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Preamble:
The July 8 occultation by asteroid 22 Kalliope and its 20-35km satellite Linus is one of the most important occultations of 2004.
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Linus has been followed since its discovery by the world's largest telescopes using adaptive optics techniques, with a view to improve its orbital parameters and to derive the physical characteristics of Kalliope and the Kalliope/Linus system. This image was taken on 2004 June 28 by the VLT. Nevertheless, determining a definitive orbit for Linus has proven to be particularly difficult.
Observation of an occultation by Linus will provide an additional astrometric data point with an accuracy between ten and thirty times greater than can be obtained by using telescopes in the 8-10 metre class. Consequently, this event is generating considerable interest amongst professional researchers. Two other occultations by Kalliope/Linus this year have proved unsuccesful (May 14 in Australia and June 5 in Europe). It will therefore be up to Australasian observers to capture this event which would be the first time that a confirmed satellite of an asteroid has been observed by the occultation technique. Kalliope's shadow will cross the mid-Queensland coast in the region of Townsville and sweep across Australia, directly crossing Perth. The accuracy of this track is very high. |
The shadow of Linus, while previously expected to sweep across Bundaberg and southeastern SA, is now expected to pass slightly to the north of the track of kalliope. On the map below (provided by IMCEE) the wide blue track is the path of Kalliope while the more narrow blue track to its north is the expected path of Linus. Note that there is still a significant uncertainty in the accuracy with which Linus's track is known.
Co-ordinates of the centre of the expected path of Linus are available here. The track of Linus enters Australia between Cairns and Townsville and exits the west coast about 125 km north of Perth. Times at which the tracks cross the Australian coast are expected to be:
| East coast crossing : | Kalliope : | 16:11:21 UT |
| Linus : | 16:11:46 UT | |
| West coast crossing : | Kalliope : | 16:15:38 UT |
| Linus : | 16:16:01 UT |
While important, these events will unfortunately not be easy to observe as the magnitude drop at occultation is expected to be only about 0.8, or close to the level at which visual observers become unable to distinguish an event. Photoelectric or video observation of the events is preferred.
(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 the time for your location)
Links for further information::
You are strongly urged to visit the following link which provides much greater detail as the scientific value of the Kalliope/Linus occultations together with extensive information about large-telescope observations to date:
http://www.imcce.fr/observateur/target/targobs.php?target=Kalliope#k
KALLIOPE 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 ' "
Latitude Latitude Latitude Latitude
110 0 0 -34 17 36 16 16 31 60 275 -76 -33 23 56 -35 11 29 -33 3 36 -35 32 2
111 0 0 -33 58 58 16 16 21 60 274 -77 -33 5 12 -34 52 58 -32 44 49 -35 13 33
112 0 0 -33 39 58 16 16 12 59 273 -78 -32 46 5 -34 34 4 -32 25 40 -34 54 41
113 0 0 -33 20 34 16 16 2 58 272 -78 -32 26 35 -34 14 47 -32 6 7 -34 35 27
114 0 0 -33 0 48 16 15 52 57 271 -79 -32 6 42 -33 55 7 -31 46 12 -34 15 50
115 0 0 -32 40 39 16 15 43 56 270 -79 -31 46 27 -33 35 5 -31 25 55 -33 55 50
116 0 0 -32 20 8 16 15 33 56 269 -80 -31 25 49 -33 14 40 -31 5 15 -33 35 28
117 0 0 -31 59 14 16 15 24 55 268 -80 -31 4 49 -32 53 53 -30 44 12 -33 14 43
118 0 0 -31 37 58 16 15 14 54 267 -81 -30 43 27 -32 32 43 -30 22 47 -32 53 36
119 0 0 -31 16 20 16 15 5 53 266 -81 -30 21 42 -32 11 11 -30 1 0 -32 32 6
120 0 0 -30 54 19 16 14 56 52 265 -81 -29 59 35 -31 49 17 -29 38 51 -32 10 14
