IOTA/IOTA-ES occultation update for (176) Iduna / UCAC2 33253929 event on 2012 Aug 22, 04:29 UT Visible from Pacific Ocean Summary ------- On 2012 Aug 22 UT, the 120 km diameter asteroid (176) Iduna will occult a 11.6 mag star in the constellation Ophiuchus for observers along a path across Pacific Ocean. In the case of an occultation, the combined light of the asteroid and the star will drop by 2.0 mag to 13.4 mag (the magnitude of the asteroid) for at most 13.1 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. The event at a glimpse ---------------------- * Rank: 83 * date and approx. time of event: 2012 Aug 22, 04:24 - 2012 Aug 22, 04:40 UT * geocentric midpoint of event [JD]: 2456161.68705417 * magnitude of target star: 11.6 * magnitude drop [mag]: 2.0 * estimated maximum duration [s]: 13.1 * Moon: 25 % sunlit, 65° distance * Sun: 115° distance * rough path description: Pacific Ocean The occultation path -------------------- * approximate projected width [km]: 125 * 1 sigma uncertainty interval [path widths]: +/- 0.63 * 1 sigma uncertainty interval [seconds]: +/- 5.6 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .039 +/- .026) * 1 sigma uncertainty ellipse (major, minor, PA): ( .039", .026", 88° ) * approx speed of asteroid's shadow [km/s]: 9.0918 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of UCAC2 33253929 by 176 Iduna on 2012 Aug 22 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 158 46 40 -78 0 0 4 40 33 0 68 -3 ... .. .. 165 6 27 ... .. .. 171 31 54 167 58 6 -77 0 0 4 40 32 2 59 -4 162 47 59 172 26 4 ... .. .. 177 25 47 174 9 3 -76 0 0 4 40 31 4 53 -5 170 12 33 177 45 12 164 31 27 -178 3 36 178 50 15 -75 0 0 4 40 29 6 49 -6 175 33 34 -178 5 15 171 2 40 -174 26 23 -177 24 32 -74 0 0 4 40 27 7 45 -6 179 44 46 -174 41 58 175 55 5 -171 26 40 -174 18 6 -73 0 0 4 40 25 9 42 -7 -176 50 8 -171 51 55 179 48 12 -168 54 45 -171 40 17 -72 0 0 4 40 22 10 40 -7 -173 58 4 -169 26 55 -176 59 4 -166 44 16 -169 24 27 -71 0 0 4 40 19 11 38 -8 -171 30 53 -167 21 28 -174 15 52 -164 50 47 -167 26 3 -70 0 0 4 40 16 12 36 -8 -169 23 11 -165 31 41 -171 55 15 -163 11 3 -165 41 45 -69 0 0 4 40 13 13 34 -9 -167 31 5 -163 54 41 -169 52 29 -161 42 39 -164 9 6 -68 0 0 4 40 10 15 33 -9 -165 51 47 -162 28 19 -168 4 10 -160 23 43 -162 46 12 -67 0 0 4 40 6 16 32 -9 -164 23 7 -161 10 53 -166 27 46 -159 12 49 -161 31 34 -66 0 0 4 40 2 17 30 -10 -163 3 27 -160 1 3 -165 1 22 -158 8 46 -160 24 0 -65 0 0 4 39 58 18 29 -10 -161 51 26 -158 57 45 -163 43 26 -157 10 37 -159 22 33 -64 0 0 4 39 53 19 29 -10 -160 46 0 -158 0 8 -162 32 47 -156 17 37 -158 26 26 -63 0 0 4 39 49 20 28 -11 -159 46 19 -157 7 27 -161 28 24 -155 29 7 -157 34 59 -62 0 0 4 39 44 21 27 -11 -158 51 40 -156 19 7 -160 29 32 -154 44 35 -156 47 40 -61 0 0 4 39 39 22 27 -11 -158 1 25 -155 34 38 -159 35 28 -154 3 34 -156 4 1 -60 0 0 4 39 34 23 26 -12 -157 15 6 -154 53 34 -158 45 41 -153 25 40 -155 23 37 -59 0 0 4 39 28 24 25 -12 -156 32 16 -154 15 34 -157 59 41 -152 50 35 -154 46 10 -58 0 0 4 39 23 25 25 -12 -155 52 34 -153 40 18 -157 17 4 -152 18 0 -154 11 21 -57 0 0 4 39 17 26 25 -12 -155 15 41 -153 7 30 -156 37 30 -151 47 42 -153 38 55 -56 0 0 4 39 11 27 24 -13 -154 41 20 -152 36 57 -156 0 40 -151 19 27 -153 8 39 -55 0 0 4 39 5 28 24 -13 -154 9 17 -152 8 25 -155 26 20 -150 53 5 -152 40 21 -54 0 0 4 38 59 29 24 -13 -153 39 20 -151 41 45 -154 54 15 -150 28 24 -152 13 51 -53 0 0 4 38 52 30 23 -13 -153 11 18 -151 16 45 -154 24 14 -150 5 17 -151 49 0 -52 0 0 4 38 45 31 23 -14 -152 45 1 -150 53 19 -153 56 6 -149 43 36 -151 25 40 -51 0 0 4 38 38 32 23 -14 -152 20 20 -150 31 19 -153 29 41 -149 23 14 -151 3 44 -50 0 0 4 38 31 33 23 -14 -151 57 8 -150 10 37 -153 4 52 -149 4 5 -150 43 5 -49 0 0 4 38 24 34 23 -14 -151 35 18 -149 51 8 -152 41 30 -148 46 3 -150 23 38 -48 0 0 4 38 17 35 23 -14 -151 14 44 -149 32 47 -152 19 31 -148 29 3 -150 5 17 -47 0 0 4 38 9 36 23 -14 -150 55 20 -149 15 28 -151 58 46 -148 13 1 -149 47 58 -46 0 0 4 38 1 37 23 -15 -150 37 2 -148 59 7 -151 39 12 -147 57 53 -149 31 36 -45 0 0 4 37 53 38 23 -15 -150 19 44 -148 43 41 -151 20 43 -147 43 36 -149 16 9 -44 0 0 4 37 45 39 23 -15 -150 3 24 -148 29 6 -151 3 15 -147 30 5 -149 1 32 -43 0 0 4 37 37 40 23 -15 -149 47 57 -148 15 18 -150 46 44 -147 17 19 -148 47 42 -42 0 0 4 37 29 41 23 -15 -149 33 20 -148 2 15 -150 31 7 -147 5 14 -148 34 36 -41 0 0 4 37 20 42 23 -15 -149 19 30 -147 49 54 -150 16 20 -146 53 48 -148 22 13 -40 0 0 4 37 11 43 23 -15 -149 6 24 -147 38 12 -150 2 20 -146 42 59 -148 10 29 -39 0 0 4 37 3 44 23 -15 -148 54 0 -147 27 8 -149 49 5 -146 32 44 -147 59 23 -38 0 0 4 36 54 45 23 -15 -148 42 15 -147 16 39 -149 36 32 -146 23 2 -147 48 51 -37 0 0 4 36 44 46 24 -15 -148 31 8 -147 6 44 -149 24 38 -146 13 51 -147 38 54 -36 0 0 4 36 35 47 24 -15 -148 20 36 -146 57 20 -149 13 23 -146 5 10 -147 29 28 -35 0 0 4 36 26 48 24 -15 -148 10 38 -146 48 27 -149 2 44 -145 56 57 -147 20 33 -34 0 0 4 36 16 49 25 -16 -148 1 13 -146 40 2 -148 52 38 -145 49 11 -147 12 7 -33 0 0 4 36 7 50 25 -16 -147 52 17 -146 32 5 -148 43 6 -145 41 50 -147 4 9 -32 0 0 4 35 57 51 25 -16 -147 43 51 -146 24 35 -148 34 5 -145 34 53 -146 56 37 -31 0 0 4 35 47 52 26 -16 -147 35 53 -146 17 29 -148 25 33 -145 28 21 -146 49 31 -30 0 0 4 35 37 53 26 -16 -147 28 22 -146 10 48 -148 17 30 -145 22 10 -146 42 50 -29 0 0 4 35 27 54 27 -15 -147 21 17 -146 4 30 -148 9 55 -145 16 22 -146 36 32 -28 0 0 4 35 16 55 27 -15 -147 14 37 -145 58 34 -148 2 46 -145 10 54 -146 30 37 -27 0 0 4 35 6 56 28 -15 -147 8 21 -145 53 0 -147 56 3 -145 5 46 -146 25 4 -26 0 0 4 34 55 56 28 -15 -147 2 27 -145 47 48 -147 49 44 -145 0 58 -146 19 53 -25 0 0 4 34 45 57 29 -15 -146 56 57 -145 42 55 -147 43 50 -144 56 30 -146 15 2 -24 0 0 4 34 34 58 30 -15 -146 51 48 -145 38 22 -147 38 18 -144 52 19 -146 10 31 -23 0 0 4 34 23 59 30 -15 -146 47 1 -145 34 8 -147 33 9 -144 48 26 -146 6 21 -22 0 0 4 34 12 60 31 -15 -146 42 34 -145 30 13 -147 28 22 -144 44 51 -146 2 29 -21 0 0 4 34 1 61 32 -15 -146 38 27 -145 26 37 -147 23 56 -144 41 34 -145 58 56 -20 0 0 4 33 50 62 33 -15 -146 34 40 -145 23 18 -147 19 51 -144 38 32 -145 55 42 -19 0 0 4 33 39 63 34 -15 -146 31 13 -145 20 17 -147 16 7 -144 35 48 -145 52 46 -18 0 0 4 33 28 63 35 -15 -146 28 4 -145 17 33 -147 12 42 -144 33 19 -145 50 7 -17 0 0 4 33 16 64 36 -14 -146 25 14 -145 15 6 -147 9 37 -144 31 7 -145 47 46 -16 0 0 4 33 5 65 38 -14 -146 22 42 -145 12 56 -147 6 52 -144 29 10 -145 45 43 -15 0 0 4 32 53 66 39 -14 -146 20 29 -145 11 2 -147 4 26 -144 27 29 -145 43 56 -14 0 0 4 32 42 66 41 -14 -146 18 33 -145 9 25 -147 2 19 -144 26 3 -145 42 27 -13 0 0 4 32 30 67 42 -14 -146 16 55 -145 8 4 -147 0 30 -144 24 52 -145 41 14 -12 0 0 4 32 18 68 44 -14 -146 15 35 -145 6 59 -146 59 0 -144 23 57 -145 40 18 -11 0 0 4 32 7 69 46 -13 -146 14 32 -145 6 10 -146 57 49 -144 23 17 -145 39 39 -10 0 0 4 31 55 69 48 -13 -146 13 47 -145 5 37 -146 56 56 -144 22 52 -145 39 17 - 9 0 0 4 31 43 70 50 -13 -146 13 19 -145 5 21 -146 56 21 -144 22 42 -145 39 12 - 8 0 0 4 31 31 70 52 -13 -146 13 9 -145 5 20 -146 56 4 -144 22 47 -145 39 23 - 7 0 0 4 31 19 71 54 -13 -146 13 16 -145 5 35 -146 56 6 -144 23 8 -145 39 51 - 6 0 0 4 31 7 72 57 -12 -146 13 41 -145 6 7 -146 56 27 -144 23 44 -145 40 36 - 5 0 0 4 30 55 72 60 -12 -146 14 23 -145 6 54 -146 57 5 -144 24 35 -145 41 38 - 4 0 0 4 30 43 72 62 -12 -146 15 23 -145 7 59 -146 58 3 -144 25 42 -145 42 57 - 3 0 0 4 30 31 73 65 -12 -146 16 41 -145 9 19 -146 59 19 -144 27 4 -145 44 34 - 2 0 0 4 30 19 73 68 -11 -146 18 16 -145 10 57 -147 0 54 -144 28 43 -145 46 28 - 1 0 0 4 30 6 73 72 -11 -146 20 11 -145 12 51 -147 2 48 -144 30 37 -145 48 40 0 0 0 4 29 54 74 75 -11 -146 22 23 -145 15 2 -147 5 1 -144 32 48 -145 51 10 1 0 0 4 29 42 74 78 -10 -146 24 54 -145 17 31 -147 7 34 -144 35 15 -145 53 58 2 0 0 4 29 30 74 82 -10 -146 27 45 -145 20 17 -147 10 27 -144 37 59 -145 57 5 3 0 0 4 29 18 74 85 -10 -146 30 54 -145 23 22 -147 13 40 -144 41 1 -146 0 31 4 0 0 4 29 5 74 89 -9 -146 34 24 -145 26 45 -147 17 13 -144 44 19 -146 4 17 5 0 0 4 28 53 74 92 -9 -146 38 13 -145 30 26 -147 21 8 -144 47 56 -146 8 22 6 0 0 4 28 41 73 95 -9 -146 42 23 -145 34 27 -147 25 24 -144 51 51 -146 12 48 7 0 0 4 28 29 73 98 -8 -146 46 54 -145 38 47 -147 30 2 -144 56 5 -146 17 34 8 0 0 4 28 16 73 102 -8 -146 51 47 -145 43 28 -147 35 3 -145 0 38 -146 22 42 9 0 0 4 28 4 73 105 -8 -146 57 2 -145 48 29 -147 40 26 -145 5 30 -146 28 12 10 0 0 4 27 52 72 107 -7 -147 2 39 -145 53 51 -147 46 13 -145 10 43 -146 34 4 11 0 0 4 27 40 72 110 -7 -147 8 39 -145 59 35 -147 52 25 -145 16 17 -146 40 19 12 0 0 4 27 28 71 113 -7 -147 15 4 -146 5 41 -147 59 1 -145 22 12 -146 46 58 13 0 0 4 27 16 71 115 -6 -147 21 53 -146 12 10 -148 6 3 -145 