IOTA/IOTA-ES occultation update for (106) Dione / 2UCAC 21847138 event on 2008 Apr 01, 06:28 UT Visible from Caribbean Summary ------- On 2008 Apr 01 UT, the 147 km diameter asteroid (106) Dione will occult a 12.0 mag star in the constellation Sagittarius for observers along a path across Caribbean. In the case of an occultation, the combined light of the asteroid and the star will drop by 1.8 mag to 13.6 mag (the magnitude of the asteroid) for at most 12.5 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. The event at a glimpse ---------------------- * Rank: 63 * date and approx. time of event: 2008 Apr 01, 06:20 - 2008 Apr 01, 06:28 UT * magnitude of target star: 12.0 * magnitude drop [mag]: 1.8 * estimated maximum duration [s]: 12.5 * Moon: 27 % sunlit, 35° distance * Sun: 97° distance * rough path description: Caribbean The occultation path -------------------- * approximate projected width [km]: 159 * 1 sigma uncertainty interval [path widths]: +/- 0.96 * 1 sigma uncertainty interval [seconds]: +/- 6.8 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .037 +/- .061) * 1 sigma uncertainty ellipse (major, minor, PA): ( .061", .037", 0° ) * approx speed of asteroid's shadow [km/s]: 11.7533 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of 2UCAC 21847138 by 106 Dione on 2008 Apr 1 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 - 87 0 0 26 0 54 6 20 0 0 118 -59 25 12 46 .. .. .. 23 41 9 .. .. .. - 86 0 0 25 32 20 6 20 0 1 118 -59 24 44 12 26 20 47 23 12 33 .. .. .. - 85 0 0 25 3 37 6 20 1 2 119 -59 24 15 28 25 52 5 22 43 48 27 26 0 - 84 0 0 24 34 46 6 20 1 3 119 -59 23 46 36 25 23 14 22 14 55 26 57 10 - 83 0 0 24 5 47 6 20 2 4 119 -59 23 17 37 24 54 15 21 45 54 26 28 12 - 82 0 0 23 36 41 6 20 3 5 120 -59 22 48 31 24 25 9 21 16 48 25 59 6 - 81 0 0 23 7 28 6 20 4 6 120 -59 22 19 18 23 55 56 20 47 35 25 29 54 - 80 0 0 22 38 10 6 20 5 7 121 -59 21 50 0 23 26 38 20 18 18 25 0 35 - 79 0 0 22 8 48 6 20 6 8 121 -59 21 20 38 22 57 15 19 48 57 24 31 10 - 78 0 0 21 39 21 6 20 8 9 121 -59 20 51 12 22 27 47 19 19 33 24 1 41 - 77 0 0 21 9 51 6 20 10 10 122 -59 20 21 43 21 58 16 18 50 6 23 32 8 - 76 0 0 20 40 19 6 20 12 11 122 -59 19 52 13 21 28 43 18 20 37 23 2 32 - 75 0 0 20 10 46 6 20 14 13 122 -59 19 22 41 20 59 8 17 51 8 22 32 54 - 74 0 0 19 41 11 6 20 17 14 123 -59 18 53 8 20 29 32 17 21 39 22 3 15 - 73 0 0 19 11 38 6 20 19 15 123 -58 18 23 37 19 59 57 16 52 11 21 33 35 - 72 0 0 18 42 5 6 20 22 16 124 -58 17 54 6 19 30 22 16 22 44 21 3 56 - 71 0 0 18 12 35 6 20 25 17 124 -58 17 24 38 19 0 49 15 53 21 20 34 19 - 70 0 0 17 43 7 6 20 28 18 124 -57 16 55 13 18 31 19 15 24 1 20 4 43 - 69 0 0 17 13 43 6 20 32 19 125 -57 16 25 52 18 1 52 14 54 45 19 35 11 - 68 0 0 16 44 24 6 20 36 20 125 -56 15 56 36 17 32 30 14 25 34 19 5 43 - 67 0 0 16 15 11 6 20 40 21 125 -56 15 27 26 17 3 13 13 56 30 18 36 20 - 66 0 0 15 46 4 6 20 44 22 126 -55 14 58 22 16 34 3 13 27 33 18 7 2 - 65 0 0 15 17 