121 0 0 -30 31 57 16 14 46 51 264 -81 -29 37 6 -31 27 1 -29 16 20 -31 48 1
122 0 0 -30 9 12 16 14 37 50 263 -81 -29 14 16 -31 4 23 -28 53 27 -31 25 25
123 0 0 -29 46 6 16 14 28 50 262 -81 -28 51 4 -30 41 23 -28 30 12 -31 2 27
124 0 0 -29 22 39 16 14 19 49 262 -81 -28 27 30 -30 18 2 -28 6 37 -30 39 8
125 0 0 -28 58 50 16 14 10 48 261 -81 -28 3 36 -29 54 19 -27 42 40 -30 15 28
126 0 0 -28 34 41 16 14 1 47 260 -80 -27 39 20 -29 30 15 -27 18 22 -29 51 27
127 0 0 -28 10 10 16 13 52 46 259 -80 -27 14 44 -29 5 51 -26 53 44 -29 27 4
128 0 0 -27 45 19 16 13 43 45 259 -79 -26 49 47 -28 41 6 -26 28 45 -29 2 21
129 0 0 -27 20 8 16 13 34 44 258 -79 -26 24 31 -28 16 0 -26 3 26 -28 37 18
130 0 0 -26 54 37 16 13 26 43 257 -78 -25 58 54 -27 50 34 -25 37 47 -28 11 54
131 0 0 -26 28 46 16 13 17 42 257 -77 -25 32 58 -27 24 49 -25 11 49 -27 46 11
132 0 0 -26 2 36 16 13 9 41 256 -77 -25 6 43 -26 58 44 -24 45 32 -27 20 8
133 0 0 -25 36 8 16 13 0 40 256 -76 -24 40 9 -26 32 21 -24 18 57 -26 53 46
134 0 0 -25 9 20 16 12 52 40 255 -75 -24 13 17 -26 5 38 -23 52 3 -26 27 6
135 0 0 -24 42 15 16 12 44 39 254 -74 -23 46 7 -25 38 37 -23 24 51 -26 0 7
136 0 0 -24 14 52 16 12 36 38 254 -73 -23 18 39 -25 11 19 -22 57 21 -25 32 50
137 0 0 -23 47 11 16 12 28 37 253 -73 -22 50 55 -24 43 43 -22 29 35 -25 5 16
138 0 0 -23 19 14 16 12 20 36 253 -72 -22 22 53 -24 15 50 -22 1 32 -24 37 25
139 0 0 -22 51 1 16 12 13 35 252 -71 -21 54 36 -23 47 41 -21 33 14 -24 9 17
140 0 0 -22 22 32 16 12 5 34 252 -70 -21 26 3 -23 19 16 -21 4 39 -23 40 53
141 0 0 -21 53 48 16 11 58 33 251 -69 -20 57 15 -22 50 35 -20 35 50 -23 12 14
142 0 0 -21 24 49 16 11 51 32 251 -68 -20 28 13 -22 21 39 -20 6 46 -22 43 19
143 0 0 -20 55 36 16 11 44 31 250 -67 -19 58 57 -21 52 29 -19 37 29 -22 14 11
144 0 0 -20 26 9 16 11 37 30 250 -66 -19 29 28 -21 23 6 -19 7 58 -21 44 48
145 0 0 -19 56 30 16 11 31 29 250 -65 -18 59 45 -20 53 29 -18 38 15 -21 15 13
146 0 0 -19 26 38 16 11 24 28 249 -64 -18 29 51 -20 23 40 -18 8 20 -20 45 25
147 0 0 -18 56 35 16 11 18 26 249 -63 -17 59 46 -19 53 39 -17 38 14 -20 15 25
148 0 0 -18 26 21 16 11 12 25 248 -62 -17 29 30 -19 23 27 -17 7 57 -19 45 13
149 0 0 -17 55 57 16 11 6 24 248 -61 -16 59 4 -18 53 5 -16 37 31 -19 14 52
150 0 0 -17 25 24 16 11 1 23 248 -60 -16 28 29 -18 22 33 -16 6 55 -18 44 20
151 0 0 -16 54 41 16 10 55 22 247 -59 -15 57 46 -17 51 52 -15 36 11 -18 13 39
152 0 0 -16 23 51 16 10 50 21 247 -58 -15 26 54 -17 21 2 -15 5 20 -17 42 50
153 0 0 -15 52 54 16 10 45 20 247 -57 -14 55 56 -16 50 6 -14 34 21 -17 11 54
154 0 0 -15 21 50 16 10 40 19 246 -56 -14 24 52 -16 19 2 -14 3 17 -16 40 51
155 0 0 -14 50 40 16 10 36 18 246 -55 -13 53 42 -15 47 53 -13 32 7 -16 9 42
156 0 0 -14 19 26 16 10 32 17 246 -54 -13 22 28 -15 16 39 -13 0 53 -15 38 27
157 0 0 -13 48 8 16 10 28 16 246 -53 -12 51 10 -14 45 20 -12 29 35 -15 7 9
158 0 0 -13 16 47 16 10 24 15 245 -52 -12 19 50 -14 13 58 -11 58 15 -14 35 46
159 0 0 -12 45 23 16 10 20 14 245 -51 -11 48 27 -13 42 34 -11 26 52 -14 4 22
160 0 0 -12 13 58 16 10 17 13 245 -49 -11 17 3 -13 11 8 -10 55 29 -13 32 55
161 0 0 -11 42 33 16 10 14 11 245 -48 -10 45 39 -12 39 41 -10 24 6 -13 1 28
162 0 0 -11 11 8 16 10 11 10 244 -47 -10 14 16 -12 8 14 - 9 52 43 -12 30 0
163 0 0 -10 39 44 16 10 9 9 244 -46 - 9 42 54 -11 36 48 - 9 21 22 -11 58 33
164 0 0 -10 8 22 16 10 7 8 244 -45 - 9 11 34 -11 5 24 - 8 50 3 -11 27 8
165 0 0 - 9 37 3 16 10 5 7 244 -44 - 8 40 18 -10 34 3 - 8 18 48 -10 55 46
166 0 0 - 9 5 48 16 10 3 6 244 -43 - 8 9 6 -10 2 45 - 7 47 36 -10 24 27
167 0 0 - 8 34 38 16 10 2 5 244 -42 - 7 37 59 - 9 31 32 - 7 16 31 - 9 53 13
168 0 0 - 8 3 34 16 10 1 4 243 -41 - 7 6 58 - 9 0 24 - 6 45 31 - 9 22 4
169 0 0 - 7 32 36 16 10 0 3 243 -40 - 6 36 3 - 8 29 23 - 6 14 37 - 8 51 1
170 0 0 - 7 1 45 16 9 59 2 243 -38 - 6 5 16 - 7 58 28 - 5 43 52 - 8 20 5
171 0 0 - 6 31 3 16 9 59 0 243 -37 .. .. .. - 7 27 42 .. .. .. - 7 49 18
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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