IOTA/IOTA-ES occultation update for (60558) Echeclus / UCAC2 24877181 event on 2012 Jul 21, 13:47 UT Visible from E Russia, N China Summary ------- On 2012 Jul 21 UT, the 55 km diameter asteroid (60558) Echeclus will occult a 12.8 mag star in the constellation Ophiuchus for observers along a path across E Russia, N China. In the case of an occultation, the combined light of the asteroid and the star will drop by 5.5 mag to 18.3 mag (the magnitude of the asteroid) for at most 4.8 seconds. This update is based on historical astrometry from the MPC files (via AstDys), and the following catalogs for the star position: UCAC. The event at a glimpse ---------------------- * Rank: 3 * date and approx. time of event: 2012 Jul 21, 13:54 - 2012 Jul 21, 14:02 UT * geocentric midpoint of event [JD]: 2456130.083 * magnitude of target star: 12.8 * magnitude drop [mag]: 5.5 * estimated maximum duration [s]: 4.8 * Moon: 7 % sunlit, 112° distance * Sun: 140° distance * rough path description: E Russia, N China The occultation path -------------------- * approximate projected width [km]: 99 * 1 sigma uncertainty interval [path widths]: +/- 19.08 * 1 sigma uncertainty interval [seconds]: +/- 113.8 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .285 +/- .209) * 1 sigma uncertainty ellipse (major, minor, PA): ( .286", .209", 92° ) * approx speed of asteroid's shadow [km/s]: 11.3891 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of UCAC2 24877181 by 60558 Echeclus on 2012 Jul 21 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 32 41 55 0 0 13 54 22 0 237 -13 171 5 29 ... .. .. ... .. .. ... .. .. 169 51 57 54 0 0 13 54 23 2 235 -14 168 25 15 171 17 47 ... .. .. ... .. .. Latitude Latitude Latitude Latitude 168 0 0 53 18 18 13 54 24 3 233 -15 53 50 34 52 46 34 .. .. .. .. .. .. 167 0 0 52 56 1 13 54 25 4 232 -16 53 28 11 52 24 22 .. .. .. .. .. .. 166 0 0 52 33 47 13 54 26 5 231 -16 53 5 51 52 2 15 .. .. .. .. .. .. 165 0 0 52 11 38 13 54 27 6 231 -17 52 43 36 51 40 11 .. .. .. .. .. .. 164 0 0 51 49 34 13 54 28 6 230 -17 52 21 25 51 18 14 .. .. .. .. .. .. 163 0 0 51 27 36 13 54 29 7 229 -18 51 59 21 50 56 22 .. .. .. .. .. .. 162 0 0 51 5 45 13 54 31 8 228 -18 51 37 23 50 34 36 .. .. .. .. .. .. 161 0 0 50 44 1 13 54 33 8 227 -19 51 15 32 50 12 59 .. .. .. .. .. .. 160 0 0 50 22 24 13 54 35 9 227 -19 50 53 49 49 51 29 .. .. .. .. .. .. 159 0 0 50 0 57 13 54 37 10 226 -20 50 32 15 49 30 8 .. .. .. .. .. .. 158 0 0 49 39 39 13 54 39 11 225 -20 50 10 51 49 8 57 .. .. .. .. .. .. 157 0 0 49 18 32 13 54 42 11 224 -20 49 49 36 48 47 56 .. .. .. .. .. .. 156 0 0 48 57 35 13 54 44 12 224 -21 49 28 33 48 27 5 .. .. .. .. .. .. 155 0 0 48 36 49 13 54 47 13 223 -21 49 7 40 48 6 27 .. .. .. .. .. .. 154 0 0 48 16 16 13 54 50 13 222 -22 48 47 0 47 46 0 .. .. .. .. .. .. 153 0 0 47 55 56 13 54 53 14 221 -22 48 26 33 47 25 46 .. .. .. .. .. .. 152 0 0 47 35 48 13 54 56 15 220 -22 48 6 19 47 5 45 .. .. .. .. .. .. 151 0 0 47 15 55 13 55 0 15 220 -23 47 46 19 46 45 58 .. .. .. .. .. .. 150 0 0 46 56 16 13 55 3 16 219 -23 47 26 33 46 26 26 .. .. .. .. .. .. 149 0 0 46 36 52 13 55 7 17 218 -23 47 7 2 46 7 9 .. .. .. .. .. .. 148 0 0 46 17 44 13 55 11 17 217 -23 46 47 48 45 48 7 .. .. .. 30 18 6 147 0 0 45 58 52 13 55 15 18 216 -24 46 28 49 45 29 21 .. .. .. 