4 6 20 48 23 126 -55 14 29 26 16 4 59 12 58 43 17 37 51 - 64 0 0 14 48 12 6 20 52 24 126 -54 14 0 38 15 36 4 12 30 2 17 8 48 - 63 0 0 14 19 29 6 20 57 25 127 -54 13 31 59 15 7 17 12 1 31 16 39 54 - 62 0 0 13 50 56 6 21 2 26 127 -53 13 3 30 14 38 40 11 33 10 16 11 8 - 61 0 0 13 22 34 6 21 7 28 127 -52 12 35 12 14 10 13 11 5 0 15 42 33 - 60 0 0 12 54 24 6 21 12 29 128 -52 12 7 6 13 41 58 10 37 2 15 14 9 - 59 0 0 12 26 26 6 21 18 30 128 -51 11 39 13 13 13 55 10 9 17 14 45 57 - 58 0 0 11 58 41 6 21 24 31 129 -50 11 11 32 12 46 6 9 41 46 14 17 58 - 57 0 0 11 31 9 6 21 29 32 129 -49 10 44 6 12 18 30 9 14 29 13 50 12 - 56 0 0 11 3 53 6 21 35 33 129 -49 10 16 55 11 51 8 8 47 27 13 22 41 - 55 0 0 10 36 52 6 21 42 34 130 -48 9 49 59 11 24 2 8 20 41 12 55 25 - 54 0 0 10 10 8 6 21 48 35 130 -47 9 23 20 10 57 12 7 54 11 12 28 24 - 53 0 0 9 43 40 6 21 55 36 130 -46 8 56 57 10 30 39 7 27 59 12 1 41 - 52 0 0 9 17 30 6 22 1 37 131 -45 8 30 53 10 4 24 7 2 5 11 35 15 - 51 0 0 8 51 39 6 22 8 38 131 -45 8 5 7 9 38 27 6 36 29 11 9 7 - 50 0 0 8 26 6 6 22 15 39 132 -44 7 39 40 9 12 49 6 11 13 10 43 17 - 49 0 0 8 0 54 6 22 22 40 132 -43 7 14 33 8 47 30 5 46 17 10 17 48 - 48 0 0 7 36 2 6 22 30 41 133 -42 6 49 47 8 22 32 5 21 41 9 52 38 - 47 0 0 7 11 30 6 22 37 42 133 -41 6 25 21 7 57 55 4 57 26 9 27 50 - 46 0 0 6 47 21 6 22 45 43 134 -40 6 1 17 7 33 40 4 33 33 9 3 23 - 45 0 0 6 23 33 6 22 53 44 134 -39 5 37 36 7 9 47 4 10 3 8 39 18 - 44 0 0 6 0 9 6 23 1 45 135 -38 5 14 17 6 46 16 3 46 55 8 15 36 - 43 0 0 5 37 7 6 23 9 46 135 -37 4 51 22 6 23 9 3 24 10 7 52 17 - 42 0 0 5 14 30 6 23 17 47 136 -36 4 28 50 6 0 25 3 1 50 7 29 22 - 41 0 0 4 52 17 6 23 25 48 137 -35 4 6 43 5 38 6 2 39 54 7 6 51 - 40 0 0 4 30 28 6 23 33 49 137 -34 3 45 0 5 16 12 2 18 22 6 44 45 - 39 0 0 4 9 5 6 23 42 50 138 -33 3 23 43 4 54 43 1 57 16 6 23 4 - 38 0 0 3 48 8 6 23 51 51 139 -32 3 2 51 4 33 39 1 36 35 6 1 49 - 37 0 0 3 27 36 6 23 59 52 139 -31 2 42 25 4 13 2 1 16 20 5 41 0 - 36 0 0 3 7 31 6 24 8 53 140 -30 2 22 26 3 52 51 0 56 32 5 20 38 - 35 0 0 2 47 53 6 24 17 54 141 -29 2 2 54 3 33 8 0 37 10 5 0 43 - 34 0 0 2 28 43 6 24 26 55 142 -28 1 43 49 3 13 51 0 18 16 4 41 16 - 33 0 0 2 10 0 6 24 35 56 143 -27 1 25 11 2 55 3 - 0 0 11 4 22 16 - 32 0 0 1 51 44 6 24 44 57 144 -26 1 7 2 2 36 42 - 0 18 10 4 3 44 - 31 0 0 1 33 58 6 24 54 57 145 -25 0 49 20 2 18 49 - 0 35 42 3 45 41 - 30 0 0 1 16 39 6 25 3 58 146 -24 0 32 7 2 1 26 - 0 52 45 3 28 7 - 29 0 0 0 59 49 6 25 12 59 147 -23 0 15 23 1 44 31 - 1 9 19 3 11 1 - 28 0 0 0 43 29 6 25 22 60 149 -22 - 0 0 53 1 28 5 - 1 25 25 2 54 25 - 27 0 0 0 27 38 6 25 31 61 150 -21 - 0 16 39 1 12 8 - 1 41 2 2 38 19 - 26 0 0 0 12 16 6 25 41 61 151 -20 - 0 31 56 0 56 42 - 1 56 10 2 22 42 - 25 0 0 - 0 2 36 6 25 50 62 153 -19 - 0 46 43 0 41 45 - 2 10 48 2 7 36 - 24 0 0 - 0 16 58 6 26 0 63 154 -18 - 1 1 1 0 27 18 - 2 24 57 1 53 0 - 23 0 0 - 0 30 50 6 26 10 63 156 -17 - 1 14 48 0 13 21 - 2 38 35 1 38 54 - 22 0 0 - 0 44 