IOTA/IOTA-ES occultation update for (250) Bettina / UCAC2 28124614 event on 2008 May 18, 18:15 UT Visible from New Zealand Summary ------- On 2008 May 18 UT, the 80 km diameter asteroid (250) Bettina will occult a 11.8 mag star in the constellation Aquarius for observers along a path across New Zealand. In the case of an occultation, the combined light of the asteroid and the star will drop by 2.3 mag to 13.9 mag (the magnitude of the asteroid) for at most 2.9 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: 31 * date and approx. time of event: 2008 May 18, 18:11 - 2008 May 18, 18:13 UT * midpoint of event [JD]: 2454605.26050833 * magnitude of target star: 11.8 * magnitude drop [mag]: 2.3 * estimated maximum duration [s]: 2.9 * Moon: 98 % sunlit, 128° distance * Sun: 66° distance * rough path description: New Zealand The occultation path -------------------- * approximate projected width [km]: 88 * 1 sigma uncertainty interval [path widths]: +/- 2.17 * 1 sigma uncertainty interval [seconds]: +/- 5.8 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .063 +/- .065) * 1 sigma uncertainty ellipse (major, minor, PA): ( .065", .063", 359° ) * approx speed of asteroid's shadow [km/s]: 27.9246 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of UCAC2 28124614 by 250 Bettina on 2008 May 18 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 107 0 0 -45 35 27 18 11 40 1 105 -59 -46 0 11 -45 10 49 -47 48 31 .. .. .. 108 0 0 -45 46 44 18 11 41 1 104 -58 -46 11 25 -45 22 8 -47 59 32 .. .. .. 109 0 0 -45 57 40 18 11 41 2 103 -58 -46 22 18 -45 33 7 -48 10 14 .. .. .. 110 0 0 -46 8 16 18 11 41 3 103 -57 -46 32 52 -45 43 45 -48 20 36 .. .. .. 111 0 0 -46 18 32 18 11 41 4 102 -57 -46 43 5 -45 54 4 -48 30 38 .. .. .. 112 0 0 -46 28 28 18 11 41 4 101 -56 -46 52 59 -46 4 3 -48 40 20 .. .. .. 113 0 0 -46 38 4 18 11 41 5 101 -55 -47 2 32 -46 13 41 -48 49 43 .. .. .. 114 0 0 -46 47 21 18 11 42 6 100 -55 -47 11 46 -46 23 0 -48 58 46 .. .. .. 115 0 0 -46 56 17 18 11 42 6 99 -54 -47 20 40 -46 31 59 -49 7 29 .. .. .. 116 0 0 -47 4 54 18 11 42 7 98 -53 -47 29 15 -46 40 38 -49 15 54 -44 56 10 117 0 0 -47 13 11 18 11 43 8 98 -53 -47 37 29 -46 48 57 -49 23 58 -45 4 39 118 0 0 -47 21 8 18 11 43 8 97 -52 -47 45 25 -46 56 56 -49 31 44 -45 12 47 119 0 0 -47 28 46 18 11 44 9 96 -52 -47 53 0 -47 4 36 -49 39 10 -45 20 36 120 0 0 -47 36 4 18 11 44 10 95 -51 -48 0 16 -47 11 56 -49 46 18 -45 28 4 121 0 0 -47 43 3 18 11 45 11 95 -50 -48 7 13 -47 18 57 -49 53 6 -45 35 13 122 0 0 -47 49 42 18 11 45 11 94 -50 -48 13 51 -47 25 38 -49 59 35 -45 42 2 123 0 0 -47 56 2 18 11 46 12 93 -49 -48 20 9 -47 32 0 -50 5 45 -45 48 31 124 0 0 -48 2 3 18 11 46 13 92 -48 -48 26 8 -47 38 2 -50 11 37 -45 54 41 125 0 0 -48 7 44 18 11 47 13 92 -48 -48 31 48 -47 43 45 -50 17 9 -46 0 30 126 0 0 -48 13 6 18 11 48 14 91 -47 -48 37 8 -47 49 9 -50 22 23 -46 6 0 127 0 0 -48 18 9 18 11 49 15 90 -47 -48 42 10 -47 54 13 -50 27 18 -46 11 11 128 0 0 -48 22 53 18 11 49 15 89 -46 -48 46 52 -47 58 58 -50 31 54 -46 16 2 129 0 0 -48 27 18 18 11 50 16 89 -45 -48 51 16 -48 3 24 -50 36 12 -46 20 34 130 0 0 -48 31 23 18 11 51 17 88 -45 -48 55 20 -48 7 31 -50 40 11 -46 24 46 131 0 0 -48 35 10 18 11 52 17 87 -44 -48 59 6 -48 11 19 -50 43 51 -46 28 38 132 0 0 -48 38 38 18 11 53 18 86 -43 -49 2 