IOTA/IOTA-ES occultation update for (149) Medusa / TYC 1878-01212-1 event on 2008 Mar 29, 12:59 UT Visible from Philippines, SE Asia Summary ------- On 2008 Mar 29 UT, the 20 km diameter asteroid (149) Medusa will occult a 10.3 mag star in the constellation Gemini for observers along a path across Philippines, SE Asia. In the case of an occultation, the combined light of the asteroid and the star will drop by 4.8 mag to 15.1 mag (the magnitude of the asteroid) for at most 0.9 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: 46 * date and approx. time of event: 2008 Mar 29, 13:00 - 2008 Mar 29, 13:04 UT * magnitude of target star: 10.3 * magnitude drop [mag]: 4.8 * estimated maximum duration [s]: 0.9 * Moon: 54 % sunlit, 176° distance * Sun: 85° distance * rough path description: Philippines, SE Asia The occultation path -------------------- * approximate projected width [km]: 20 * 1 sigma uncertainty interval [path widths]: +/- 1.41 * 1 sigma uncertainty interval [seconds]: +/- 1.4 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .023 +/- .020) * 1 sigma uncertainty ellipse (major, minor, PA): ( .023", .020", 90° ) * approx speed of asteroid's shadow [km/s]: 20.9751 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 1878-01212-1 by 149 Medusa on 2008 Mar 29 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 78 0 0 16 36 23 13 0 22 82 319 -1 16 30 55 16 41 50 16 15 31 16 57 13 79 0 0 16 33 23 13 0 27 81 315 -2 16 27 55 16 38 50 16 12 31 16 54 14 80 0 0 16 29 58 13 0 33 80 312 -3 16 24 31 16 35 26 16 9 6 16 50 50 81 0 0 16 26 9 13 0 38 79 309 -4 16 20 41 16 31 37 16 5 16 16 47 2 82 0 0 16 21 56 13 0 43 78 306 -5 16 16 28 16 27 24 16 1 2 16 42 49 83 0 0 16 17 18 13 0 48 78 304 -6 16 11 50 16 22 46 15 56 24 16 38 12 84 0 0 16 12 16 13 0 53 77 302 -7 16 6 47 16 17 44 15 51 21 16 33 10 85 0 0 16 6 49 13 0 58 76 301 -8 16 1 20 16 12 18 15 45 53 16 27 44 86 0 0 16 0 58 13 1 3 75 299 -9 15 55 29 16 6 27 15 40 1 16 21 54 87 0 0 15 54 43 13 1 9 74 298 -10 15 49 13 16 0 12 15 33 45 16 15 39 88 0 0 15 48 3 13 1 14 73 297 -11 15 42 33 15 53 32 15 27 4 16 9 1 89 0 0 15 40 59 13 1 19 72 297 -12 15 35 29 15 46 29 15 19 59 16 1 58 90 0 0 15 33 31 13 1 24 71 296 -13 15 28 1 15 39 1 15 12 30 15 54 31 91 0 0 15 25 38 13 1 29 70 295 -14 15 20 8 15 31 9 15 4 36 15 46 39 92 0 0 15 17 22 13 1 34 69 295 -15 15 11 51 15 22 52 14 56 19 15 38 24 93 0 0 15 8 41 13 1 39 68 294 -16 15 3 11 15 14 12 14 47 37 15 29 45 94 0 0 14 59 37 13 1 44 68 294 -17 14 54 6 15 5 8 14 38 31 15 20 42 95 0 0 14 50 9 13 1 48 67 294 -18 14 44 37 14 55 40 14 29 2 15 11 15 96 0 0 14 40 16 13 1 53 66 293 -19 14 34 44 14 45 48 14 19 8 15 1 24 97 0 0 14 30 0 13 1 58 65 293 -20 14 24 28 14 35 33 14 8 51 14 51 9 98 0 0 14 19 21 13 2 3 64 293 -21 14 13 48 14 24 53 13 58 9 14 40 31 99 0 0 14 8 18 13 2 8 63 293 -22 14 2 44 14 13 51 13 47 5 14 29 30 100 0 0 13 56 51 13 2 13 62 292 -23 