30 1 40 146 0 0 45 40 17 13 55 19 19 215 -24 46 10 7 45 10 52 .. .. .. 29 45 30 145 0 0 45 21 59 13 55 23 19 215 -24 45 51 42 44 52 40 .. .. .. 29 29 35 144 0 0 45 3 58 13 55 28 20 214 -24 45 33 35 44 34 45 .. .. .. 29 13 56 143 0 0 44 46 15 13 55 32 21 213 -24 45 15 46 44 17 9 .. .. .. 28 58 35 142 0 0 44 28 52 13 55 37 21 212 -25 44 58 16 43 59 51 .. .. .. 28 43 30 141 0 0 44 11 47 13 55 42 22 211 -25 44 41 5 43 42 52 .. .. .. 28 28 42 140 0 0 43 55 1 13 55 47 22 210 -25 44 24 14 43 26 12 .. .. .. 28 14 11 139 0 0 43 38 35 13 55 52 23 209 -25 44 7 42 43 9 52 .. .. .. 27 59 59 138 0 0 43 22 30 13 55 57 24 209 -25 43 51 30 42 53 52 .. .. .. 27 46 4 137 0 0 43 6 44 13 56 3 24 208 -25 43 35 40 42 38 12 .. .. .. 27 32 28 136 0 0 42 51 20 13 56 8 25 207 -25 43 20 10 42 22 54 .. .. .. 27 19 10 135 0 0 42 36 18 13 56 14 25 206 -25 43 5 2 42 7 56 .. .. .. 27 6 11 134 0 0 42 21 36 13 56 20 26 205 -25 42 50 15 41 53 20 .. .. .. 26 53 31 133 0 0 42 7 17 13 56 26 26 204 -25 42 35 50 41 39 6 .. .. .. 26 41 11 132 0 0 41 53 20 13 56 32 27 203 -25 42 21 48 41 25 13 .. .. .. 26 29 9 131 0 0 41 39 45 13 56 38 27 202 -25 42 8 9 41 11 44 .. .. .. 26 17 28 130 0 0 41 26 33 13 56 44 28 201 -25 41 54 52 40 58 36 .. .. .. 26 6 6 129 0 0 41 13 45 13 56 50 28 200 -25 41 41 59 40 45 52 .. .. .. 25 55 5 128 0 0 41 1 19 13 56 57 29 199 -25 41 29 29 40 33 31 .. .. .. 25 44 23 127 0 0 40 49 18 13 57 3 29 198 -25 41 17 23 40 21 34 .. .. .. 25 34 3 126 0 0 40 37 39 13 57 10 30 197 -24 41 5 40 40 10 0 .. .. .. 25 24 2 125 0 0 40 26 25 13 57 17 30 196 -24 40 54 22 39 58 49 .. .. .. 25 14 23 124 0 0 40 15 36 13 57 23 30 195 -24 40 43 29 39 48 3 .. .. .. 25 5 4 123 0 0 40 5 10 13 57 30 31 194 -24 40 32 59 39 37 42 .. .. .. 24 56 7 122 0 0 39 55 10 13 57 37 31 193 -24 40 22 55 39 27 44 .. .. .. 24 47 31 121 0 0 39 45 34 13 57 44 31 192 -23 40 13 16 39 18 12 .. .. .. 24 39 16 120 0 0 39 36 23 13 57 51 32 191 -23 40 4 1 39 9 4 .. .. .. 24 31 22 119 0 0 39 27 37 13 57 58 32 190 -23 39 55 12 39 0 21 .. .. .. 24 23 51 118 0 0 39 19 16 13 58 5 32 189 -23 39 46 49 38 52 4 .. .. .. 24 16 41 117 0 0 39 11 21 13 58 13 32 188 -22 39 38 51 38 44 11 .. .. .. 24 9 52 116 0 0 39 3 52 13 58 20 33 187 -22 39 31 18 38 36 44 .. .. .. 24 3 26 115 0 0 38 56 48 13 58 27 33 186 -21 39 24 12 38 29 43 .. .. .. 23 57 22 114 0 0 38 50 10 13 58 34 33 185 -21 39 17 32 38 23 7 .. .. .. 23 51 40 113 0 0 38 43 57 13 58 42 33 184 -21 39 11 17 38 16 57 .. .. .. 23 46 20 112 0 0 38 38 11 13 58 49 33 182 -20 39 5 29 38 11 13 .. .. .. 23 41 22 111 0 0 38 32 51 13 58 57 33 181 -20 39 0 7 38 5 55 .. .. .. 23 36 47 110 0 0 38 27 58 13 59 4 33 180 -19 38 55 12 38 1 3 .. .. .. 23 32 34 109 0 0 38 23 30 13 59 11 34 179 -19 38 50 43 37 56 37 .. .. .. 23 28 43 108 0 0 38 19 29 13 59 19 34 178 -19 38 46 40 37 52 37 .. .. .. 23 25 16 107 0 0 38 15 54 13 59 26 34 177 -18 38 43 4 37 49 4 .. .. .. 23 22 10 106 0 0 38 12 46 13 59 34 34 176 -18 38 39 55 37 45 56 .. .. .. 23 19 28 105 0 0 38 10 4 13 59 41 34 175 -17 38 37 12 37 43 16 .. .. .. 23 17 8 104 0 0 38 7 49 13 59 49 34 174 -17 38 34 56 37 41 1 .. .. .. 23 15 11 103 0 0 38 6 1 13 59 56 34 172 -16 38 33 7 37 39 14 .. .. .. 23 13 37 102 0 0 38 4 39 14 0 4 33 171 -15 38 31 45 37 37 52 .. .. .. 23 12 25 101 0 0 38 3 44 14 0 11 33 170 -15 38 30 50 37 36 58 .. .. .. 