|
|
Updated: 2008 OCT 30, 13:51 UT
Event Rank : 97
(The event Rank is a measure of the likelihood of observing an event, and is equal to the probability of at least one successful observation by a team of two observers spaced 1/8 path width just inside opposite sides of the predicted path. An event rank of 100 indicates that the prediction is expected to be very accurate).
THE UPDATED PATH
Note: The duration given in the line below is the interval during which the occultation shadow sweeps across the Earth - please see the minute markers on the map to determine the approximate time for your location.
On 2008 Nov 03 UT, the 121 km diameter asteroid (176) Iduna will occult a 11.2 mag star in the constellation Orion for observers along a path across Papua - New Guinea, and across Australia from Cape York across western Queensland, southeastern Northern Territory and central South Australia to Fowlers Bay.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.8 mag to 12.7 mag (the magnitude of the asteroid) for at most 10.4 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Alice Monet, TMO astrometry for the asteroid kindly provided by Bill Owen, historical astrometry from the MPC files (via AstDys), and the following catalogs for the star position: UCAC.
Additional details of this and other events are available at Steve Preston's website at http://www.asteroidoccultation.com/
EVENT DETAILS SUMMARY :Important Note regarding Accuracy:
The uncertainty interval in path widths given above (and shown as a 1-sigma uncertainty ellipse on the plot) refers to RMS deviation and is applied as a +/- range. In other words, a path uncertainty of 1.0 path widths means that the actual center of the asteroid's shadow path should fall within plus or minus 1 path width of the plotted path center. However path errors larger than 1 sigma have been observed so observers should be alert for primary occultations within plus or minus 3 sigma of the updated path.
Further, almost all asteroidal satellites discovered so far have been found within 10 diameters of the asteroid (since this distance is deep enough within the gravitational well to be stable over long timescales). Therefore, if monitoring for secondary events, observing out to about 10 path-widths either side of the predicted track remains worthwhile.
We therefore recommend that you monitor for events if your observing location is up to +/- 10 path-widths from the predicted track. If not monitoring for occultations by secondary bodies you should observe from locations within 3 sigma of the nominal path.
In terms of time, the predictions are now usually accurate to about +/- 0.3 minute so you should be most attentive during the predicted minute of the event. However if intending to catch a potential satellite occultation you should start observing at least 10 times the predicted central duration before the predicted closest approach time for your location, and continue for a similar period afterwards.
Centre Star Star Sun Path Limits Error Limits
E. Longitude Latitude U.T. Alt Az Alt Limit 1 Limit 2 Limit 3 Limit 4
o ' " o ' " h m s o o o o ' " o ' " o ' " o ' "
Longitude Longitude Longitude Longitude
144 48 43 - 1 0 0 16 19 9 70 93 -53 144 13 2 145 24 15 143 44 24 145 52 35
144 34 54 - 2 0 0 16 19 19 70 90 -53 143 59 10 145 10 30 143 30 29 145 38 53
144 20 41 - 3 0 0 16 19 28 69 88 -52 143 44 52 144 56 21 143 16 7 145 24 47
144 6 2 - 4 0 0 16 19 38 69 85 -52 143 30 8 144 41 47 143 1 18 145 10 17
143 50 56 - 5 0 0 16 19 48 69 82 -52 143 14 56 144 26 48 142 46 2 144 55 22
143 35 24 - 6 0 0 16 19 57 68 80 -51 142 59 17 144 11 22 142 30 17 144 40 2
143 19 24 - 7 0 0 16 20 7 68 78 -51 142 43 10 143 55 30 142 14 3 144 24 16
143 2 56 - 8 0 0 16 20 17 67 76 -50 142 26 33 143 39 10 141 57 19 144 8 2
142 45 58 - 9 0 0 16 20 26 67 73 -50 142 9 26 143 22 22 141 40 5 143 51 22
142 28 31 -10 0 0 16 20 36 66 71 -50 141 51 48 143 5 4 141 22 18 143 34 12
142 10 32 -11 0 0 16 20 45 66 70 -49 141 33 38 142 47 17 141 3 59 143 16 33
141 52 2 -12 0 0 16 20 55 65 68 -49 141 14 55 142 28 58 140 45 6 142 58 24
141 32 58 -13 0 0 16 21 4 65 66 -48 140 55 38 142 10 7 140 25 38 142 39 44
141 13 20 -14 0 0 16 21 14 64 65 -48 140 35 46 141 50 43 140 5 34 142 20 31
140 53 6 -15 0 0 16 21 23 63 63 -47 140 15 17 141 30 45 139 44 53 142 0 44
140 32 15 -16 0 0 16 21 33 63 62 -47 139 54 10 141 10 10 139 23 32 141 40 22
140 10 46 -17 0 0 16 21 42 62 60 -46 139 32 23 140 48 58 139 1 31 141 19 24
139 48 37 -18 0 0 16 21 51 61 59 -46 139 9 55 140 27 8 138 38 48 140 57 48
139 25 47 -19 0 0 16 22 1 60 58 -45 138 46 44 140 4 37 138 15 21 140 35 32
139 2 13 -20 0 0 16 22 10 59 57 -45 138 22 49 139 41 24 137 51 8 140 12 36
138 37 53 -21 0 0 16 22 19 59 56 -44 137 58 6 139 17 26 137 26 7 139 48 56
138 12 46 -22 0 0 16 22 28 58 55 -44 137 32 35 138 52 43 137 0 16 139 24 31
137 46 49 -23 0 0 16 22 37 57 55 -43 137 6 12 138 27 11 136 33 32 138 59 20
137 20 0 -24 0 0 16 22 46 56 54 -43 136 38 56 138 0 49 136 5 53 138 33 18
136 52 16 -25 0 0 16 22 55 55 53 -42 136 10 42 137 33 34 135 37 16 138 6 25
136 23 34 -26 0 0 16 23 4 54 53 -42 135 41 29 137 5 22 135 7 38 137 38 37
135 53 51 -27 0 0 16 23 13 53 52 -41 135 11 14 136 36 11 134 36 55 137 9 52
135 23 4 -28 0 0 16 23 22 52 52 -40 134 39 51 136 5 59 134 5 4 136 40 6
Latitude Latitude Latitude Latitude
134 0 0 -30 31 45 16 23 44 50 51 -39 -29 13 11 -31 49 2 -28 9 21 -32 50 0
133 0 0 -32 12 58 16 23 58 48 50 -38 -30 57 23 -33 27 24 -29 56 3 -34 26 12
132 0 0 -33 47 50 16 24 11 46 50 -37 -32 34 59 -34 59 41 -31 35 54 -35 56 28
131 0 0 -35 16 54 16 24 24 45 50 -36 -34 6 31 -36 26 22 -33 9 31 -37 21 18
130 0 0 -36 40 38 16 24 35 43 50 -35 -35 32 32 -37 47 54 -34 37 25 -38 41 8
129 0 0 -37 59 27 16 24 45 42 50 -34 -36 53 28 -39 4 41 -36 0 5 -39 56 21
128 0 0 -39 13 45 16 24 55 41 50 -33 -38 9 42 -40 17 6 -37 17 56 -41 7 18
127 0 0 -40 23 51 16 25 4 39 50 -32 -39 21 37 -41 25 26 -38 31 20 -42 14 17
Uncertainty in time = +/- 4 secs
[Prediction of 2008 Oct 30.0]
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
[Timing Details]
[Reporting Details]
[Report Form]
[Asteroid Occultation Results]
[Top of Page][Return to Home Page]