13 51 17 14 2 24 13 35 37 14 18 5 101 0 0 13 45 1 13 2 17 61 292 -24 13 39 27 13 50 35 13 23 45 14 6 16 102 0 0 13 32 48 13 2 22 60 292 -25 13 27 13 13 38 22 13 11 30 13 54 5 103 0 0 13 20 11 13 2 27 59 292 -26 13 14 36 13 25 46 12 58 52 13 41 30 104 0 0 13 7 12 13 2 31 58 292 -27 13 1 37 13 12 47 12 45 51 13 28 32 105 0 0 12 53 50 13 2 36 57 292 -28 12 48 14 12 59 25 12 32 27 13 15 12 106 0 0 12 40 5 13 2 40 56 292 -29 12 34 29 12 45 41 12 18 40 13 1 28 107 0 0 12 25 57 13 2 45 55 292 -30 12 20 21 12 31 34 12 4 31 12 47 23 108 0 0 12 11 27 13 2 49 54 292 -31 12 5 50 12 17 4 11 49 59 12 32 55 109 0 0 11 56 35 13 2 54 53 292 -32 11 50 58 12 2 13 11 35 5 12 18 4 110 0 0 11 41 21 13 2 58 52 292 -33 11 35 43 11 46 59 11 19 49 12 2 52 111 0 0 11 25 45 13 3 2 51 292 -34 11 20 7 11 31 24 11 4 11 11 47 18 112 0 0 11 9 48 13 3 6 50 292 -35 11 4 8 11 15 27 10 48 12 11 31 22 113 0 0 10 53 29 13 3 11 49 292 -36 10 47 49 10 59 8 10 31 51 11 15 5 114 0 0 10 36 48 13 3 15 48 292 -37 10 31 8 10 42 28 10 15 9 10 58 27 115 0 0 10 19 47 13 3 19 47 292 -38 10 14 7 10 25 28 9 58 6 10 41 28 116 0 0 10 2 26 13 3 23 45 292 -39 9 56 44 10 8 7 9 40 42 10 24 8 117 0 0 9 44 43 13 3 27 44 292 -40 9 39 2 9 50 25 9 22 58 10 6 28 118 0 0 9 26 41 13 3 31 43 293 -41 9 20 59 9 32 23 9 4 54 9 48 27 119 0 0 9 8 19 13 3 34 42 293 -42 9 2 36 9 14 1 8 46 29 9 30 7 120 0 0 8 49 37 13 3 38 41 293 -43 8 43 54 8 55 20 8 27 46 9 11 27 121 0 0 8 30 36 13 3 42 40 293 -44 8 24 52 8 36 19 8 8 43 8 52 28 122 0 0 8 11 16 13 3 45 39 293 -45 8 5 32 8 17 0 7 49 21 8 33 10 123 0 0 7 51 37 13 3 49 38 293 -46 7 45 53 7 57 22 7 29 40 8 13 33 124 0 0 7 31 40 13 3 52 37 293 -47 7 25 55 7 37 26 7 9 42 7 53 38 125 0 0 7 11 26 13 3 56 36 293 -48 7 5 40 7 17 11 6 49 25 7 33 26 126 0 0 6 50 54 13 3 59 35 293 -50 6 45 8 6 56 40 6 28 51 7 12 55 127 0 0 6 30 4 13 4 2 34 293 -51 6 24 18 6 35 51 6 8 0 6 52 8 128 0 0 6 8 58 13 4 5 33 293 -52 6 3 11 6 14 45 5 46 52 6 31 4 129 0 0 5 47 36 13 4 8 32 293 -53 5 41 49 5 53 24 5 25 28 6 9 43 130 0 0 5 25 58 13 4 11 31 293 -54 5 20 10 5 31 46 5 3 49 5 48 7 131 0 0 5 4 5 13 4 14 30 293 -55 4 58 16 5 9 53 4 41 53 5 26 15 132 0 0 4 41 56 13 4 17 29 293 -56 4 36 7 4 47 45 4 19 43 5 4 8 133 0 0 4 19 33 13 4 20 28 293 -57 4 13 44 4 25 23 3 57 19 4 41 47 134 0 0 3 56 57 13 4 22 26 294 -58 3 51 7 4 2 46 3 34 40 4 19 12 135 0 0 3 34 6 13 4 25 25 294 -59 3 28 16 3 39 56 3 11 49 3 56 23 136 0 0 3 11 3 13 4 27 24 294 -60 3 5 12 3 16 53 2 48 44 3 33 21 137 0 0 2 47 47 13 4 30 23 294 -61 2 41 56 2 53 38 2 25 26 3 10 7 138 0 0 2 24 19 13 4 32 22 294 -62 2 18 28 2 30 11 2 1 57 2 46 41 139 0 0 2 0 40 13 4 34 21 294 -63 1 54 49 2 6 32 1 38 17 2 23 3 140 0 0 1 36 50 13 4 36 20 294 -64 1 30 58 1 42 42 1 14 26 1 59 14 141 0 0 1 12 50 13 4 38 19 294 -66 1 6 58 1 18 42 0 50 24 1 35 15 142 0 0 0 48 40 13 4 40 18 294 -67 0 42 47 0 54 33 0 26 13 1 11 6 143 0 0 0 24 21 13 4 41 17 294 -68 0 