Update for (87) Sylvia - October 6, 1998
Update computed by Martin Federspiel; issued 28 Sep 1998 12:31:13 +0200 (CEST)
Martin Federspiel's update
IOTA/IOTA-ES occultation update for
(87) Sylvia/ACT 51138 event on 1998 October 6
visible from Marokko/Canary Islands(?) and central America
Summary
On the early morning (UT) of 1998 October 8 the large minor planet
(87) Sylvia will occult an 11 mag star in Cetus for observers along a
270 km wide path which crosses the Sahara dessert, passes a bit south
of the Canary Islands and then on the other side of the Atlantic ocean
goes over Venezuela, Kolumbia, and Panama. Tenerife is on the northern
limit of the estimated error range. The nearby fullmoon will make the
event rather difficult to observe.
The event at one glimpse:
* date and approx. UT time of event: 1998 October 6 @ 4h UT
* magnitude of target star: 11.1
* magnitude drop [mag]: 1.1
* estimated maximum duration [s]: 21
* rough path description: Algeria, Marokko, south of Canary Islands,
Venezuela, Kolumbia, Panama
The occultation path:
* approximate widths [km]: 270
* more detailed path description: Algeria, southern Marokko, 300 km south
of Tenerife, northern Venezuela, northern Kolumbia, Panama
* uncertainty [path widths]: 1.2
* map: attached
* remarks: Tenerife is near the northern limit of the estimated error range
Data for the target star:
* name: ACT 51138=TYC 4685 02546
* constellation: Cetus
* J2000 position [h,m,s; °,',"]: RA 1h 39m 38.777s DE -3°15'33.48"
* position source: ACT
* estimated accuracy ["]: 0.10 (?)
* V mag [mag]: 11.1
* remarks: flag X in Tycho (problem case); consequence for accuracy in ACT?
Data for the minor planet:
* general information:
mumber, name: (87) Sylvia
approx. diameter [km]: 271
* orbital information
orbit source: calculation Federspiel
source of used astrometry: CAMC, Bordeaux, and USNO positions
number of used observations: 126
number of rejected observations:
time covered by the observations: 1986-1998
rms residuals ["] (RA,DE): 0.17",0.17"
estimated positional accuracy at epoch of event ["]: 0.15"
remarks:
Data for the event:
* UT date and time of least geocentric approach: 1998 Oct 6 @ 4h 3m 34s UT
* least geocentric distance ["]: 1.21"
* uncertainty in time [s]: 20
* approx. V mag of minor planet at event [mag]: 11.7
* geocentric parallax of minor planet ["]: 3.85
* magnitude drop [mag]: 1.1
* estimated maximum duration [s]: 21
* apparent motion of minor planet ["/h]: 27.54"/h
* angular distance to moon, phase of moon [°,%]: 10°, 100%
* remarks: strong interference by moonlight
Calculator(s): Federspiel
Path coordinates:
Lat. Long. hh:mm:ss UT StarAlt° StarAzi° SunAlt° SunAzi°
33.96 29.32 3:55:42. ! 8.2 260.5 -1.8 94.8
32.75 19.18 3:55:59. ! 16.6 254.8 -10.2 89.4
