IOTA/IOTA-ES occultation update for (918) Itha / TYC 2929-02154-1 event on 2012 Dec 09, 14:49 UT Visible from N Australia Summary ------- On 2012 Dec 09 UT, the 21 km diameter asteroid (918) Itha will occult a 9.8 mag star in the constellation Auriga for observers along a path across N Australia. In the case of an occultation, the combined light of the asteroid and the star will drop by 5.1 mag to 14.9 mag (the magnitude of the asteroid) for at most 1.7 seconds. This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Alice Monet, historical astrometry from the MPC files (via AstDys), and the following catalogs for the star position: UCAC. The event at a glimpse ---------------------- * Rank: 36 * date and approx. time of event: 2012 Dec 09, 14:44 - 2012 Dec 09, 14:54 UT * geocentric midpoint of event [JD]: 2456271.117675 * magnitude of target star: 9.8 * magnitude drop [mag]: 5.1 * estimated maximum duration [s]: 1.7 * Moon: 19 % sunlit, 115° distance * Sun: 159° distance * rough path description: N Australia The occultation path -------------------- * approximate projected width [km]: 38 * 1 sigma uncertainty interval [path widths]: +/- 1.85 * 1 sigma uncertainty interval [seconds]: +/- 3.3 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .039 +/- .028) * 1 sigma uncertainty ellipse (major, minor, PA): ( .039", .028", 97° ) * approx speed of asteroid's shadow [km/s]: 12.5147 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 2929-02154-1 by 918 Itha on 2012 Dec 9 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 104 56 52 -40 0 0 14 54 8 1 33 -21 104 40 35 105 13 14 ... .. .. 106 14 25 105 49 18 -39 0 0 14 54 8 2 32 -23 105 32 59 106 5 40 ... .. .. 107 6 57 106 43 36 -38 0 0 14 54 7 3 32 -24 106 27 15 107 0 1 ... .. .. 108 1 29 107 39 52 -37 0 0 14 54 6 4 31 -25 107 23 28 107 56 22 ... .. .. 108 58 8 108 38 14 -36 0 0 14 54 4 6 31 -26 108 21 44 108 54 49 107 21 23 109 56 59 109 38 49 -35 0 0 14 54 2 7 30 -28 109 22 11 109 55 32 108 21 25 110 58 13 110 41 45 -34 0 0 14 53 59 8 29 -29 110 24 58 110 58 38 109 23 40 112 1 58 111 47 15 -33 0 0 14 53 56 9 29 -30 111 30 16 112 4 20 110 28 18 113 8 27 112 55 29 -32 0 0 14 53 52 11 28 -31 112 38 16 113 12 48 111 35 29 114 17 53 114 6 42 -31 0 0 14 53 48 12 27 -33 113 49 12 114 24 19 112 45 26 115 30 33 115 21 11 -30 0 0 14 53 43 13 27 -34 115 3 21 115 39 8 113 58 25 116 46 45 116 39 16 -29 0 0 14 53 37 15 26 -35 116 21 2 116 57 39 115 14 44 118 6 54 118 1 23 -28 0 0 14 53 31 16 25 -37 117 42 40 118 20 14 116 34 43 119 31 27 119 28 0 -27 