IOTA/IOTA-ES occultation update for (1428) Mombasa / TYC 5817-01046-1 event on 2008 May 18, 18:02 UT Visible from Philippines Summary ------- On 2008 May 18 UT, the 57 km diameter asteroid (1428) Mombasa will occult a 11.4 mag star in the constellation Aquarius for observers along a path across Philippines. In the case of an occultation, the combined light of the asteroid and the star will drop by 4.6 mag to 16.0 mag (the magnitude of the asteroid) for at most 2.5 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: 69 * date and approx. time of event: 2008 May 18, 17:58 - 2008 May 18, 18:01 UT * midpoint of event [JD]: 2454605.25187083 * magnitude of target star: 11.4 * magnitude drop [mag]: 4.6 * estimated maximum duration [s]: 2.5 * Moon: 98 % sunlit, 110° distance * Sun: 84° distance * rough path description: Philippines The occultation path -------------------- * approximate projected width [km]: 63 * 1 sigma uncertainty interval [path widths]: +/- 0.86 * 1 sigma uncertainty interval [seconds]: +/- 3.1 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .042 +/- .027) * 1 sigma uncertainty ellipse (major, minor, PA): ( .042", .027", 88° ) * approx speed of asteroid's shadow [km/s]: 22.9103 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 5817-01046-1 by 1428 Mombasa 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 108 0 0 22 26 34 17 58 31 0 106 -44 22 8 47 .. .. .. .. .. .. .. .. .. 109 0 0 22 11 2 17 58 31 1 106 -44 21 53 15 22 28 51 .. .. .. 22 59 37 110 0 0 21 55 33 17 58 31 2 106 -44 21 37 47 22 13 22 21 7 19 22 44 8 111 0 0 21 40 9 17 58 32 3 107 -44 21 22 23 21 57 58 20 51 56 22 28 42 112 0 0 21 24 49 17 58 32 4 107 -43 21 7 4 21 42 38 20 36 38 22 13 21 113 0 0 21 9 35 17 58 32 5 107 -43 20 51 50 21 27 22 20 21 24 21 58 5 114 0 0 20 54 25 17 58 33 6 108 -43 20 36 40 21 12 12 20 6 16 21 42 54 115 0 0 20 39 21 17 58 33 7 108 -43 20 21 37 20 57 7 19 51 13 21 27 48 116 0 0 20 24 22 17 58 34 8 109 -42 20 6 39 20 42 8 19 36 16 21 12 49 117 0 0 20 9 30 17 58 35 9 109 -42 19 51 47 20 27 16 19 21 26 20 57 55 118 0 0 19 54 45 17 58 36 10 109 -42 19 37 2 20 12 29 19 6 41 20 43 8 119 0 0 19 40 6 17 58 37 11 110 -41 19 22 24 19 57 50 18 52 4 20 28 27 120 0 0 19 25 34 17 58 38 12 110 -41 19 7 53 19 43 18 18 37 34 20 13 54 121 0 0 19 11 10 17 58 39 13 110 -40 18 53 30 19 28 53 18 23 12 19 59 28 122 0 0 18 56 54 17 58 40 14 111 -40 18 39 14 19 14 37 18 8 58 19 45 10 123 0 0 18 42 46 17 58 41 15 111 -39 18 25 7 19 0 28 17 54 51 19 31 1 124 0 0 18 28 47 17 58 43 16 111 -39 18 11 8 18 46 28 17 40 54 19 16 59 125 0 0 18 14 56 17 58 44 17 112 -38 17 57 18 18 32 37 17 27 5 19 3 7 126 0 0 18 1 15 17 58 46 18 112 -38 17 43 37 18 18 54 17 13 25 18 49 24 127 0 0 17 47 43 17 58 47 18 112 -37 17 30 6 18 5 22 16 59 55 18 35 50 128 0 0 17 34 20 17 58 49 19 113 -37 17 16 45 17 51 59 16 46 35 18 22 26 129 0 0 17 21 8 17 58 51 20 113 -36 17 3 33 17 38 46 16 33 24 18 9 12 130 0 0 17 8 6 17 58 53 21 114 -36 16 50 32 17 25 43 16 20 25 17 56 8 131 0 0 16 55 15 17 58 55 22 114 -35 16 37 42 17 12 52 16 7 35 17 43 15 132 0 0 16 42 35 17 58 57 23 114 -35 16 25 2 17 0 11 15 54 57 17 30 33 133 0 0 16 30 6 17 58 59 24 115 -34 16 12 34 16 47 41 15 42 30 17 18 2 134 0 0 16 17 49 17 59 1 25 115 -33 16 0 17 16 35 23 15 30 14 17 5 42 135 0 0 16 5 43 17 59 4 26 115 -33 15 48 12 16 23 16 15 18 11 16 53 35 136 0 0 15 53 49 17 59 6 27 116 -32 15 36 19 16 11 22 15 6 19 16 41 39 137 0 0 15 42 8 17 59 8 28 116 -31 15 24 39 15 59 40 14 54 40 16 29 56 138 0 0 15 30 39 17 59 11 29 117 -31 15 13 11 15 48 11 14 43 13 16 18 25 139 0 0 15 19 23 17 59 14 30 117 -30 15 1 55 15 36 54 14 31 59 16 7 7 140 0 0 15 8 21 17 59 16 31 117 -29 14 50 53 15 25 50 14 20 58 15 56 3 141 0 0 14 57 31 17 59 19 32 118 -28 14 40 5 15 15 0 14 10 10 15 45 11 142 0 0 14 46 55 17 59 22 33 118 -28 14 29 29 15 4 24 13 59 36 15 34 33 143 0 0 14 36 33 17 59 25 34 119 -27 14 19 8 14 54 1 13 49 16 15 24 9 144 0 0 14 26 25 17 59 28 35 119 -26 14 9 0 14 43 52 13 39 10 15 13 59 145 0 0 14 