23 11 36 100 0 0 38 3 16 14 0 18 33 169 -14 38 30 22 37 36 29 .. .. .. 23 11 11 99 0 0 38 3 15 14 0 26 33 168 -14 38 30 20 37 36 28 .. .. .. 23 11 8 98 0 0 38 3 40 14 0 33 33 167 -13 38 30 46 37 36 53 .. .. .. 23 11 27 97 0 0 38 4 32 14 0 40 33 166 -13 38 31 38 37 37 45 .. .. .. 23 12 10 96 0 0 38 5 51 14 0 48 32 165 -12 38 32 57 37 39 3 .. .. .. 23 13 16 95 0 0 38 7 36 14 0 55 32 164 -11 38 34 44 37 40 48 .. .. .. 23 14 44 94 0 0 38 9 48 14 1 2 32 163 -11 38 36 57 37 42 59 .. .. .. 23 16 35 93 0 0 38 12 27 14 1 9 32 162 -10 38 39 37 37 45 37 .. .. .. 23 18 50 92 0 0 38 15 33 14 1 16 31 161 -9 38 42 44 37 48 41 .. .. .. 23 21 26 91 0 0 38 19 5 14 1 23 31 160 -9 38 46 17 37 52 12 .. .. .. 23 24 26 90 0 0 38 23 4 14 1 30 31 159 -8 38 50 18 37 56 10 .. .. .. 23 27 49 89 0 0 38 27 30 14 1 37 30 158 -7 38 54 45 38 0 34 .. .. .. 23 31 34 88 0 0 38 32 22 14 1 44 30 157 -7 38 59 39 38 5 24 .. .. .. 23 35 42 87 0 0 38 37 40 14 1 51 30 156 -6 39 4 59 38 10 40 .. .. .. 23 40 12 86 0 0 38 43 25 14 1 57 29 155 -5 39 10 46 38 16 23 .. .. .. 23 45 6 85 0 0 38 49 36 14 2 4 29 154 -5 39 17 0 38 22 32 .. .. .. 23 50 21 84 0 0 38 56 13 14 2 10 28 153 -4 39 23 40 38 29 7 .. .. .. 23 55 59 83 0 0 39 3 17 14 2 17 28 152 -3 39 30 46 38 36 8 .. .. .. 24 2 0 82 0 0 39 10 46 14 2 23 27 151 -2 39 38 18 38 43 34 .. .. .. 24 8 23 81 0 0 39 18 42 14 2 29 27 150 -2 39 46 16 38 51 27 .. .. .. 24 15 8 80 0 0 39 27 3 14 2 35 26 149 -1 39 54 41 38 59 45 .. .. .. 24 22 15 79 0 0 39 35 49 14 2 41 26 148 0 40 3 31 39 8 28 .. .. .. 24 29 44 Uncertainty in time = +/- 120 secs Prediction of 2012 Jun 6.0 Data for the target star ------------------------ * name: UCAC2 24877181 * constellation : Ophiuchus * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 17 16 24.4985 DE: -18 10 22.356 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .176, .176 ) * V mag [mag]: 12.8 * B mag [mag]: 0.0 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (60558) Echeclus approx. diameter [km]: 55 approx. diameter ["]: .011 distance from Earth [AU]: 6.59800 * orbital information: orbit source: Preston date of fit: 2012 Jun 06 source of used astrometry: MPC (via Astdys) number of used observations: 312 number of rejected observations: 20 time covered by the observations: 1979 Sep 23 - 2012 Apr 02 1 sigma uncertainty ellipse (major, minor, PA): 0.225, 0.113, 94° remarks: * orbital elements for (60558) Echeclus : Mean anomaly = 331.72950010 deg Arg. of pericenter = 162.92635406 deg Long. of node = 173.38440746 deg Inclination = 4.34151034 deg Eccentricity = 0.45688879 Semimajor axis = 10.70773103 AU Perihelion dist = 5.81548874 AU Mag: H = 9.32, G = 0.15 Epoch of elements : MJD 56129.57400000 TDT (2012 Jul 21.574) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Jul 21 60558 Echeclus 13h 59.5m UT 12.8 17 16 24.499-18 10 22.36UCAC2 24877181 0.0 18.3 55 4.8 6.598 -0.600 -0.47 109.4825 -18.172 -28.26 20.31 13.9920 -0.04572 0.82978 -6.41856 -0.35382 0.00369 -0.00066 2000 331.4601912012 712.00000162.926354173.384407 4.3415100.4568887910.7077310 5.8154888 9.4 5.00.15 RATE 0.2812920 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.286 0.209 92 20.08 0.219 0 0-5 4 056084.0020120721_877181 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Jun 06, 03:34 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org