0 0 14 53 23 18 24 -38 119 8 43 119 47 27 117 58 49 121 1 0 120 59 46 -26 0 0 14 53 15 19 23 -39 120 39 49 121 19 56 119 27 34 122 36 19 122 37 29 -25 0 0 14 53 5 21 22 -41 122 16 41 122 58 30 121 1 36 124 18 23 124 22 11 -24 0 0 14 52 55 22 21 -42 124 0 22 124 44 16 122 41 48 126 8 31 126 15 17 -23 0 0 14 52 42 24 20 -43 125 52 10 126 38 43 124 29 16 128 8 33 128 18 46 -22 0 0 14 52 29 25 18 -45 127 53 59 128 43 58 126 25 32 130 21 12 Latitude Latitude Latitude Latitude 129 0 0 -21 41 13 14 52 24 26 18 -45 -21 29 45 -21 52 44 -20 47 54 -22 35 57 130 0 0 -21 14 58 14 52 17 26 17 -46 -21 3 37 -21 26 23 -20 22 10 -22 9 9 131 0 0 -20 50 0 14 52 10 27 16 -46 -20 38 46 -21 1 18 -19 57 41 -21 43 40 132 0 0 -20 26 18 14 52 2 28 16 -47 -20 15 10 -20 37 30 -19 34 26 -21 19 29 133 0 0 -20 3 50 14 51 55 28 15 -47 -19 52 47 -20 14 57 -19 12 24 -20 56 34 134 0 0 -19 42 36 14 51 48 29 14 -47 -19 31 38 -19 53 37 -18 51 33 -20 34 54 135 0 0 -19 22 35 14 51 40 29 13 -48 -19 11 42 -19 33 31 -18 31 54 -20 14 29 136 0 0 -19 3 45 14 51 32 30 13 -48 -18 52 57 -19 14 37 -18 13 25 -19 55 17 137 0 0 -18 46 7 14 51 25 30 12 -48 -18 35 22 -18 56 54 -17 56 5 -19 37 19 138 0 0 -18 29 39 14 51 17 31 11 -49 -18 18 58 -18 40 22 -17 39 54 -19 20 32 139 0 0 -18 14 20 14 51 9 31 10 -49 -18 3 43 -18 25 0 -17 24 52 -19 4 56 140 0 0 -18 0 11 14 51 1 32 9 -49 -17 49 37 -18 10 47 -17 10 57 -18 50 30 141 0 0 -17 47 10 14 50 53 32 9 -49 -17 36 39 -17 57 43 -16 58 10 -18 37 15 142 0 0 -17 35 17 14 50 45 32 8 -49 -17 24 48 -17 45 48 -16 46 29 -18 25 9 143 0 0 -17 24 31 14 50 37 33 7 -49 -17 14 5 -17 35 0 -16 35 55 -18 14 12 144 0 0 -17 14 53 14 50 29 33 6 -49 -17 4 29 -17 25 19 -16 26 26 -18 4 23 145 0 0 -17 6 21 14 50 21 33 5 -49 -16 55 59 -17 16 45 -16 18 3 -17 55 42 146 0 0 -16 58 55 14 50 13 33 4 -49 -16 48 35 -17 9 18 -16 10 45 -17 48 8 147 0 0 -16 52 36 14 50 5 33 3 -49 -16 42 17 -17 2 57 -16 4 32 -17 41 42 148 0 0 -16 47 22 14 49 56 34 3 -49 -16 37 5 -16 57 42 -15 59 23 -17 36 23 149 0 0 -16 43 14 14 49 48 34 2 -48 -16 32 57 -16 53 33 -15 55 19 -17 32 10 150 0 0 -16 40 11 14 49 40 34 1 -48 -16 29 55 -16 50 30 -15 52 20 -17 29 4 151 0 0 -16 38 14 14 49 32 34 360 -48 -16 27 59 -16 48 32 -15 50 24 -17 27 5 152 0 0 -16 37 22 14 49 24 34 359 -48 -16 27 7 -16 47 40 -15 49 33 -17 26 12 153 0 0 -16 37 35 14 49 15 34 358 -47 -16 27 20 -16 47 53 -15 49 46 -17 26 26 154 0 0 -16 38 54 14 49 7 34 357 -47 -16 28 38 -16 49 12 -15 51 3 -17 27 45 155 0 0 -16 41 17 14 48 59 34 356 -46 -16 31 1 -16 51 36 -15 53 24 -17 30 12 156 0 0 -16 44 46 