Update for (38) Leda - December 3/4, 2000
Update computed by Jan Manek; issued 02 Dec 2000 09:30:20 +0100 (CET)
Jan Manek's update
IOTA/IOTA-ES occultation update for
(38) Leda / TYC 1891-00834-1 on December 3/4, 2000
visible from Russia, SE Belarus, NW Ukraine, SE Poland,
NW Slovakia, E Czechia, Austria, SE Switzerland, very N Italy,
S France, Spain and middle Portugal
Summary
In the night of December 3/4, 2000 a 10.4 mag star TYC 1891-00834-1 will be
occulted by a 120 km asteroid (38) Leda. This update is based on USNO/Flagstaff
and Gnosca astrometry for the asteroid and Tycho-2 star position.
The updated path shows ~0.5 path width south shift with time ~0.5 minute later compared to
Edwin Goffin's nominal prediction.
The path of this occultation runs over Russia south of Moscow ~22:18 UT,
SE Belarus ~22:20 UT, NW Ukraine ~22:20.6 UT, SE Poland ~22:21.5 UT,
NW Slovakia and E Czechia ~22:22 UT, Austria ~22:22.5 UT, SE Switzerland
and very N Italy ~22:23.5 UT, S France ~22:24.5 UT with Pic du Midi ~22:25 UT,
Spain ~22:26 UT and middle Portugal ~22:26.5 UT.
Goffin gives asteroid diameter as 71.8km, in such case the path would be narrower,
but I don't know his source, therefore I've used the rounded value 120km from Asteroids II database.
Star is faint, brightenss drop is only 1.4 magnitudes and location of target star isn't easy, but give it a try.
Good luck and clear sky !
The event at one glimpse:
* date and approx. UT time of event: December 3, 2000 @ 22:23 UT (Euro)
* magnitude of target star: 10.4
* magnitude drop [mag]: 1.4
* estimated maximum duration [s]: 16.3
* path description: given above
* Goffin's original chart reference: A00_1205
The occultation path:
* approximate ground width [km]: 130
* uncertainty [path widths]: 1.0
* uncertainty in time [s]: 20
* map: below
* remarks: Path uncertainities are given according to nominal star
position errors and expected asteroid positional accuracy.
!!!!!!!
Circles along path indicates the centerline for this event.
They are more accurate than the path limit lines.
!!!!!!!
Data for the target star:
* name: TYC 1891-00834-1
* constellation: Auriga
* J2000 position [h,m,s; o,',"]: 06h 25m 40.186s; +29o 08' 13.20"
* position source: Tycho-2
* estimated accuracy ["]: 0.05" (0.03", 0.04")
* V mag [mag]: 10.41
* B-V [mag]: +0.17
* remarks:
Target star is in SE Auriga, about 6.6 degrees north of red 2.9 mag
star mu Geminorum = SAO 78297. There are 3 stars ~7' east or SE of
targer form one can be selected as reference star with this event.
Close finding chart (prepared in GUIDE7):
* occulted star is in center - labeled with cross
* field is 3.0x3.0 degrees
* limiting magnitude is 12.0
* labeled stars have indicated SAO numbers
Data for the minor planet:
* general information:
number, name: (38) Leda
approx. diameter [km]: 120
* orbital information
orbit source: calculation Manek
source of used astrometry: USNO/Flagstaff (Ron Stone),
Gnosca (Stefano Sposetti)
number of used observations: 64 USNO, 6(1) Gnosca
number of rejected observations: 8 USNO
time covered by the observations: 1998 04 19 - 2000 11 26
rms residuals ["] (RA,DE): 0.09", 0.12"
estimated positional accuracy at epoch of event ["]: 0.08"
remarks: Gnosca frames of Stefano Sposetti were reduced by Raoul
Behrend; mean of the 6 original positions was used in computation.
Goffin gives diameter 71.8km in nominal prediction, I haven't found
possible source of this value, so I've left the diameter as 120km
which is rounded value from Asteroids II database.
Data for the event:
* UT date and time of least geocentric approach: 22:18.1 UT
* approx. V mag of minor planet at event [mag]: 11.5
* geocentric parallax of minor planet ["]: 6.259
* magnitude drop [mag]: 1.4
* estimated maximum duration [s]: 16.3
* apparent motion of minor planet ["/h]: 26.02
* angular distance to moon, phase of moon [deg,%]: 118, 46%
* remarks:
Calculator(s): Jan Manek
Path coordinates:
Altitude
E. Longitude Latitude U.T. star sun
........ shortened ..........................
o ' " o ' " h m s o o
66 0 0 55 1 41 22 14 58 61 -45
64 0 0 55 1 42 22 15 15 62 -46
62 0 0 55 0 29 22 15 31 63 -47
60 0 0 54 58 1 22 15 47 63 -47
58 0 0 54 54 19 22 16 4 63 -48
56 0 0 54 49 21 22 16 21 64 -49
54 0 0 54 43 9 22 16 38 64 -50
52 0 0 54 35 41 22 16 54 64 -51
50 0 0 54 26 56 22 17 11 65 -52
48 0 0 54 16 55 22 17 29 65 -53
46 0 0 54 5 36 22 17 46 65 -54
44 0 0 53 52 58 22 18 3 65 -55
42 0 0 53 39 1 22 18 21 65 -55
40 0 0 53 23 43 22 18 39 65 -56
38 0 0 53 7 4 22 18 57 65 -57
36 0 0 52 49 2 22 19 15 64 -58
34 0 0 52 29 36 22 19 33 64 -58
32 0 0 52 8 45 22 19 51 64 -59
30 0 0 51 46 27 22 20 10 63 -60
28 0 0 51 22 41 22 20 29 63 -61
26 0 0 50 57 26 22 20 48 62 -61
24 0 0 50 30 40 22 21 7 62 -62
22 0 0 50 2 22 22 21 26 61 -62
20 0 0 49 32 31 22 21 46 61 -63
18 0 0 49 1 4 22 22 5 60 -63
16 0 0 48 28 2 22 22 25 59 -63
14 0 0 47 53 22 22 22 45 58 -64
12 0 0 47 17 3 22 23 5 57 -64
10 0 0 46 39 5 22 23 25 56 -64
8 0 0 45 59 26 22 23 46 55 -64
6 0 0 45 18 6 22 24 6 54 -64
4 0 0 44 35 5 22 24 27 53 -63
2 0 0 43 50 21 22 24 47 51 -63
0 0 0 43 3 56 22 25 8 50 -63
- 2 0 0 42 15 48 22 25 28 49 -62
- 4 0 0 41 25 60 22 25 49 47 -61
- 6 0 0 40 34 31 22 26 9 46 -61
- 8 0 0 39 41 23 22 26 29 44 -60
- 10 0 0 38 46 38 22 26 49 43 -59
- 12 0 0 37 50 18 22 27 9 41 -58
- 14 0 0 36 52 25 22 27 28 39 -57
........ 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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