Update for (19) Fortuna - October 4, 1998

Martin Federspiel's update

                     IOTA/IOTA-ES occultation update for 
                (19) Fortuna/TYC 1393 01391 event on 1998 Oct 4
                visible from Scottland, Danmark, southern Sweden

Summary 

   

The event at one glimpse:
 * date and approx. UT time of event: 1998 Oct 4 @ 4h 15m UT
 * magnitude of target star: 10.5
 * magnitude drop [mag]: 1.9
 * estimated maximum duration [s]: 5
 * rough path description: Scottland, Danmark, southern Sweden

The occultation path:
 * approximate widths [km]: 150
 * more detailed path description: possible northern Ireland, Scottland
   (Glasgow, Edinburgh), Danmark (Viborg, Randers, north of Kopenhagen
   and Hälsingborg), Sweden (Halstad, southern Öland)  
 * uncertainty [path widths]: 2.5
 * map: attached
 * remarks: path shifted about 0.15" north compared to nominal prediction
   mainly due to difference between Tycho and ACT star position

Data for the target star:
 * name: TYC 1393 01391
 * constellation: Cancer
 * J2000 position [h,m,s; °,',"]: RA 8 50 13.609 DE +16 19 13.56
 * position source: ACT
 * estimated accuracy ["]: 0.05
 * V mag [mag]: 10.5
 * remarks: 0.3" difference between ACT and Tycho declination of the star

Data for the minor planet:
 * general information:
     mumber, name: (19) Fortuna
     approx. diameter [km]: 150
 * orbital information
     orbit source: Federspiel
     source of used astrometry: CAMC, Bordeaux, Hipparcos
     number of used observations: 166
     number of rejected observations:
     time covered by the observations: 1985-1997
     rms residuals ["] (RA,DE): 0.20, 0.19
     estimated positional accuracy at epoch of event ["]: 0.2
     remarks:

Data for the event:
 * UT date and time of least geocentric approach: 1998 Oct 4  4h 16m 46s UT
 * least geocentric distance ["]: 1.85
 * uncertainty in time [s]: 12
 * approx. V mag of minor planet at event [mag]: 12.15
 * geocentric parallax of minor planet ["]: 3.37
 * magnitude drop [mag]: 1.9
 * estimated maximum duration [s]: 5
 * apparent motion of minor planet ["/h]: 60.47
 * angular distance to moon, phase of moon [°,%]: 143°,96%+
 * remarks:

Calculator(s): Federspiel





Path coordinates:
     Lat.     Long. hh:mm:ss UT  StarAlt° StarAzi°  SunAlt°  SunAzi°
     49.07   -46.23  4:13:59. !      4.5     69.9    -42.1     27.4
     52.56   -31.52  4:14: 6. !     14.2     81.5    -33.8     43.2
     54.11   -22.70  4:14:13. !     19.6     89.0    -28.9     51.8
     55.08   -15.46  4:14:19. !     23.8     95.4    -24.9     58.5
     55.73    -9.06  4:14:26. !     27.3    101.2    -21.4     64.3
     56.15    -3.22  4:14:33. !     30.4    106.7    -18.2     69.5
     56.40     2.20  4:14:39. !     33.1    112.0    -15.2     74.3
     56.51     7.28  4:14:46. !     35.7    117.2    -12.5     78.7
     56.50    12.08  4:14:53. !     38.0    122.2     -9.8     82.8
     56.40    16.63  4:14:59. !     40.1    127.1     -7.3     86.6
     56.21    20.97  4:15: 6. !     42.1    131.9     -4.9     90.3
     55.95    25.10  4:15:13. !     43.9    136.7     -2.6     93.8
     55.62    29.06  4:15:19. !     45.6    141.5      -.3     97.1

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Martin Federspiel                 ******** E-mail: martin@astro.unibas.ch
Astronomisches Institut           ******** oder: federspi@astro.unibas.ch
der Universitaet Basel            **** oder: federspielm@ubaclu.unibas.ch
Venusstr. 7                             Telefon: (CH)-61/2055413
CH-4102 Binningen (Schweiz)             Fax:     (CH)-61/2055455
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