Update for (895) Helio - April 28, 2002
Update computed by Jan Manek; issued 18 Apr 2002 22:30:00 +0100 (CEST)
Jan Manek's update
IOTA/IOTA-ES occultation update for
(895) Helio / TYC 5456-01750-1 on April 28, 2002
visible from Africa, Crete and SW Turkey
Summary
In the late evening of April 28, 2002 a 10.4 mag star TYC 5456-01750-1
will be occulted by a 147 km asteroid (895) Helio. This update is based on
USNO/Flagstaff and TMO astrometry for the asteroid and combined Tycho-2/UCAC star position.
The updated path shows ~1.5 path width south shift with time ~0.8 minutes earlier compared to
Edwin Goffin's nominal prediction.
Updated path runs over NW Africa at 20:58 to 21:01.3 UT, then after over Crete 21:01.7 UT and finally
SW Turkey at low altitude at 21:02 UT. Within uncertainties is somewhat larger area, but still probably without observers;
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 28, 2002 @ 21:01 UT
* magnitude of target star: 10.4
* magnitude drop [mag]: 3.4
* estimated maximum duration [s]: 11.1
* path description: given above
* Goffin's original chart reference: A02_0444
The occultation path:
* approximate ground width [km]: 150
* uncertainty [path widths]: 0.9
* uncertainty in time [s]: 12
* 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 5456-01750-1
* constellation: Hydra
* J2000 position [h,m,s; o,',"]: 09h 00m 08.2970s; -13o 48' 31.393"
* position source: UCAC position combined with Tycho-2 proper motion
* estimated accuracy ["]: 0.01" (0.009", 0.011")
* V mag [mag]: 10.35
* B-V [mag]: +1.30
* remarks:
Recent UCAC position was provided by Marion and Norbert Zacharias.
Target star is in middle Hydra, about 8.5 degrees southwest of 2.0 mag star alpha Hydrae = SAO 136871,
rather far from familiar places.
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.
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: (895) Helio
approx. diameter [km]: 147
* orbital information
orbit source: calculation Manek
source of used astrometry: USNO/Flagstaff (Ron Stone), TMO (Bill Owen)
number of used observations: 102 USNO, 2 TMO
number of rejected observations: 5 USNO
time covered by the observations: 1998 04 21 - 2002 04 13
rms residuals ["] (RA,DE): 0.09", 0.10"
estimated positional accuracy at epoch of event ["]: 0.07", 0.06"
remarks:
Data for the event:
* UT date and time of least geocentric approach: 20:54.3 UT
* approx. V mag of minor planet at event [mag]: 13.8
* geocentric parallax of minor planet ["]: 3.287
* magnitude drop [mag]: 3.4
* estimated maximum duration [s]: 11.1
* apparent motion of minor planet ["/h]: 24.66
* angular distance to moon, phase of moon [deg,%]: 100, 96%
* 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 ' "
- 18 0 0 12 43 6 20 58 1 58 -22 11 54 39 13 31 45
- 16 0 0 13 57 29 20 58 18 56 -24 13 8 60 14 46 11
- 14 0 0 15 11 42 20 58 35 54 -25 14 23 11 16 0 24
- 12 0 0 16 25 32 20 58 51 51 -26 15 37 2 17 14 13
- 10 0 0 17 38 50 20 59 6 49 -27 16 50 22 18 27 29
- 8 0 0 18 51 26 20 59 21 47 -29 18 3 2 19 40 2
- 6 0 0 20 3 12 20 59 35 45 -30 19 14 52 20 51 42
- 4 0 0 21 13 57 20 59 49 43 -31 20 25 44 22 2 21
- 2 0 0 22 23 34 21 0 1 40 -32 21 35 29 23 11 50
0 0 0 23 31 55 21 0 13 38 -33 22 43 59 24 20 2
2 0 0 24 38 53 21 0 25 36 -33 23 51 7 25 26 50
4 0 0 25 44 23 21 0 35 34 -34 24 56 48 26 32 8
6 0 0 26 48 17 21 0 45 32 -35 26 0 55 27 35 51
8 0 0 27 50 33 21 0 55 30 -35 27 3 24 28 37 53
10 0 0 28 51 5 21 1 3 28 -36 28 4 9 29 38 11
11 0 0 29 20 41 21 1 7 27 -36 28 33 52 30 7 39
12 0 0 29 49 49 21 1 11 26 -36 29 3 8 30 36 41
13 0 0 30 18 30 21 1 15 25 -36 29 31 56 31 5 14
14 0 0 30 46 44 21 1 18 24 -37 30 0 17 31 33 20
15 0 0 31 14 29 21 1 22 23 -37 30 28 10 32 0 57
16 0 0 31 41 45 21 1 25 22 -37 30 55 34 32 28 6
17 0 0 32 8 33 21 1 28 21 -37 31 22 30 32 54 46
18 0 0 32 34 53 21 1 31 20 -37 31 48 57 33 20 58
19 0 0 33 0 43 21 1 34 19 -37 32 14 56 33 46 40
20 0 0 33 26 4 21 1 36 18 -37 32 40 25 34 11 53
21 0 0 33 50 56 21 1 39 17 -37 33 5 25 34 36 37
22 0 0 34 15 19 21 1 41 16 -37 33 29 56 35 0 52
23 0 0 34 39 13 21 1 43 15 -37 33 53 57 35 24 38
24 0 0 35 2 37 21 1 45 14 -37 34 17 30 35 47 54
25 0 0 35 25 32 21 1 47 14 -37 34 40 32 36 10 41
26 0 0 35 47 58 21 1 49 13 -37 35 3 6 36 32 58
27 0 0 36 9 54 21 1 50 12 -37 35 25 10 36 54 46
28 0 0 36 31 21 21 1 52 11 -37 35 46 45 37 16 6
29 0 0 36 52 19 21 1 53 10 -37 36 7 51 37 36 56
30 0 0 37 12 48 21 1 54 9 -37 36 28 28 37 57 17
31 0 0 37 32 48 21 1 56 8 -37 36 48 36 38 17 9
32 0 0 37 52 19 21 1 57 7 -37 37 8 15 38 36 32
33 0 0 38 11 21 21 1 57 7 -37 37 27 25 38 55 27
34 0 0 38 29 55 21 1 58 6 -37 37 46 6 39 13 53
35 0 0 38 48 0 21 1 59 5 -36 38 4 18 39 31 51
........................... shortened .............................
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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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