Update for (280) Philia - May 12/13, 2002

Jan Manek's update

                    IOTA/IOTA-ES occultation update for
       (280) Philia / TYC 6747-01271-1 = SAO 182961 on May 12/13, 2002
                       visible from India and Russia


Summary 

In the night of May 12/13, 2002 a 10.1 mag star SAO 182961 = TYC 6747-01271-1 will be occulted by a 48 km asteroid (280) Philia. This update is based on USNO/Flagstaff and OFXB astrometry for the asteroid and combined UCAC1 star position.

The updated path shows ~6 path width north shift with time ~0.7 minutes earlier compared to Edwin Goffin's nominal prediction.

Updated path runs over Russia around 22:34 UT with Kuybyshev on north limit, later along Ukraine/Russia border with Kharkov on south limit ~22:34.6 UT and Kiev just south of path ~22:35.1 UT. Belarus is in path around 22:35.5 UT with Minsk on north limit. Follows NE Poland ~22:36 UT and south Sweden ~22:36.5 UT at low altitudes. Within uncertainties is for example whole Poland, northeast Geramny, whole Denmark and all Baltic countries - Lithuania, Latvia, Estonia. Please check the path chart for details.

According to Jean Lecacheux "this asteroid is a slow rotator (P=64 h) and could be a binary system", so observers in a wider area than path depicted in charts should try to observe.

Clear sky and good luck !!!

The event at one glimpse:
 * date and approx. UT time of event: May 12, 2002 @ 22:35 UT
 * magnitude of target star: 10.1
 * magnitude drop [mag]: 5.0
 * estimated maximum duration [s]: 3.6
 * path description: given above
 * Goffin's original chart reference: A02_0523

The occultation path:
 * approximate ground width [km]: 220
 * uncertainty [path widths]: 3.3
 * uncertainty in time [s]: 11
 * map: below
 * remarks: Path uncertainties are given according to nominal star
    position errors and expected asteroid positional accuracy.

Data for the target star:
 * name: SAO 182961 = PPM 263515 = TYC 6747-01271-1
 * constellation: Libra
 * J2000 position [h,m,s; o,',"]: 14h 53m 03.2210s; -23o 44' 23.961"
 * position source: UCAC1
 * estimated accuracy ["]: 0.02" (0.010", 0.008")
 * V mag [mag]: 10.05
 * B-V [mag]: +0.51
 * remarks:
    Target star is in southwest Libra, about 2.9 degrees NW of 3.3 mag red star sigma Librae = SAO 183139.
    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 GUIDE7):
 * occulted star is in center - labeled with cross
 * field is 3.0x3.0 degrees
 * limiting magnitude is 13.0
 * labeled stars have indicated SAO numbers
 * remarks:





Data for the minor planet:
 * general information:
     number, name: (280) Philia
     approx. diameter [km]: 48
 * orbital information
     orbit source: calculation Manek
     source of used astrometry: USNO/Flagstaff (Ron Stone), OFXB (Raoul Behrend)
     number of used observations: 79 USNO, 3 OFXB
     number of rejected observations: 12 USNO
     time covered by the observations: 1998 06 29 - 2002 05 03
     rms residuals ["] (RA,DE): 0.11", 0.13"
     estimated positional accuracy at epoch of event ["]: 0.08", 0.09"
     remarks:

