IOTA/IOTA-ES occultation update for (850) Altona / 2UCAC 37127360 event on 2008 Apr 03, 03:00 UT Visible from Mexico Summary ------- On 2008 Apr 03 UT, the 81 km diameter asteroid (850) Altona will occult a 12.4 mag star in the constellation Orion for observers along a path across Mexico. In the case of an occultation, the combined light of the asteroid and the star will drop by 3.5 mag to 15.9 mag (the magnitude of the asteroid) for at most 2.8 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: 38 * date and approx. time of event: 2008 Apr 03, 03:05 - 2008 Apr 03, 03:06 UT * magnitude of target star: 12.4 * magnitude drop [mag]: 3.5 * estimated maximum duration [s]: 2.8 * Moon: 12 % sunlit, 102° distance * Sun: 61° distance * rough path description: Mexico Additional comments ------------------- dim star The occultation path -------------------- * approximate projected width [km]: 81 * 1 sigma uncertainty interval [path widths]: +/- 1.75 * 1 sigma uncertainty interval [seconds]: +/- 4.9 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .055 +/- .052) * 1 sigma uncertainty ellipse (major, minor, PA): ( .055", .052", 89° ) * approx speed of asteroid's shadow [km/s]: 29.0330 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of 2UCAC 37127360 by 850 Altona on 2008 Apr 3 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 -133 0 0 21 58 43 3 5 9 60 262 0 21 36 30 22 20 56 20 18 43 23 38 40 -132 0 0 22 7 16 3 5 12 59 263 -1 21 45 4 22 29 27 20 27 22 23 47 7 -131 0 0 22 15 25 3 5 16 58 263 -2 21 53 15 22 37 35 20 35 37 23 55 9 -130 0 0 22 23 9 3 5 19 57 263 -3 22 1 0 22 45 18 20 43 28 24 2 48 -129 0 0 22 30 30 3 5 22 56 264 -4 22 8 22 22 52 37 20 50 53 24 10 2 -128 0 0 22 37 26 3 5 25 55 264 -5 22 15 19 22 59 32 20 57 55 24 16 53 -127 0 0 22 43 57 3 5 28 54 265 -6 22 21 52 23 6 2 21 4 32 24 23 20 -126 0 0 22 50 5 3 5 30 53 265 -7 22 28 0 23 12 9 21 10 44 24 29 22 -125 0 0 22 55 48 3 5 33 52 265 -8 22 33 45 23 17 51 21 16 31 24 35 1 -124 0 0 23 1 7 3 5 36 51 266 -8 22 39 4 23 23 9 21 21 54 24 40 16 -123 0 0 23 6 1 3 5 39 51 266 -9 22 44 0 23 28 3 21 26 53 24 45 7 -122 0 0 23 10 32 3 5 42 50 266 -10 22 48 31 23 32 32 21 31 27 24 49 34 -121 0 0 23 14 38 3 5 44 49 267 -11 22 52 38 23 36 38 21 35 36 24 53 36 -120 0 0 23 18 20 3 5 47 48 267 -12 22 56 20 23 40 19 21 39 21 24 57 15 -119 0 0 23 21 37 3 5 50 47 268 -13 22 59 39 23 43 36 21 42 41 25 0 31 -118 0 0 23 24 31 3 5 52 46 268 -14 23 2 33 23 46 29 21 45 37 25 3 22 -117 0 0 23 27 0 3 5 55 45 268 -15 23 5 2 23 48 58 21 48 8 25 5 49 -116 0 0 23 29 5 3 5 57 44 269 -16 23 7 8 23 51 2 21 50 15 25 7 52 -115 0 0 23 30 46 3 6 0 43 269 -17 23 8 49 23 52 43 21 51 57 25 9 32 -114 0 0 23 32 3 3 6 2 42 270 -17 23 10 6 23 54 0 21 53 15 25 10 48 -113 0 0 23 32 55 3 6 5 41 270 -18 23 10 59 23 54 52 21 54 8 25 11 40 -112 0 0 23 33 24 3 6 7 40 270 -19 23 11 27 23 55 20 21 54 37 25 12 8 -111 0 0 23 33 28 3 6 9 39 271 -20 23 11 31 23 55 25 21 54 41 25 12 12 -110 0 0 23 33 8 3 6 11 38 271 -21 23 11 12 23 55 5 21 54 21 25 11 52 -109 0 0 23 32 24 3 6 14 38 271 -22 23 10 28 23 54 21 21 53 37 25 11 9 -108 0 0 23 31 16 3 6 16 37 272 -23 23 9 19 23 53 13 21 52 28 25 10 2 -107 0 0 23 29 44 3 6 18 36 272 -24 23 7 47 23 51 41 21 50 55 25 8 31 -106 0 0 23 27 48 3 6 20 35 273 -25 23 5 51 23 49 46 21 48 57 25 6 37 -105 0 0 23 25 28 3 6 22 34 273 -25 23 3 30 23 47 26 21 46 35 25 4 18 -104 0 0 23 22 44 3 6 24 33 273 -26 23 0 45 23 44 42 21 43 49 25 1 36 -103 0 0 23 19 36 3 6 26 32 274 -27 22 57 37 23 41 35 21 40 38 24 58 30 -102 0 0 23 16 3 3 6 28 31 274 -28 22 54 4 23 38 3 21 37 3 24 55 1 -101 0 0 23 12 7 3 6 29 30 275 -29 22 50 7 23 34 8 21 33 4 24 51 8 -100 0 0 23 7 47 3 6 31 29 275 -30 22 45 46 23 29 48 21 28 40 24 46 51 - 99 0 0 23 3 3 3 6 33 28 275 -31 22 41 1 23 25 5 21 23 53 