3/19/99 Asterope Update
Subject: Sun. night Asterope occ'n, Hawaii, Calif. to NYC
Here is Jan Manek's update for the occultation of a 10.4-mag. star
in Canis Minor by the 108km asteroid 233 Asterope. The path has
shifted 3.5 +/-2 path-widths north of the basic IOTA/Goffin prediction,
with the time 3 minutes early. This means that the occultation
could occur in Hawaii around 5:38 UT March 22nd UT, central Calif.
at 5:50 UT, Las Vegas at 5:51, central Colorado at 5:53, just north
of (maybe over) Kansas City at 5:54; central Illinois & northern
Indiana at 5:55 U.T.; and northern Ohio, most of Pennsylvania, northern
New Jersey, New York City, and Long Island at 5:56 U.T. (56 minutes
after midnight EST). But with the current uncertainties in the path,
the event could occur as far north as San Francisco, Ft. Collins,
Des Moines, Chicago, Detroit, Buffalo, Albany, and Boston, or as
far south as Los Angeles, Flagstaff, Puebla, Wichita, St. Louis,
Cincinnati, DC, Fredericksburg (VA), and Delaware. The prediction
might be refined during the next couple of days, especially if CCD
observations of both the star and the relatively slowly-moving
asteroid on the same frame can be obtained and reduced with USNO
A2.0 or ACT data. IOTA's finder chart for locating the star, and
maps showing the updated path, can be found at
"http://members.home.net/dega/astchart.htm"Asteroidal Chart Web
Page
Future updates will also be available there, and at IOTA's main
site at http://www.lunar-occultations.com/iota/ once it is restored
(that should occur sometime today), and on the IOTA phone line
at 301-474-4945. Besides encouraging observers at fixed sites to
try to time the occultation, those with a mobile capability are
encouraged to try to observe from locations in the path to fill
gaps in local coverage of the fixed sites. We plan an expedition from
the DC area to attempt observations across Pennsylvania, but the
long-range weather forecast is unfavorable for this area.
David Dunham, IOTA, 1999 March 19, 6h U.T.
______________________________________________________________________
Date: Thu, 18 Mar 1999 19:08:06 +0100
To: Joan and David Dunham <dunham@erols.com
From: Jan Manek <jmanek@mbox.vol.cz
Subject: Update for (233) Asterope on March 21/22, 1999
IOTA/IOTA-ES occultation update for
(233) Asterope / TYC 0773 01067 1 event on 1999, March 21/22
visible from Hawai and most US from west to east
Summary
On the night March 21/22, 1999 will be occulted 10.4 mag star by a 108km
asteroid (233) Asterope. This update is based on USNO/Flagstaff and TMO
astrometry for asteroid and ACT star position. The asteroid is moving
quite
slowly; only 12"/hour; so the duration will be rather long ~19 seconds.
The
magnitude drop is large so the event should be well observable. The main
source
of uncertainity is the star's position.
The event at one glimpse:
* date and approx. UT time of event: March, 3, 1999 @ 05:38 UT (Hawai)
05:50 UT (W USA) - 05:57 UT (E USA)
* magnitude of target star: 10.4
* magnitude drop [mag]: 3.0
* estimated maximum duration [s]: 19.2
* path description: See above. Observers up to 200km of
this path are within expected path errors. For details consult
the maps on the Web site given above.
The occultation path:
* approximate width [km]: 110
* uncertainty [path widths]: 2
* uncertainty in time [s]: 40
* remarks: Path uncertainities are given according to nominal star
position
errors and expected asteroid positional accuracy.
CONCERNING the maps showing the updated path on the Web:
Please follow the circles rather than the plotted path.
!!!!!!!
Circles along the path are OCCULT exactly calculated centerline
points.
!!!!!!!
Remember the +/-2 path-widths uncertainty.
Data for the target star:
* name: TYC 0773 01067 1
* constellation: Canis Minor
* J2000 position [h,m,s; o,',"]: 07h 36m 09.498s; +12o 03' 30.28"
* position source: ACT
* estimated accuracy ["]: 0.08" (0.06", 0.04")
* V mag [mag]: 10.40
* B-V [mag]: +1.41
* remarks:
TYCHO quality flag is 7 indicating LOW quality position together with
X flag indicating it is not suitable as astrometric reference.
TRC gives position close to ACT, but this problem remains.
True star position error may be much larger than nominal.