14 48 51 33 355 -46 -16 34 29 -16 55 6 -15 56 50 -17 33 44 157 0 0 -16 49 21 14 48 43 33 355 -45 -16 39 3 -16 59 42 -16 1 20 -17 38 24 158 0 0 -16 55 1 14 48 34 33 354 -45 -16 44 42 -17 5 24 -16 6 55 -17 44 10 159 0 0 -17 1 48 14 48 26 33 353 -44 -16 51 27 -17 12 11 -16 13 34 -17 51 4 160 0 0 -17 9 40 14 48 18 33 352 -44 -16 59 18 -17 20 6 -16 21 18 -17 59 5 161 0 0 -17 18 39 14 48 10 32 351 -43 -17 8 15 -17 29 7 -16 30 8 -18 8 14 162 0 0 -17 28 45 14 48 2 32 350 -42 -17 18 18 -17 39 15 -16 40 4 -18 18 31 163 0 0 -17 39 58 14 47 54 32 349 -42 -17 29 29 -17 50 30 -16 51 5 -18 29 56 164 0 0 -17 52 19 14 47 46 31 349 -41 -17 41 47 -18 2 54 -17 3 13 -18 42 31 165 0 0 -18 5 48 14 47 38 31 348 -40 -17 55 13 -18 16 26 -17 16 28 -18 56 15 166 0 0 -18 20 26 14 47 31 30 347 -40 -18 9 48 -18 31 8 -17 30 51 -19 11 10 167 0 0 -18 36 14 14 47 23 30 346 -39 -18 25 31 -18 46 59 -17 46 22 -19 27 15 168 0 0 -18 53 11 14 47 15 29 345 -38 -18 42 25 -19 4 0 -18 3 1 -19 44 32 169 0 0 -19 11 19 14 47 8 29 345 -37 -19 0 29 -19 22 13 -18 20 49 -20 3 1 170 0 0 -19 30 39 14 47 0 28 344 -36 -19 19 44 -19 41 37 -18 39 48 -20 22 44 171 0 0 -19 51 11 14 46 53 28 343 -36 -19 40 11 -20 2 14 -18 59 57 -20 43 40 172 0 0 -20 12 56 14 46 46 27 342 -35 -20 1 51 -20 24 5 -19 21 18 -21 5 52 173 0 0 -20 35 55 14 46 39 27 342 -34 -20 24 44 -20 47 10 -19 43 51 -21 29 19 174 0 0 -21 0 10 14 46 32 26 341 -33 -20 48 53 -21 11 31 -20 7 38 -21 54 4 175 0 0 -21 25 41 14 46 25 25 340 -32 -21 14 17 -21 37 8 -20 32 39 -22 20 7 176 0 0 -21 52 29 14 46 18 24 340 -31 -21 40 58 -22 4 4 -20 58 55 -22 47 30 177 0 0 -22 20 36 14 46 11 24 339 -30 -22 8 58 -22 32 18 -21 26 28 -23 16 13 178 0 0 -22 50 3 14 46 5 23 338 -29 -22 38 16 -23 1 53 -21 55 19 -23 46 20 179 0 0 -23 20 51 14 45 59 22 338 -28 -23 8 56 -23 32 50 -22 25 28 -24 17 50 180 0 0 -23 53 2 14 45 52 21 337 -27 -23 40 58 -24 5 10 -22 56 58 -24 50 45 -179 0 0 -24 26 37 14 45 46 20 336 -26 -24 14 24 -24 38 55 -23 29 49 -25 25 9 -178 0 0 -25 1 38 14 45 41 20 336 -25 -24 49 15 -25 14 7 -24 4 4 -26 1 1 -177 0 0 -25 38 8 14 45 35 19 335 -24 -25 25 33 -25 50 47 -24 39 44 -26 38 25 -176 0 0 -26 16 7 14 45 30 18 335 -23 -26 3 20 -26 28 59 -25 16 50 -27 17 23 -175 0 0 -26 55 38 14 45 25 17 334 -22 -26 42 39 -27 8 42 -25 55 24 -27 57 57 -174 0 0 -27 36 43 14 45 20 16 333 -21 -27 23 31 -27 50 1 -26 35 29 -28 40 9 -173 0 0 -28 19 25 14 45 15 15 333 -20 -28 5 58 -28 32 58 -27 17 6 -29 24 3 -172 0 0 -29 3 46 14 45 11 14 332 -19 -28 50 4 -29 17 35 -28 0 17 -30 9 42 -171 0 0 -29 49 49 14 45 6 13 332 -17 -29 