18 28 0 30 14 0 1 53 0 46 48 144 0 0 - 0 0 7 13 4 43 16 294 -69 - 0 6 0 0 5 46 - 0 22 36 0 22 22 145 0 0 - 0 24 42 13 4 45 15 294 -70 - 0 30 36 - 0 18 49 - 0 47 13 - 0 2 13 146 0 0 - 0 49 25 13 4 46 13 294 -71 - 0 55 19 - 0 43 32 - 1 11 57 - 0 26 55 147 0 0 - 1 14 15 13 4 47 12 294 -72 - 1 20 9 - 1 8 21 - 1 36 47 - 0 51 44 148 0 0 - 1 39 11 13 4 49 11 294 -73 - 1 45 5 - 1 33 17 - 2 1 44 - 1 16 39 149 0 0 - 2 4 12 13 4 50 10 294 -74 - 2 10 6 - 1 58 18 - 2 26 46 - 1 41 39 150 0 0 - 2 29 18 13 4 51 9 294 -75 - 2 35 13 - 2 23 24 - 2 51 53 - 2 6 45 151 0 0 - 2 54 29 13 4 51 8 293 -76 - 3 0 23 - 2 48 34 - 3 17 4 - 2 31 55 152 0 0 - 3 19 43 13 4 52 7 293 -77 - 3 25 37 - 3 13 48 - 3 42 18 - 2 57 8 153 0 0 - 3 45 0 13 4 53 6 293 -78 - 3 50 55 - 3 39 5 - 4 7 36 - 3 22 25 154 0 0 - 4 10 19 13 4 53 5 293 -79 - 4 16 14 - 4 4 24 - 4 32 55 - 3 47 44 155 0 0 - 4 35 40 13 4 54 4 293 -80 - 4 41 35 - 4 29 45 - 4 58 17 - 4 13 5 156 0 0 - 5 1 3 13 4 54 3 293 -81 - 5 6 58 - 4 55 8 - 5 23 39 - 4 38 27 157 0 0 - 5 26 25 13 4 54 2 293 -82 - 5 32 20 - 5 20 30 - 5 49 2 - 5 3 49 158 0 0 - 5 51 48 13 4 54 0 293 -83 - 5 57 43 - 5 45 53 - 6 14 25 - 5 29 12 Uncertainty in time = +/- 2 secs [Prediction of 2008 Mar 13.0] Data for the target star ------------------------ * name: TYC 1878-01212-1 * constellation : Gemini * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 06 17 28.4665 DE: +22 45 33.589 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .016, .017 ) * V mag [mag]: 10.3 * B mag [mag]: 11.5 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (149) Medusa approx. diameter [km]: 20 approx. diameter ["]: .014 distance from Earth [AU]: 1.96100 * orbital information: orbit source: Preston date of fit: 2008 Mar 12 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 685 number of rejected observations: 129 time covered by the observations: 1905 Jan 23 - 2008 Mar 07 1 sigma uncertainty ellipse (major, minor, PA): 0.016, 0.010, 91° remarks: * orbital elements for (149) Medusa : Mean anomaly = 64.33544152 deg Arg. of pericenter = 251.02139552 deg Long. of node = 159.64255826 deg Inclination = 0.93698544 deg Eccentricity = 0.06552782 Semimajor axis = 2.17474084 AU Perihelion dist = 2.03223482 AU Mag: H = 10.41, G = 0.15 Epoch of elements : MJD 54554.54200000 TDT (2008 Mar 29.542) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Mar 29 149 Medusa 12h 59.9m UT 10.3 6 17 28.466 22 45 33.59TYC 1878-01212-1 11.5 15.1 20 0.9 1.961 3.838 -0.39 72.0992 22.759 -13.80 3.65 12.9978 -0.00085 -0.10627 11.83864 -0.08568 0.00539 -0.00017 2000 62.9395882008 325.00000251.021396159.642558 0.9369850.06552782 2.1747408 2.032234810.8 5.00.15 RATE 3.0732140 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.023 0.020 90 2.41 0.020 0 54538.5020080329_1212-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Mar 13, 00:07 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org