31.77 12.73 3:56:15. ! 22.1 251.2 -15.6 86.2
30.87 7.59 3:56:32. ! 26.4 248.2 -20.0 83.7
30.03 3.19 3:56:49. ! 30.2 245.7 -23.8 81.7
29.22 -.72 3:57: 6. ! 33.5 243.3 -27.3 79.9
28.44 -4.28 3:57:22. ! 36.6 241.1 -30.4 78.3
27.68 -7.58 3:57:39. ! 39.5 239.0 -33.3 76.9
26.95 -10.66 3:57:56. ! 42.1 237.0 -36.1 75.6
26.23 -13.57 3:58:13. ! 44.6 234.9 -38.8 74.3
25.53 -16.34 3:58:30. ! 47.0 232.8 -41.3 73.1
24.84 -19.00 3:58:46. ! 49.3 230.7 -43.7 72.0
24.16 -21.54 3:59: 3. ! 51.4 228.6 -46.1 70.9
23.49 -24.01 3:59:20. ! 53.5 226.3 -48.4 69.8
22.83 -26.39 3:59:37. ! 55.4 223.9 -50.6 68.7
22.18 -28.71 3:59:53. ! 57.3 221.5 -52.8 67.7
21.55 -30.97 4: 0:10. ! 59.1 218.8 -54.9 66.6
20.91 -33.19 4: 0:27. ! 60.8 215.9 -57.0 65.4
20.29 -35.35 4: 0:44. ! 62.5 212.8 -59.0 64.3
19.68 -37.48 4: 1: 1. ! 64.0 209.5 -61.0 63.0
19.07 -39.58 4: 1:17. ! 65.4 205.8 -63.0 61.7
18.47 -41.64 4: 1:34. ! 66.7 201.8 -64.9 60.3
17.87 -43.68 4: 1:51. ! 67.9 197.5 -66.8 58.7
17.28 -45.70 4: 2: 8. ! 69.0 192.7 -68.7 56.9
16.70 -47.70 4: 2:24. ! 69.9 187.6 -70.6 54.8
16.13 -49.69 4: 2:41. ! 70.6 182.1 -72.4 52.4
15.55 -51.66 4: 2:58. ! 71.1 176.3 -74.2 49.5
14.99 -53.63 4: 3:15. ! 71.5 170.2 -75.9 46.0
14.43 -55.59 4: 3:31. ! 71.6 164.0 -77.6 41.5
13.87 -57.54 4: 3:48. ! 71.6 157.8 -79.2 35.8
13.33 -59.50 4: 4: 5. ! 71.3 151.7 -80.6 28.3
12.78 -61.46 4: 4:22. ! 70.8 145.9 -81.8 18.3
12.24 -63.42 4: 4:39. ! 70.1 140.4 -82.7 5.3
11.71 -65.39 4: 4:55. ! 69.3 135.4 -83.2 349.6
11.18 -67.37 4: 5:12. ! 68.3 130.7 -83.1 333.0
10.66 -69.36 4: 5:29. ! 67.1 126.5 -82.5 317.9
10.14 -71.37 4: 5:46. ! 65.8 122.7 -81.4 305.9
9.62 -73.40 4: 6: 2. ! 64.4 119.2 -80.0 296.7
9.12 -75.45 4: 6:19. ! 62.9 116.2 -78.4 289.9
8.61 -77.54 4: 6:36. ! 61.3 113.4 -76.6 284.8
8.12 -79.65 4: 6:53. ! 59.7 110.9 -74.8 280.8
7.63 -81.80 4: 7: 9. ! 57.9 108.7 -72.8 277.7
7.14 -84.00 4: 7:26. ! 56.0 106.8 -70.8 275.2
6.66 -86.24 4: 7:43. ! 54.1 105.0 -68.7 273.3
6.19 -88.55 4: 7:60. ! 52.0 103.4 -66.5 271.6
5.72 -90.92 4: 8:17. ! 49.9 102.0 -64.2 270.3
5.27 -93.36 4: 8:33. ! 47.7 100.7 -61.8 269.2
4.82 -95.90 4: 8:50. ! 45.4 99.6 -59.3 268.3
4.38 -98.55 4: 9: 7. ! 42.9 98.6 -56.8 267.5
3.95 -101.32 4: 9:24. ! 40.3 97.7 -54.1 266.9
3.53 -104.26 4: 9:40. ! 37.5 96.8 -51.2 266.4
3.13 -107.39 4: 9:57. ! 34.5 96.1 -48.1 266.0
2.75 -110.79 4:10:14. ! 31.2 95.5 -44.8 265.7
2.39 -114.54 4:10:31. ! 27.6 94.9 -41.1 265.4
2.06 -118.81 4:10:48. ! 23.5 94.5 -36.9 265.3
1.79 -123.95 4:11: 4. ! 18.4 94.0 -31.8 265.2
1.64 -131.09 4:11:21. ! 11.4 93.7 -24.7 265.2
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Martin Federspiel ******** E-mail: martin@astro.unibas.ch
Astronomisches Institut ******** oder: federspi@astro.unibas.ch
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