35 50 -30 3 55 -28 45 6 -30 57 9 -170 0 0 -30 37 37 14 45 3 11 331 -16 -30 23 21 -30 52 1 -29 31 34 -31 46 27 -169 0 0 -31 27 14 14 44 59 10 331 -15 -31 12 38 -31 41 58 -30 19 44 -32 37 42 -168 0 0 -32 18 43 14 44 56 9 330 -14 -32 3 46 -32 33 48 -31 9 40 -33 30 57 -167 0 0 -33 12 8 14 44 53 8 329 -13 -32 56 48 -33 27 36 -32 1 24 -34 26 18 -166 0 0 -34 7 33 14 44 51 7 329 -11 -33 51 50 -34 23 27 -32 55 1 -35 23 50 -165 0 0 -35 5 5 14 44 48 5 328 -10 -34 48 54 -35 21 26 -33 50 33 -36 23 40 -164 0 0 -36 4 48 14 44 47 4 328 -9 -35 48 8 -36 21 40 -34 48 6 -37 25 56 -163 0 0 -37 6 49 14 44 46 3 327 -8 -36 49 37 -37 24 14 .. .. .. -38 30 46 -162 0 0 -38 11 15 14 44 45 2 326 -6 -37 53 27 -38 29 17 .. .. .. -39 38 21 -161 0 0 -39 18 15 14 44 44 0 326 -5 -38 59 48 .. .. .. .. .. .. .. .. .. Uncertainty in time = +/- 4 secs Prediction of 2012 Dec 3.0 Data for the target star ------------------------ * name: TYC 2929-02154-1 * constellation : Auriga * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 06 06 58.5017 DE: +39 44 36.089 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .016, .018 ) * V mag [mag]: 9.8 * B mag [mag]: 10.1 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (918) Itha approx. diameter [km]: 21 approx. diameter ["]: .015 distance from Earth [AU]: 1.91300 * orbital information: orbit source: Preston date of fit: 2012 Nov 29 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 958 number of rejected observations: 59 time covered by the observations: 1919 Aug 23 - 2012 Nov 25 1 sigma uncertainty ellipse (major, minor, PA): 0.036, 0.021, 98° remarks: * orbital elements for (918) Itha : Mean anomaly = 77.70268574 deg Arg. of pericenter = 16.30350594 deg Long. of node = 330.53568671 deg Inclination = 12.05048999 deg Eccentricity = 0.18780836 Semimajor axis = 2.86833074 AU Perihelion dist = 2.32963423 AU Mag: H = 10.50, G = 0.15 Epoch of elements : MJD 56270.61800000 TDT (2012 Dec 09.618) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Dec 9 918 Itha 14h 49.5m UT 9.8 6 6 58.502 39 44 36.09TYC 2929-02154-1 10.1 14.9 21 1.7 1.913 -2.815 -0.52 150.6308 39.742 -44.21 -22.89 14.8242 0.01166 -0.83130 -7.06277 -0.11070 -0.00146 -0.00161 2000 77.577300201212 9.00000 16.303506330.535687 12.0504900.18780836 2.8683307 2.329634210.7 5.00.15 RATE 2.0288980 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.039 0.028 97 2.85 0.028 0 0-3-1 056264.0020121209_2154-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Nov 29, 22:59 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org