32 -48 14 48 -50 47 13 -46 32 11 133 0 0 -48 41 47 18 11 54 19 85 -43 -49 5 40 -48 17 58 -50 50 17 -46 35 25 134 0 0 -48 44 37 18 11 55 19 85 -42 -49 8 29 -48 20 48 -50 53 2 -46 38 19 135 0 0 -48 47 7 18 11 56 20 84 -41 -49 10 59 -48 23 20 -50 55 29 -46 40 54 136 0 0 -48 49 20 18 11 57 21 83 -41 -49 13 11 -48 25 33 -50 57 37 -46 43 10 137 0 0 -48 51 13 18 11 58 21 82 -40 -49 15 4 -48 27 27 -50 59 27 -46 45 6 138 0 0 -48 52 47 18 11 59 22 81 -40 -49 16 37 -48 29 2 -51 0 59 -46 46 43 139 0 0 -48 54 3 18 12 0 22 81 -39 -49 17 53 -48 30 18 -51 2 12 -46 48 1 140 0 0 -48 55 0 18 12 1 23 80 -38 -49 18 49 -48 31 15 -51 3 7 -46 49 0 141 0 0 -48 55 38 18 12 2 24 79 -38 -49 19 27 -48 31 53 -51 3 44 -46 49 39 142 0 0 -48 55 57 18 12 3 24 78 -37 -49 19 46 -48 32 12 -51 4 3 -46 49 59 143 0 0 -48 55 57 18 12 4 25 77 -36 -49 19 46 -48 32 13 -51 4 3 -46 49 59 144 0 0 -48 55 39 18 12 6 26 77 -36 -49 19 28 -48 31 54 -51 3 44 -46 49 41 145 0 0 -48 55 1 18 12 7 26 76 -35 -49 18 51 -48 31 17 -51 3 8 -46 49 3 146 0 0 -48 54 5 18 12 8 27 75 -34 -49 17 55 -48 30 20 -51 2 13 -46 48 5 147 0 0 -48 52 50 18 12 10 28 74 -34 -49 16 40 -48 29 5 -51 1 0 -46 46 49 148 0 0 -48 51 16 18 12 11 28 73 -33 -49 15 7 -48 27 31 -50 59 28 -46 45 13 149 0 0 -48 49 24 18 12 12 29 72 -32 -49 13 14 -48 25 37 -50 57 38 -46 43 17 150 0 0 -48 47 12 18 12 14 30 72 -32 -49 11 3 -48 23 25 -50 55 29 -46 41 2 151 0 0 -48 44 41 18 12 15 30 71 -31 -49 8 33 -48 20 54 -50 53 2 -46 38 28 152 0 0 -48 41 51 18 12 17 31 70 -30 -49 5 44 -48 18 3 -50 50 17 -46 35 34 153 0 0 -48 38 43 18 12 18 31 69 -30 -49 2 36 -48 14 54 -50 47 13 -46 32 21 154 0 0 -48 35 15 18 12 20 32 68 -29 -48 59 9 -48 11 25 -50 43 50 -46 28 48 155 0 0 -48 31 28 18 12 21 33 67 -28 -48 55 23 -48 7 37 -50 40 9 -46 24 56 156 0 0 -48 27 21 18 12 23 33 66 -28 -48 51 18 -48 3 29 -50 36 9 -46 20 44 157 0 0 -48 22 56 18 12 25 34 65 -27 -48 46 54 -47 59 3 -50 31 50 -46 16 12 158 0 0 -48 18 11 18 12 26 35 65 -26 -48 42 10 -47 54 17 -50 27 13 -46 11 20 159 0 0 -48 13 7 18 12 28 35 64 -26 -48 37 8 -47 49 11 -50 22 16 -46 6 9 160 0 0 -48 7 44 18 12 30 36 63 -25 -48 31 46 -47 43 46 -50 17 1 -46 0 38 161 0 0 -48 2 1 18 12 32 37 62 -24 -48 26 4 -47 38 2 -50 11 26 -45 54 47 162 0 0 -47 55 58 18 12 33 37 61 -24 -48 20 3 -47 31 57 -50 5 33 -45 48 35 163 0 0 -47 49 36 18 12 35 38 60 -23 -48 13 43 -47 25 34 -49 59 20 -45 42 4 164 0 0 -47 42 54 18 12 37 39 59 -22 -48 7 3 -47 18 50 -49 52 48 -45 35 13 165 0 0 -47 35 53 18 12 39 39 58 -22 -48 0 3 -47 11 46 -49 45 57 -45 28 2 166 0 0 -47 28 31 18 12 41 40 57 -21 -47 52 44 -47 4 23 -49 38 46 -45 20 30 167 0 0 -47 20 50 18 12 43 40 56 -20 -47 45 5 -46 56 40 -49 31 16 -45 12 38 168 0 0 -47 12 49 18 12 45 41 55 -20 -47 37 6 -46 48 36 -49 23 26 -45 4 26 169 0 0 -47 4 27 18 12 47 42 54 -19 -47 28 46 -46 40 13 -49 15 17 -44 55 53 170 0 0 -46 55 46 18 12 49 42 53 -18 -47 20 7 -46 31 29 -49 6 48 -44 47 0 171 0 0 -46 46 44 18 12 51 43 52 -17 -47 11 8 -46 22 25 -48 57 59 -44 37 46 172 0 0 -46 37 22 18 12 53 44 51 -17 -47 1 48 -46 13 1 -48 48 50 -44 28 11 173 0 0 -46 27 40 18 12 55 44 50 -16 -46 52 8 -46 3 16 -48 39 21 -44 18 16 174 0 0 -46 17 37 18 12 58 45 49 -15 -46 42 8 -45 53 11 -48 29 32 -44 8 0 175 0 0 -46 7 14 18 13 0 46 48 -15 -46 31 47 -45 42 45 -48 19 23 -43 57 24 176 0 0 -45 56 30 18 13 2 