24 42 11 - 98 0 0 22 57 55 3 6 35 27 276 -32 22 35 52 23 19 58 21 18 41 24 37 7 - 97 0 0 22 52 23 3 6 36 26 276 -33 22 30 19 23 14 27 21 13 5 24 31 39 - 96 0 0 22 46 27 3 6 38 25 277 -34 22 24 23 23 8 32 21 7 4 24 25 48 - 95 0 0 22 40 8 3 6 39 25 277 -34 22 18 2 23 2 13 21 0 40 24 19 33 - 94 0 0 22 33 24 3 6 41 24 277 -35 22 11 17 22 55 31 20 53 51 24 12 54 - 93 0 0 22 26 17 3 6 42 23 278 -36 22 4 9 22 48 25 20 46 39 24 5 52 - 92 0 0 22 18 46 3 6 43 22 278 -37 21 56 36 22 40 55 20 39 2 23 58 27 - 91 0 0 22 10 51 3 6 45 21 278 -38 21 48 40 22 33 1 20 31 1 23 50 38 - 90 0 0 22 2 32 3 6 46 20 279 -39 21 40 20 22 24 44 20 22 37 23 42 25 - 89 0 0 21 53 50 3 6 47 19 279 -40 21 31 37 22 16 3 20 13 48 23 33 50 - 88 0 0 21 44 44 3 6 48 18 280 -41 21 22 29 22 6 59 20 4 35 23 24 50 - 87 0 0 21 35 15 3 6 49 17 280 -42 21 12 58 21 57 31 19 54 59 23 15 28 - 86 0 0 21 25 22 3 6 51 16 280 -42 21 3 4 21 47 39 19 44 59 23 5 42 - 85 0 0 21 15 5 3 6 51 15 281 -43 20 52 45 21 37 25 19 34 35 22 55 32 - 84 0 0 21 4 25 3 6 52 14 281 -44 20 42 4 21 26 46 19 23 48 22 45 0 - 83 0 0 20 53 22 3 6 53 13 281 -45 20 30 59 21 15 45 19 12 37 22 34 4 - 82 0 0 20 41 55 3 6 54 12 282 -46 20 19 30 21 4 20 19 1 2 22 22 46 - 81 0 0 20 30 5 3 6 55 11 282 -47 20 7 39 20 52 31 18 49 4 22 11 4 - 80 0 0 20 17 52 3 6 56 10 282 -48 19 55 24 20 40 20 18 36 42 21 58 59 - 79 0 0 20 5 16 3 6 56 9 283 -49 19 42 45 20 27 46 18 23 58 21 46 31 - 78 0 0 19 52 17 3 6 57 8 283 -50 19 29 44 20 14 49 18 10 50 21 33 41 - 77 0 0 19 38 54 3 6 57 7 283 -51 19 16 20 20 1 28 17 57 19 21 20 28 - 76 0 0 19 25 10 3 6 58 6 284 -51 19 2 33 19 47 46 17 43 25 21 6 52 - 75 0 0 19 11 2 3 6 58 5 284 -52 18 48 24 19 33 40 17 29 8 20 52 53 - 74 0 0 18 56 32 3 6 58 5 284 -53 18 33 52 19 19 12 17 14 29 20 38 32 - 73 0 0 18 41 39 3 6 59 4 285 -54 18 18 57 19 4 21 16 59 27 20 23 49 - 72 0 0 18 26 24 3 6 59 3 285 -55 18 3 40 18 49 8 16 44 3 20 8 43 - 71 0 0 18 10 47 3 6 59 2 285 -56 17 48 1 18 33 33 16 28 16 19 53 16 - 70 0 0 17 54 48 3 6 59 1 286 -57 17 31 59 18 17 36 16 12 7 19 37 26 Uncertainty in time = +/- 5 secs [Prediction of 2008 Mar 28.0] Data for the target star ------------------------ * name: 2UCAC 37127360 * constellation : Orion * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 04 56 21.8242 DE: +15 07 09.515 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .053, .052 ) * V mag [mag]: 12.4 * B mag [mag]: 0.0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (850) Altona approx. diameter [km]: 81 approx. diameter ["]: .030 distance from Earth [AU]: 3.72700 * orbital information: orbit source: Preston date of fit: 2008 Mar 27 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 703 number of rejected observations: 59 time covered by the observations: 1917 Jul 28 - 2008 Feb 11 1 sigma uncertainty ellipse (major, minor, PA): 0.015, 0.009, 70° remarks: * orbital elements for (850) Altona : Mean anomaly = 200.88263131 deg Arg. of pericenter = 130.95245417 deg Long. of node = 121.47065315 deg Inclination = 15.48490612 deg Eccentricity = 0.12700739 Semimajor axis = 3.00037938 AU Perihelion dist = 2.61930903 AU Mag: H = 9.62, G = 0.15 Epoch of elements : MJD 54559.12500000 TDT (2008 Apr 03.125) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Apr 3 850 Altona 3h 3.3m UT 12.4 4 56 21.824 15 7 9.522UCAC 37127360 0.0 15.9 81 2.8 3.727 2.525 12.58 -163.5632 15.116 134.99 5.42 3.0554 0.00364 -0.01161 15.49422 5.33513 0.00517 0.00020 2000 199.1521272008 325.00000130.952454121.470653 15.4849060.12700739 3.0003794 2.6193090 9.6 5.00.15 RATE 1.8964430 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.055 0.052 89 2.75 0.052 0 54553.5020080403_127360 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Mar 28, 06:31 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org