28 29 -146 54 2 14 0 0 4 27 4 70 117 -6 -147 29 8 -146 19 3 -148 13 31 -145 35 9 -147 1 31 15 0 0 4 26 51 69 119 -5 -147 36 49 -146 26 21 -148 21 27 -145 42 12 -147 9 27 16 0 0 4 26 39 69 121 -5 -147 44 57 -146 34 4 -148 29 51 -145 49 40 -147 17 49 17 0 0 4 26 27 68 123 -5 -147 53 33 -146 42 14 -148 38 44 -145 57 33 -147 26 40 18 0 0 4 26 16 67 125 -4 -148 2 38 -146 50 50 -148 48 8 -146 5 52 -147 36 0 19 0 0 4 26 4 67 127 -4 -148 12 13 -146 59 55 -148 58 3 -146 14 38 -147 45 51 20 0 0 4 25 52 66 128 -3 -148 22 20 -147 9 29 -149 8 30 -146 23 52 -147 56 12 21 0 0 4 25 40 65 129 -3 -148 32 59 -147 19 34 -149 19 31 -146 33 35 -148 7 7 22 0 0 4 25 28 64 131 -3 -148 44 12 -147 30 11 -149 31 8 -146 43 49 -148 18 36 23 0 0 4 25 17 63 132 -2 -148 56 0 -147 41 20 -149 43 21 -146 54 35 -148 30 40 24 0 0 4 25 5 63 133 -2 -149 8 25 -147 53 4 -149 56 13 -147 5 53 -148 43 22 25 0 0 4 24 54 62 134 -1 -149 21 29 -148 5 24 -150 9 45 -147 17 46 -148 56 42 26 0 0 4 24 42 61 135 -1 -149 35 12 -148 18 21 -150 23 58 -147 30 15 -149 10 43 27 0 0 4 24 31 60 135 0 -149 49 38 -148 31 58 -150 38 55 -147 43 22 Uncertainty in time = +/- 8 secs Prediction of 2012 Jul 21.0 Data for the target star ------------------------ * name: UCAC2 33253929 * constellation : Ophiuchus * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 17 53 04.3291 DE: +04 13 46.879 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .036, .025 ) * V mag [mag]: 11.6 * B mag [mag]: 0.0 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (176) Iduna approx. diameter [km]: 120 approx. diameter ["]: .062 distance from Earth [AU]: 2.64800 * orbital information: orbit source: Preston date of fit: 2012 Jul 21 source of used astrometry: FASTT TMO MPC (via Astdys) number of used observations: 1087 number of rejected observations: 66 time covered by the observations: 1900 Nov 11 - 2012 Jul 19 1 sigma uncertainty ellipse (major, minor, PA): 0.016, 0.009, 78° remarks: * orbital elements for (176) Iduna : Mean anomaly = 276.90013427 deg Arg. of pericenter = 187.26752186 deg Long. of node = 200.68946549 deg Inclination = 22.58652248 deg Eccentricity = 0.16602301 Semimajor axis = 3.18766930 AU Perihelion dist = 2.65844286 AU Mag: H = 8.18, G = 0.15 Epoch of elements : MJD 56161.18700000 TDT (2012 Aug 22.187) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Aug 22 176 Iduna 4h 29.4m UT 11.6 17 53 4.329 4 13 46.88UCAC2 33253929 0.0 13.4 120 13.1 2.648 0.100 -16.98 -129.9609 4.234 113.38 11.65 4.4893 -0.27763 -0.02443 0.44637 -5.11221 0.00502 -0.00133 2000 276.6945712012 821.00000187.267522200.689465 22.5865220.16602301 3.1876693 2.6584428 7.9 5.00.15 RATE 1.7317860 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.039 0.026 88 1.63 0.039 0 0 1-1 056129.0020120822_253929 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Jul 21, 14:41 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org