   26 50 51   27 32 43
     28  0  0    26 47 35   21  7 53    25   -52   26 26 40   27  8 33
     29  0  0    26 23 16   21  7 56    24   -53   26  2 21   26 44 14
     30  0  0    25 58 50   21  7 59    23   -54   25 37 54   26 19 49
     31  0  0    25 34 17   21  8  1    22   -54   25 13 21   25 55 16
     32  0  0    25  9 38   21  8  4    21   -55   24 48 42   25 30 37
     33  0  0    24 44 53   21  8  7    20   -56   24 23 57   25  5 52
     34  0  0    24 20  3   21  8  9    19   -56   23 59  7   24 41  3
     35  0  0    23 55  9   21  8 11    18   -57   23 34 12   24 16  8
     36  0  0    23 30 11   21  8 13    17   -58   23  9 15   23 51 10
     37  0  0    23  5 10   21  8 15    16   -58   22 44 14   23 26  9
     38  0  0    22 40  6   21  8 17    15   -59   22 19 11   23  1  5
     39  0  0    22 15  1   21  8 19    14   -60   21 54  6   22 35 60
     40  0  0    21 49 55   21  8 21    13   -60   21 28 60   22 10 53
     41  0  0    21 24 48   21  8 22    12   -61   21  3 54   21 45 46
     42  0  0    20 59 41   21  8 24    11   -61   20 38 48   21 20 38
     43  0  0    20 34 36   21  8 25    10   -61   20 13 43   20 55 32
  ............................. 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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