16 31 17 59 31 36 120 -26 13 59 7 14 33 58 13 29 18 15 4 4 146 0 0 14 6 52 17 59 34 37 120 -25 13 49 29 14 24 17 13 19 40 14 54 22 147 0 0 13 57 27 17 59 38 38 121 -24 13 40 4 14 14 52 13 10 17 14 44 56 148 0 0 13 48 17 17 59 41 38 121 -23 13 30 55 14 5 42 13 1 9 14 35 44 149 0 0 13 39 22 17 59 44 39 122 -22 13 22 1 13 56 46 12 52 16 14 26 48 150 0 0 13 30 43 17 59 48 40 123 -22 13 13 22 13 48 6 12 43 38 14 18 6 151 0 0 13 22 18 17 59 51 41 123 -21 13 4 58 13 39 41 12 35 15 14 9 40 152 0 0 13 14 10 17 59 55 42 124 -20 12 56 50 13 31 32 12 27 8 14 1 30 153 0 0 13 6 17 17 59 58 43 124 -19 12 48 58 13 23 39 12 19 17 13 53 36 154 0 0 12 58 40 18 0 2 44 125 -18 12 41 22 13 16 1 12 11 42 13 45 58 155 0 0 12 51 20 18 0 6 45 126 -17 12 34 2 13 8 40 12 4 23 13 38 35 156 0 0 12 44 15 18 0 10 46 126 -17 12 26 58 13 1 35 11 57 20 13 31 29 157 0 0 12 37 27 18 0 14 47 127 -16 12 20 10 12 54 46 11 50 33 13 24 40 158 0 0 12 30 56 18 0 18 47 128 -15 12 13 39 12 48 14 11 44 3 13 18 7 159 0 0 12 24 41 18 0 22 48 129 -14 12 7 25 12 41 59 11 37 49 13 11 51 160 0 0 12 18 43 18 0 26 49 130 -13 12 1 27 12 36 1 11 31 53 13 5 52 161 0 0 12 13 2 18 0 30 50 130 -12 11 55 47 12 30 19 11 26 13 13 0 9 162 0 0 12 7 38 18 0 34 51 131 -11 11 50 23 12 24 55 11 20 50 12 54 44 163 0 0 12 2 31 18 0 38 51 132 -11 11 45 17 12 19 47 11 15 44 12 49 36 164 0 0 11 57 41 18 0 42 52 133 -10 11 40 28 12 14 57 11 10 55 12 44 46 165 0 0 11 53 9 18 0 47 53 134 -9 11 35 56 12 10 25 11 6 24 12 40 13 166 0 0 11 48 54 18 0 51 54 135 -8 11 31 41 12 6 10 11 2 10 12 35 57 167 0 0 11 44 57 18 0 55 55 137 -7 11 27 44 12 2 12 10 58 14 12 31 59 168 0 0 11 41 18 18 1 0 55 138 -6 11 24 5 11 58 32 10 54 35 12 28 18 169 0 0 11 37 56 18 1 4 56 139 -5 11 20 44 11 55 10 10 51 14 12 24 56 170 0 0 11 34 52 18 1 9 57 140 -4 11 17 40 11 52 6 10 48 11 12 21 51 171 0 0 11 32 6 18 1 13 57 142 -3 11 14 54 11 49 20 10 45 25 12 19 4 172 0 0 11 29 37 18 1 18 58 143 -2 11 12 26 11 46 51 10 42 57 12 16 36 173 0 0 11 27 27 18 1 22 59 145 -2 11 10 16 11 44 41 10 40 47 12 14 25 174 0 0 11 25 35 18 1 27 59 146 -1 11 8 23 11 42 48 10 38 56 12 12 32 Uncertainty in time = +/- 3 secs [Prediction of 2008 Apr 9.0] Data for the target star ------------------------ * name: TYC 5817-01046-1 * constellation : Aquarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 22 32 48.2629 DE: -14 25 45.715 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .035, .024 ) * V mag [mag]: 11.4 * B mag [mag]: 11.8 * Apparent position with proper motion RA(deg): 338.3148586874 DE(deg): -14.3856672200 * Equation of equinoxes (radians) : 0.000039505925779 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (1428) Mombasa approx. diameter [km]: 57 approx. diameter ["]: .032 distance from Earth [AU]: 2.46200 * orbital information: orbit source: Preston date of fit: 2008 Apr 08 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 631 number of rejected observations: 27 time covered by the observations: 1933 Nov 18 - 2007 Oct 09 1 sigma uncertainty ellipse (major, minor, PA): 0.023, 0.014, 83° remarks: * orbital elements for (1428) Mombasa : Mean anomaly = 317.29165436 deg Arg. of pericenter = 251.00938242 deg Long. of node = 115.85230113 deg Inclination = 17.32776804 deg Eccentricity = 0.13850730 Semimajor axis = 2.81107714 AU Perihelion dist = 2.42172243 AU Mag: H = 10.18, G = 0.15 Epoch of elements : MJD 54604.75200000 TDT (2008 May 18.752) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 May 18 1428 Mombasa 18h 2.7m UT 11.4 22 32 48.263-14 25 45.71TYC 5817-01046-1 11.8 16.0 57 2.5 2.462 3.176 2.30 -169.2638 -14.430 -91.55 19.75 18.0449 -0.02141 0.43670 12.91517 0.64381 -0.00505 -0.00207 2000 316.2979172008 514.00000251.009382115.852301 17.3277680.13850730 2.8110771 2.421722410.9 5.00.15 RATE 2.0911970 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.042 0.027 88 1.86 0.027 0 54565.5020080518_1046-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Apr 13, 03:12 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org