Update for (54) Alexandra - April 4/5, 2003

Jan Manek's update

                    IOTA/IOTA-ES occultation update for
             (54) Alexandra / TYC 1875-00830-1 on April 4/5, 2003
        visible from N Norway, N Sweden, SW Finland, Estonia and Russia

Summary 

In the evening of April 4/5, 2003 a faint 12.2 mag star TYC 1875-00830-1 will be occulted by a 171 km asteroid (54) Alexandra. This update is based on USNO/Flagstaff and TMO astrometry for the asteroid and recent UCAC star position.

The updated path shows ~1 path width SW shift with time 0.1 minutes earlier compared to Edwin Goffin's nominal prediction.

Updated path runs over N Norway ~19:45.2 UT, N Sweden ~19:45.3 UT, SW Finland around 19:45.7 UT with Helsinki in path and Turku on SW limit, Estonia ~19:45.9 UT and finally west Russia from NW to SE around 19:46.5 UT. Please check the path chart for details.

Clear sky and good luck !!!

The event at one glimpse:
 * date and approx. UT time of event: April 4, 2003 @ 19:46 UT (Europe)
 * magnitude of target star: 12.2
 * magnitude drop [mag]: 1.7
 * estimated maximum duration [s]: 7.8
 * path description: given above
 * Goffin's original chart reference: A03_0412

The occultation path:
 * approximate ground width [km]: 260
 * uncertainty [path widths]: 0.7
 * uncertainty in time [s]: 5
 * 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 1875-00830-1
 * constellation: Auriga
 * J2000 position [h,m,s; o,',"]: 05h 59m 43.0959s; +28o 32' 15.810"
 * position source: recent UCAC position combined with Tycho-2 proper motion
 * estimated accuracy ["]: 0.05" (0.03", 0.04")
 * V mag [mag]: 12.21
 * B-V [mag]: +1.31
 * remarks:
    Target star is in S Auriga, about 7.3 degrees east of 1.7 mag star beta Tauri = SAO 77168,
    on border with Taurus and close to border with Gemini.
    !!! 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: (54) Alexandra
     approx. diameter [km]: 171
 * orbital information
     orbit source: calculation Manek
     source of used astrometry: USNO/Flagstaff (Ron Stone), TMO (Bill Owen)
     number of used observations: 118 USNO, 10 TMO
     number of rejected observations: 17 USNO, 2 TMO
     time covered by the observations: 1998 11 14 - 2003 03 08
     rms residuals ["] (RA,DE): 0.06", 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: 19:44.3 UT
 * approx. V mag of minor planet at event [mag]: 13.7
 * geocentric parallax of minor planet ["]: 2.637
 * magnitude drop [mag]: 1.7
 * estimated maximum duration [s]: 7.8
 * apparent motion of minor planet ["/h]: 32.52
 * angular distance to moon, phase of moon [deg,%]: 43, 8%
 * remarks:

