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Updated: 2009 DEC 15, 18:28 UT
Event Rank : 98
(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 2009 Dec 20 UT, the 75 km diameter asteroid (535) Montague will occult a 11.4 mag star in the constellation Gemini for observers along a path across Australia, from Uladulla and Canberra across New South Wales to Cobar, and across northern South Australia and Western Australia to Onslow.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.6 mag to 12.8 mag (the magnitude of the asteroid) for at most 6.5 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
172 1 27 -49 0 0 16 0 0 7 322 -4 173 8 8 170 54 25 173 53 16 170 8 36
170 27 33 -48 0 0 16 0 2 8 323 -5 171 33 28 169 21 14 172 18 5 168 35 54
168 53 53 -47 0 0 16 0 6 10 324 -7 169 59 9 167 48 12 170 43 18 167 3 16
167 20 16 -46 0 0 16 0 9 11 325 -8 168 24 58 166 15 6 169 8 44 165 30 31
165 46 32 -45 0 0 16 0 14 13 327 -10 166 50 47 164 41 47 167 34 13 163 57 29
164 12 29 -44 0 0 16 0 19 14 328 -11 165 16 23 163 8 5 165 59 33 162 23 59
162 37 59 -43 0 0 16 0 24 16 329 -13 163 41 37 161 33 49 164 24 35 160 49 51
161 2 50 -42 0 0 16 0 30 17 330 -14 162 6 17 159 58 47 162 49 8 159 14 53
159 26 50 -41 0 0 16 0 37 18 331 -16 160 30 14 158 22 50 161 13 0 157 38 56
157 49 50 -40 0 0 16 0 45 20 333 -17 158 53 15 156 45 45 159 36 1 156 1 46
156 11 36 -39 0 0 16 0 53 21 334 -19 157 15 10 155 7 20 157 58 0 154 23 12
154 31 56 -38 0 0 16 1 1 23 335 -20 155 35 45 153 27 22 156 18 44 152 43 1
152 50 37 -37 0 0 16 1 11 24 336 -22 153 54 48 151 45 37 154 38 0 151 0 56
151 7 23 -36 0 0 16 1 21 26 338 -23 152 12 4 150 1 49 152 55 35 149 16 43
149 21 57 -35 0 0 16 1 32 27 339 -25 150 27 17 148 15 41 151 11 12 147 30 2
147 34 2 -34 0 0 16 1 44 29 341 -27 148 40 10 146 26 52 149 24 35 145 40 34
145 43 15 -33 0 0 16 1 57 30 342 -28 146 50 23 144 35 0 147 35 25 143 47 54
143 49 13 -32 0 0 16 2 10 31 344 -30 144 57 33 142 39 39 145 43 20 141 51 35
141 51 27 -31 0 0 16 2 25 33 346 -31 143 1 13 140 40 18 143 47 54 139 51 4
139 49 23 -30 0 0 16 2 40 34 348 -33 141 0 52 138 36 19 141 48 39 137 45 40
Latitude Latitude Latitude Latitude
138 0 0 -29 8 12 16 2 55 35 350 -34 -28 33 57 -29 42 53 -28 10 54 -30 6 44
137 0 0 -28 40 35 16 3 3 36 351 -35 -28 6 32 -29 15 4 -27 43 37 -29 38 46
136 0 0 -28 13 34 16 3 11 36 352 -36 -27 39 42 -28 47 51 -27 16 54 -29 11 25
135 0 0 -27 47 7 16 3 19 37 353 -37 -27 13 27 -28 21 13 -26 50 46 -28 44 38
134 0 0 -27 21 16 16 3 28 37 354 -37 -26 47 47 -27 55 11 -26 25 13 -28 18 28
133 0 0 -26 56 2 16 3 36 38 355 -38 -26 22 42 -27 29 45 -26 0 16 -27 52 55
132 0 0 -26 31 23 16 3 45 38 356 -38 -25 58 14 -27 4 56 -25 35 55 -27 27 58
131 0 0 -26 7 21 16 3 53 39 357 -39 -25 34 22 -26 40 43 -25 12 9 -27 3 39
130 0 0 -25 43 56 16 4 2 39 358 -40 -25 11 7 -26 17 8 -24 49 0 -26 39 57
129 0 0 -25 21 8 16 4 11 40 359 -40 -24 48 29 -25 54 11 -24 26 28 -26 16 52
128 0 0 -24 58 58 16 4 19 40 1 -41 -24 26 27 -25 31 51 -24 4 33 -25 54 26
127 0 0 -24 37 25 16 4 28 40 2 -41 -24 5 3 -25 10 9 -23 43 15 -25 32 37
126 0 0 -24 16 30 16 4 37 41 3 -42 -23 44 17 -24 49 5 -23 22 34 -25 11 27
125 0 0 -23 56 13 16 4 46 41 4 -42 -23 24 8 -24 28 40 -23 2 31 -24 50 56
124 0 0 -23 36 35 16 4 55 41 5 -43 -23 4 38 -24 8 53 -22 43 6 -24 31 3
123 0 0 -23 17 35 16 5 4 42 6 -43 -22 45 45 -23 49 45 -22 24 18 -24 11 49
122 0 0 -22 59 13 16 5 13 42 8 -44 -22 27 31 -23 31 15 -22 6 9 -23 53 15
121 0 0 -22 41 30 16 5 22 42 9 -44 -22 9 55 -23 13 25 -21 48 38 -23 35 19
120 0 0 -22 24 25 16 5 31 42 10 -44 -21 52 57 -22 56 13 -21 31 45 -23 18 3
119 0 0 -22 8 0 16 5 40 42 11 -45 -21 36 38 -22 39 41 -21 15 30 -23 1 26
118 0 0 -21 52 14 16 5 49 42 12 -45 -21 20 58 -22 23 48 -20 59 54 -22 45 29
117 0 0 -21 37 6 16 5 58 42 14 -45 -21 5 57 -22 8 35 -20 44 57 -22 30 11
116 0 0 -21 22 38 16 6 7 42 15 -45 -20 51 35 -21 54 1 -20 30 38 -22 15 33
115 0 0 -21 8 49 16 6 16 42 16 -45 -20 37 51 -21 40 6 -20 16 58 -22 1 34
114 0 0 -20 55 40 16 6 25 42 17 -46 -20 24 47 -21 26 52 -20 3 57 -21 48 16
113 0 0 -20 43 10 16 6 34 42 18 -46 -20 12 21 -21 14 16 -19 51 35 -21 35 37
Uncertainty in time = +/- 3 secs
Prediction of 2009 Dec 16.0
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
[Timing Details]
[Reporting Details]
[Report Form]
[Asteroid Occultation Results]
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