Data for the event:
 * UT date and time of least geocentric approach: 22:35.1 UT
 * approx. V mag of minor planet at event [mag]: 15.1
 * geocentric parallax of minor planet ["]: 4.113
 * magnitude drop [mag]: 5.0
 * estimated maximum duration [s]: 3.6
 * apparent motion of minor planet ["/h]: 31.11
 * angular distance to moon, phase of moon [deg,%]: 167, 0%
 * 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  '  "
     54  0  0    53 13 51   22 33 28     6   -13   54 23 18   52 10 44
     53  0  0    52 55 26   22 33 31     6   -14   54  3 23   51 53 27
     52  0  0    52 38 33   22 33 34     7   -14   53 45 12   51 37 34
     51  0  0    52 23  9   22 33 37     8   -15   53 28 38   51 23  3
     50  0  0    52  9 11   22 33 40     8   -15   53 13 39   51  9 52
     49  0  0    51 56 37   22 33 43     9   -16   53  0 12   50 57 59
     48  0  0    51 45 24   22 33 47     9   -16   52 48 14   50 47 23
     47  0  0    51 35 33   22 33 51    10   -17   52 37 43   50 38  3
     46  0  0    51 27  0   22 33 54    10   -17   52 28 37   50 29 57
     45  0  0    51 19 45   22 33 59    10   -17   52 20 54   50 23  4
     44  0  0    51 13 48   22 34  3    11   -18   52 14 33   50 17 25
     43  0  0    51  9  6   22 34  7    11   -18   52  9 33   50 12 58
     42  0  0    51  5 39   22 34 11    11   -18   52  5 53   50  9 43
     41  0  0    51  3 28   22 34 16    12   -19   52  3 33   50  7 38
     40  0  0    51  2 32   22 34 21    12   -19   52  2 32   50  6 45
     39  0  0    51  2 49   22 34 25    12   -19   52  2 50   50  7  3
     38  0  0    51  4 22   22 34 30    12   -19   52  4 26   50  8 32
     37  0  0    51  7  8   22 34 35    13   -19   52  7 22   50 11 12
     36  0  0    51 11 10   22 34 40    13   -19   52 11 37   50 15  2
     35  0  0    51 16 26   22 34 45    13   -19   52 17 12   50 20  4
     34  0  0    51 22 58   22 34 50    13   -19   52 24  7   50 26 18
     33  0  0    51 30 47   22 34 55    13   -19   52 32 23   50 33 44
     32  0  0    51 39 52   22 35  1    13   -19   52 42  2   50 42 23
     31  0  0    51 50 16   22 35  6    13   -19   52 53  6   50 52 15
     30  0  0    52  1 59   22 35 11    13   -19   53  5 35   51  3 22
     29  0  0    52 15  3   22 35 16    13   -19   53 19 31   51 15 45
     28  0  0    52 29 30   22 35 22    13   -19   53 34 59   51 29 25
     27  0  0    52 45 21   22 35 27    13   -19   53 51 59   51 44 23
     26  0  0    53  2 40   22 35 32    13   -19   54 10 36   52  0 42
     25  0  0    53 21 28   22 35 38    12   -18   54 30 54   52 18 23
     24  0  0    53 41 50   22 35 43    12   -18   54 52 59   52 37 29
     23  0  0    54  3 50   22 35 48    12   -18   55 16 56   52 58  3
     22  0  0    54 27 32   22 35 53    12   -17   55 42 52   53 20  7
     21  0  0    54 53  1   22 35 58    11   -17   56 10 58   53 43 47
     20  0  0    55 20 26   22 36  4    11   -17   56 41 25   54  9  5
     19  0  0    55 49 53   22 36  9    10   -16   57 14 28   54 36  8
     18  0  0    56 21 35   22 36 13    10   -15   57 50 29   55  5  2
     17  0  0    56 55 44   22 36 18     9   -15   58 29 54   55 35 55
     16  0  0    57 32 39   22 36 23     9   -14   59 13 24   56  8 57
     15  0  0    58 12 43   22 36 28     8   -14   60  2  2   56 44 20
     14  0  0    58 56 29   22 36 32     7   -13   60 57 30   57 22 20
     13  0  0    59 44 46   22 36 36     7   -12   62  3  8   58  3 19
     12  0  0    60 38 52   22 36 40     6   -11   63 27 28   58 47 46
     11  0  0    61 41  4   22 36 44     5   -10   66 19 15   59 36 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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