Elements for WinOccult:
============ cut here ===========================================
 2003 Apr 04
54 Alexandra
19h 44.3m UT
75-00830-1  12.2    5 59 43.096 28 32 15.81TYC 1875-00830-1
13.7    171    7.8   3.335     2.405     -7.29
  -38.871  28.540  -115.33    5.77
 19.7392   .16559   .72371 12.02083 -2.76662  0.00567  0.00014
2000    162.1515922003 4 1.00000345.068736313.52836011.828814 0.198237402.711178442.173721467.665   0.15
RATE 2.2078360 .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  '  "
      5  0  0    70 19 46   19 44 42    41    -4   68 40 55   72  3 23
      6  0  0    69 57 47   19 44 44    41    -5   68 18 14   71 42 14
      7  0  0    69 35  7   19 44 47    41    -5   67 54 51   71 20 22
      8  0  0    69 11 44   19 44 49    41    -6   67 30 47   70 57 46
      9  0  0    68 47 36   19 44 52    41    -6   67  6  0   70 34 25
     10  0  0    68 22 45   19 44 55    41    -7   66 40 30   70 10 18
     11  0  0    67 57  9   19 44 58    41    -7   66 14 16   69 45 25
     12  0  0    67 30 46   19 45  1    41    -8   65 47 19   69 19 44
     13  0  0    67  3 38   19 45  4    41    -9   65 19 36   68 53 15
     14  0  0    66 35 43   19 45  7    40    -9   64 51  9   68 25 57
     15  0  0    66  7  1   19 45 10    40   -10   64 21 58   67 57 50
     16  0  0    65 37 32   19 45 13    40   -10   63 52  1   67 28 54
     17  0  0    65  7 15   19 45 16    40   -11   63 21 19   66 59  7
     18  0  0    64 36 11   19 45 20    39   -12   62 49 52   66 28 30
     19  0  0    64  4 20   19 45 23    39   -12   62 17 40   65 57  4
     20  0  0    63 31 42   19 45 26    39   -13   61 44 44   65 24 47
     21  0  0    62 58 18   19 45 30    39   -14   61 11  5   64 51 40
     22  0  0    62 24  7   19 45 33    38   -15   60 36 42   64 17 44
     23  0  0    61 49 11   19 45 37    38   -15   60  1 36   63 42 59
     24  0  0    61 13 31   19 45 40    37   -16   59 25 49   63  7 27
     25  0  0    60 37  7   19 45 44    37   -17   58 49 21   62 31  7
     26  0  0    60  0  0   19 45 48    37   -18   58 12 14   61 54  1
     27  0  0    59 22 12   19 45 51    36   -19   57 34 28   61 16 11
     28  0  0    58 43 45   19 45 55    36   -19   56 56  6   60 37 37
     29  0  0    58  4 39   19 45 59    35   -20   56 17  9   59 58 22
     30  0  0    57 24 57   19 46  3    35   -21   55 37 38   59 18 27
     31  0  0    56 44 40   19 46  6    34   -22   54 57 35   58 37 54
     32  0  0    56  3 51   19 46 10    34   -23   54 17  2   57 56 45
     33  0  0    55 22 31   19 46 14    33   -24   53 36  1   57 15  2
     34  0  0    54 40 42   19 46 18    32   -25   52 54 35   56 32 48
     35  0  0    53 58 28   19 46 21    32   -26   52 12 44   55 50  4
     36  0  0    53 15 49   19 46 25    31   -26   51 30 32   55  6 54
     37  0  0    52 32 49   19 46 29    30   -27   50 48  1   54 23 20
     38  0  0    51 49 29   19 46 33    30   -28   50  5 13   53 39 25
     39  0  0    51  5 54   19 46 36    29   -29   49 22 10   52 55 11
     40  0  0    50 22  4   19 46 40    28   -30   48 38 55   52 10 40
     41  0  0    49 38  3   19 46 43    27   -31   47 55 31   51 25 57
     42  0  0    48 53 53   19 46 47    26   -32   47 11 59   50 41  3
     43  0  0    48  9 37   19 46 50    26   -33   46 28 22   49 56  1
     44  0  0    47 25 16   19 46 53    25   -34   45 44 42   49 10 54
     45  0  0    46 40 55   19 46 56    24   -35   45  1  3   48 25 44
     46  0  0    45 56 35   19 46 59    23   -36   44 17 26   47 40 35
     47  0  0    45 12 19   19 47  2    22   -37   43 33 53   46 55 29
     48  0  0    44 28  9   19 47  5    21   -38   42 50 27   46 10 28
     49  0  0    43 44  7   19 47  8    20   -39   42  7 10   45 25 36
     50  0  0    43  0 17   19 47 11    19   -40   41 24  4   44 40 53
     51  0  0    42 16 39   19 47 13    18   -41   40 41 12   43 56 24
     52  0  0    41 33 16   19 47 16    17   -42   39 58 35   43 12  9
     53  0  0    40 50 11   19 47 18    16   -42   39 16 15   42 28 12
     54  0  0    40  7 25   19 47 20    15   -43   38 34 15   41 44 34
     55  0  0    39 24 60   19 47 22    14   -44   37 52 35   41  1 18
     56  0  0    38 42 58   19 47 24    13   -45   37 11 19   40 18 24
     57  0  0    38  1 20   19 47 26    12   -46   36 30 26   39 35 56
     58  0  0    37 20  9   19 47 28    11   -47   35 50  0   38 53 55
     59  0  0    36 39 26   19 47 29    10   -47   35 10  2   38 12 22
     60  0  0    35 59 13   19 47 31     9   -48   34 30 32   37 31 19
     61  0  0    35 19 30   19 47 32     8   -49   33 51 33   36 50 48
     62  0  0    34 40 20   19 47 33     7   -50   33 13  5   36 10 50
     63  0  0    34  1 42   19 47 34     6   -50   32 35 10   35 31 25
  ............................. 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-|
--------------------------------------------------------------------U---U---