46 47 -14 -46 21 6 -45 31 58 -48 8 54 -43 46 26 177 0 0 -45 45 25 18 13 4 47 46 -13 -46 10 4 -45 20 51 -47 58 4 -43 35 7 178 0 0 -45 34 0 18 13 7 47 45 -12 -45 58 42 -45 9 23 -47 46 54 -43 23 27 179 0 0 -45 22 14 18 13 9 48 44 -12 -45 46 58 -44 57 34 -47 35 23 -43 11 27 180 0 0 -45 10 7 18 13 12 49 42 -11 -45 34 54 -44 45 24 -47 23 32 -42 59 5 -179 0 0 -44 57 39 18 13 14 49 41 -10 -45 22 29 -44 32 53 -47 11 20 -42 46 21 -178 0 0 -44 44 50 18 13 17 50 40 -9 -45 9 43 -44 20 1 -46 58 47 -42 33 17 -177 0 0 -44 31 40 18 13 19 51 39 -9 -44 56 36 -44 6 48 -46 45 53 -42 19 51 -176 0 0 -44 18 8 18 13 22 51 38 -8 -44 43 8 -43 53 14 -46 32 39 -42 6 5 -175 0 0 -44 4 16 18 13 24 52 36 -7 -44 29 19 -43 39 19 -46 19 4 -41 51 56 -174 0 0 -43 50 3 18 13 27 52 35 -6 -44 15 8 -43 25 2 -46 5 7 -41 37 27 -173 0 0 -43 35 28 18 13 30 53 34 -6 -44 0 37 -43 10 24 -45 50 49 -41 22 36 -172 0 0 -43 20 32 18 13 32 54 32 -5 -43 45 44 -42 55 25 -45 36 11 -41 7 23 -171 0 0 -43 5 15 18 13 35 54 31 -4 -43 30 30 -42 40 5 -45 21 11 -40 51 50 -170 0 0 -42 49 36 18 13 38 55 30 -3 -43 14 55 -42 24 23 -45 5 50 -40 35 54 -169 0 0 -42 33 36 18 13 41 56 28 -3 -42 58 58 -42 8 20 -44 50 8 -40 19 38 -168 0 0 -42 17 15 18 13 44 56 27 -2 -42 42 40 -41 51 56 -44 34 4 -40 3 0 -167 0 0 -42 0 33 18 13 47 57 25 -1 -42 26 1 -41 35 10 -44 17 40 -39 46 1 -166 0 0 -41 43 29 18 13 50 57 24 0 -42 9 1 -41 18 3 -44 0 54 -39 28 41 Uncertainty in time = +/- 6 secs [Prediction of 2008 Apr 13.0] Data for the target star ------------------------ * name: UCAC2 28124614 * constellation : Aquarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 23 47 21.5786 DE: -10 54 22.128 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .061, .065 ) * V mag [mag]: 11.8 * B mag [mag]: 0.0 * Apparent position with proper motion RA(deg): 356.9478353103 DE(deg): -10.8589537143 * Equation of equinoxes (radians) : 0.000039506557885 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (250) Bettina approx. diameter [km]: 80 approx. diameter ["]: .030 distance from Earth [AU]: 3.62400 * orbital information: orbit source: Preston date of fit: 2008 Apr 08 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 649 number of rejected observations: 88 time covered by the observations: 1905 May 02 - 2007 Oct 07 1 sigma uncertainty ellipse (major, minor, PA): 0.014, 0.010, 55° remarks: * orbital elements for (250) Bettina : Mean anomaly = 248.83914818 deg Arg. of pericenter = 75.98687230 deg Long. of node = 23.93129358 deg Inclination = 12.81449052 deg Eccentricity = 0.12944983 Semimajor axis = 3.14640520 AU Perihelion dist = 2.73910359 AU Mag: H = 7.28, G = 0.15 Epoch of elements : MJD 54604.76100000 TDT (2008 May 18.761) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 May 18 250 Bettina 18h 15.1m UT 11.8 23 47 21.579-10 54 22.13UCAC2 28124614 0.0 13.9 80 2.9 3.624 2.413 14.11 -153.7444 -10.910 -94.67 19.75 18.2522 0.15446 -0.38634 14.64925 5.81569 -0.00460 -0.00241 2000 247.9983722008 514.00000 75.986872 23.931294 12.8144910.12944983 3.1464052 2.7391036 7.6 5.00.15 RATE 1.7659650 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.065 0.063 359 3.17 0.065 0 54569.5020080518_124614 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Apr 13, 03:13 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org