Data for the minor planet:
* general information:
number, name: (233) Asterope
approx. diameter [km]: 108
* orbital information
orbit source: calculation Manek
source of used astrometry: USNO/Flagstaff (Ron Stone), TMO (Bill
Owen)
number of used observations: 38 USNO, 7 TMO
number of rejected observations: 1 USNO (1998 12 28.390828)
time covered by the observations: 1998 11 04 - 1999 03 13
rms residuals ["] (RA,DE): 0.09", 0.07"
estimated positional accuracy at epoch of event ["]: 0.08"
remarks: Rejection of the one USNO position was not significant.
Data for the event:
* UT date and time of least geocentric approach: 05:38:54 UT
* approx. V mag of minor planet at event [mag]: 13.3
* geocentric parallax of minor planet ["]: 3.755
* magnitude drop [mag]: 3.0
* estimated maximum duration [s]: 19.2
* apparent motion of minor planet ["/h]: 11.94
* angular distance to moon, phase of moon [deg,%]: 53, 25%
* remarks:
Centerline path coordinates:
Altitude
E. Longitude Latitude U.T. star sun
-162 00 00 + 13 39 39 5 35 43 77 -10
-160 00 00 + 15 02 52 5 36 32 79 -12
-158 00 00 + 16 24 49 5 37 22 81 -14
-156 00 00 + 17 45 18 5 38 11 82 -16
-154 00 00 + 19 04 06 5 39 00 82 -18
-152 00 00 + 20 21 04 5 39 48 81 -20
-150 00 00 + 21 36 01 5 40 35 80 -21
-148 00 00 + 22 48 49 5 41 22 79 -23
-146 00 00 + 23 59 22 5 42 07 77 -25
-144 00 00 + 25 07 34 5 42 52 75 -27
-142 00 00 + 26 13 20 5 43 35 73 -28
-140 00 00 + 27 16 38 5 44 17 71 -30
-138 00 00 + 28 17 24 5 44 58 69 -31
-136 00 00 + 29 15 37 5 45 37 67 -33
-134 00 00 + 30 11 17 5 46 16 65 -34
-132 00 00 + 31 04 24 5 46 53 64 -35
-130 00 00 + 31 54 58 5 47 28 62 -37
-128 00 00 + 32 43 00 5 48 03 60 -38
-126 00 00 + 33 28 31 5 48 36 58 -39
-124 00 00 + 34 11 35 5 49 08 56 -40
-122 00 00 + 34 52 12 5 49 39 54 -41
-120 00 00 + 35 30 24 5 50 08 52 -42
-118 00 00 + 36 06 16 5 50 37 50 -43
-116 00 00 + 36 39 48 5 51 04 49 -44
-114 00 00 + 37 11 03 5 51 30 47 -44
-112 00 00 + 37 40 04 5 51 55 45 -45
-110 00 00 + 38 06 54 5 52 19 44 -46
-108 00 00 + 38 31 34 5 52 42 42 -46
-106 00 00 + 38 54 07 5 53 04 40 -47
-104 00 00 + 39 14 36 5 53 25 39 -47
-102 00 00 + 39 33 01 5 53 45 37 -48
-100 00 00 + 39 49 26 5 54 04 35 -48
- 98 00 00 + 40 03 52 5 54 22 34 -48
- 96 00 00 + 40 16 21 5 54 40 32 -49
- 94 00 00 + 40 26 54 5 54 56 30 -49
- 92 00 00 + 40 35 33 5 55 12 29 -49
- 90 00 00 + 40 42 19 5 55 27 27 -49
- 88 00 00 + 40 47 13 5 55 41 26 -49
- 86 00 00 + 40 50 16 5 55 54 24 -49
- 84 00 00 + 40 51 28 5 56 06 23 -49
- 82 00 00 + 40 50 51 5 56 18 21 -48
- 80 00 00 + 40 48 25 5 56 28 20 -48
- 78 00 00 + 40 44 10 5 56 38 18 -48
- 76 00 00 + 40 38 06 5 56 48 16 -48
- 74 00 00 + 40 30 14 5 56 56 15 -47
- 72 00 00 + 40 20 33 5 57 04 13 -47
- 70 00 00 + 40 09 03 5 57 10 12 -46
- 68 00 00 + 39 55 45 5 57 17 10 -46
- 66 00 00 + 39 40 37 5 57 22 9 -45
- 64 00 00 + 39 23 40 5 57 26 7 -45
Calculator: Manek