12 6 26 20 64 158 -16 - 1 28 5 - 0 0 5 - 2 51 44 1 25 19 - 21 0 0 - 0 57 3 6 26 29 65 160 -15 - 1 40 52 - 0 13 1 - 3 4 23 1 12 15 - 20 0 0 - 1 9 24 6 26 39 65 162 -14 - 1 53 9 - 0 25 26 - 3 16 32 0 59 42 - 19 0 0 - 1 21 14 6 26 49 66 164 -13 - 2 4 55 - 0 37 20 - 3 28 10 0 47 40 - 18 0 0 - 1 32 33 6 26 59 66 166 -12 - 2 16 10 - 0 48 43 - 3 39 18 0 36 9 - 17 0 0 - 1 43 21 6 27 9 66 168 -11 - 2 26 55 - 0 59 34 - 3 49 56 0 25 10 - 16 0 0 - 1 53 38 6 27 19 67 170 -10 - 2 37 8 - 1 9 55 - 4 0 3 0 14 42 - 15 0 0 - 2 3 24 6 27 28 67 172 -9 - 2 46 51 - 1 19 44 - 4 9 39 0 4 46 - 14 0 0 - 2 12 39 6 27 38 67 175 -8 - 2 56 2 - 1 29 2 - 4 18 44 - 0 4 38 - 13 0 0 - 2 21 22 6 27 48 68 177 -7 - 3 4 42 - 1 37 49 - 4 27 19 - 0 13 31 - 12 0 0 - 2 29 34 6 27 58 68 180 -6 - 3 12 51 - 1 46 3 - 4 35 22 - 0 21 51 - 11 0 0 - 2 37 14 6 28 8 68 182 -5 - 3 20 29 - 1 53 47 - 4 42 55 - 0 29 40 - 10 0 0 - 2 44 23 6 28 18 68 185 -4 - 3 27 35 - 2 0 58 - 4 49 56 - 0 36 56 - 9 0 0 - 2 51 1 6 28 28 68 187 -3 - 3 34 10 - 2 7 38 - 4 56 27 - 0 43 41 - 8 0 0 - 2 57 6 6 28 38 68 190 -2 - 3 40 13 - 2 13 46 - 5 2 26 - 0 49 53 - 7 0 0 - 3 2 40 6 28 48 68 192 -1 - 3 45 45 - 2 19 22 - 5 7 54 - 0 55 33 Uncertainty in time = +/- 12 secs [Prediction of 2008 Mar 28.0] Data for the target star ------------------------ * name: 2UCAC 21847138 * constellation : Sagittarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 18 19 45.0390 DE: -24 42 34.132 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .035, .060 ) * V mag [mag]: 12.0 * B mag [mag]: 0.0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (106) Dione approx. diameter [km]: 147 approx. diameter ["]: .063 distance from Earth [AU]: 3.22500 * orbital information: orbit source: Preston date of fit: 2008 Mar 27 source of used astrometry: FASTT TMO MPC (via Astdys) number of used observations: 779 number of rejected observations: 154 time covered by the observations: 1900 May 01 - 2008 Mar 25 1 sigma uncertainty ellipse (major, minor, PA): 0.014, 0.010, 92° remarks: * orbital elements for (106) Dione : Mean anomaly = 241.98419786 deg Arg. of pericenter = 329.24295153 deg Long. of node = 62.40363623 deg Inclination = 4.61020235 deg Eccentricity = 0.17160616 Semimajor axis = 3.17492565 AU Perihelion dist = 2.63008886 AU Mag: H = 7.46, G = 0.15 Epoch of elements : MJD 54557.27000000 TDT (2008 Apr 01.270) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Apr 1 106 Dione 6h 28.4m UT 12.0 18 19 45.039-24 42 34.132UCAC 21847138 0.0 13.6 147 12.5 3.225 1.318 -2.09 -12.1513 -24.709 83.86 4.71 6.4732 0.04483 0.37296 6.58947 -0.76619 -0.00586 -0.00018 2000 240.7176022008 325.00000329.242952 62.403636 4.6102020.17160616 3.1749257 2.6300889 7.4 5.00.15 RATE 1.7422230 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.061 0.037 0 1.96 0.060 0 54553.5020080401_847138 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Mar 28, 06:17 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org