IOTA/IOTA-ES occultation update for (850) Altona / UCAC2 36945116 event on 2008 Mar 27, 08:56 UT Visible from NE Australia Summary ------- On 2008 Mar 27 UT, the 81 km diameter asteroid (850) Altona will occult a 11.7 mag star in the constellation Orion for observers along a path across NE Australia. In the case of an occultation, the combined light of the asteroid and the star will drop by 4.2 mag to 15.9 mag (the magnitude of the asteroid) for at most 3.0 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: 41 * date and approx. time of event: 2008 Mar 27, 08:56 - 2008 Mar 27, 08:59 UT * midpoint of event [JD]: 2454552.87238333 * magnitude of target star: 11.7 * magnitude drop [mag]: 4.2 * estimated maximum duration [s]: 3.0 * Moon: 73 % sunlit, 167° distance * Sun: 66° distance * rough path description: NE Australia The occultation path -------------------- * approximate projected width [km]: 111 * 1 sigma uncertainty interval [path widths]: +/- 1.62 * 1 sigma uncertainty interval [seconds]: +/- 4.7 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .049 +/- .050) * 1 sigma uncertainty ellipse (major, minor, PA): ( .050", .049", 359° ) * approx speed of asteroid's shadow [km/s]: 26.7879 * website for maps: http://lunar-occultations.com/iota/asteroids/astrndx.htm http://www.asteroidoccultation.com Path Coordinates: Occultation of UCAC2 36945116 by 850 Altona on 2008 Mar 27 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 136 0 0 -23 25 19 8 56 41 46 327 0 -23 57 32 -22 53 24 -25 44 6 -21 11 55 137 0 0 -23 5 35 8 56 45 46 326 -1 -23 37 41 -22 33 46 -25 23 53 -20 52 35 138 0 0 -22 46 23 8 56 50 46 325 -2 -23 18 23 -22 14 40 -25 4 13 -20 33 48 139 0 0 -22 27 44 8 56 54 45 323 -3 -22 59 38 -21 56 7 -24 45 7 -20 15 33 140 0 0 -22 9 38 8 56 58 45 322 -4 -22 41 26 -21 38 6 -24 26 34 -19 57 50 141 0 0 -21 52 5 8 57 1 45 321 -5 -22 23 48 -21 20 40 -24 8 36 -19 40 40 142 0 0 -21 35 6 8 57 5 44 319 -6 -22 6 43 -21 3 46 -23 51 13 -19 24 4 143 0 0 -21 18 42 8 57 9 44 318 -7 -21 50 13 -20 47 27 -23 34 24 -19 8 1 144 0 0 -21 2 51 8 57 13 43 317 -8 -21 34 18 -20 31 42 -23 18 11 -18 52 31 145 0 0 -20 47 36 8 57 17 43 316 -8 -21 18 57 -20 16 31 -23 2 33 -18 37 35 146 0 0 -20 32 55 8 57 21 42 315 -9 -21 4 11 -20 1 55 -22 47 30 -18 23 14 147 0 0 -20 18 49 8 57 24 42 313 -10 -20 50 0 -19 47 53 -22 33 3 -18 9 27 148 0 0 -20 5 18 8 57 28 41 312 -11 -20 36 25 -19 34 27 -22 19 12 -17 56 14 149 0 0 -19 52 22 8 57 32 41 311 -12 -20 23 25 -19 21 35 -22 5 57 -17 43 35 150 0 0 -19 40 2 8 57 35 40 310 -13 -20 11 1 -19 9 19 -21 53 19 -17 31 32 151 0 0 -19 28 18 8 57 39 39 309 -14 -19 59 12 -18 57 39 -21 41 17 -17 20 3 152 0 0 -19 17 9 8 57 43 39 308 -15 -19 48 0 -18 46 34 -21 29 51 -17 9 10 153 0 0 -19 6 36 8 57 46 38 308 -16 -19 37 23 -18 36 5 -21 19 2 -16 58 51 154 0 0 -18 56 39 8 57 49 38 307 -17 -19 27 23 -18 26 11 -21 8 50 -16 49 8 155 0 0 -18 47 19 8 57 53 37 306 -18 -19 17 59 -18 16 53 -20 59 15 -16 40 0 156 0 0 -18 38 34 8 57 56 36 305 -19 -19 9 11 -18 8 12 -20 50 17 -16 31 27 157 0 0 -18 30 25 8 57 59 35 304 -20 -19 1 0 -18 0 6 -20 41 56 -16 23 30 158 0 0 -18 22 53 8 58 2 35 303 -21 -18 53 25 -17 52 36 -20 34 13 -16 16 8 159 0 0 -18 15 57 8 58 6 34 303 -22 -18 46 27 -17 45 43 -20 27 6 -16 9 22 160 0 0 -18 9 38 8 58 9 33 302 -23 -18 40 5 -17 39 26 -20 20 37 -16 3 12 161 0 0 -18 3 55 8 58 12 32 301 -24 -18 34 20 -17 33 45 -20 14 45 -15 57 37 162 0 0 -17 58 48 8 58 15 32 301 -25 -18 29 12 -17 28 40 -20 9 30 -15 52 38 163 0 0 -17 54 18 8 58 17 31 300 -26 -18 24 40 -17 24 11 -20 4 52 -15 48 14 164 0 0 -17 50 25 8 58 20 30 299 -27 -18 20 45 -17 20 19 -20 0 52 -15 44 26 165 0 0 -17 47 8 8 58 23 29 299 -28 -18 17 27 -17 17 3 -19 57 30 -15 41 14 166 0 0 -17 44 27 8 58 26 28 298 -29 -18 14 45 -17 14 24 -19 54 45 -15 38 38 167 0 0 -17 42 23 8 58 28 28 298 -30 -18 12 40 -17 12 20 -19 52 37 -15 36 37 168 0 0 -17 40 55 8 58 31 27 297 -31 -18 11 12 -17 10 53 -19 51 6 -15 35 12 169 0 0 -17 40 4 8 58 33 26 297 -32 -18 10 20 -17 10 3 -19 50 13 -15 34 22 170 0 0 -17 39 49 8 58 35 25 296 -33 -18 10 5 -17 9 48 -19 49 57 -15 34 9 171 0 0 -17 40 11 8 58 38 24 296 -33 -18 10 27 -17 10 10 -19 50 18 -15 34 30 172 0 0 -17 41 9 8 58 40 23 295 -34 -18 11 25 -17 11 8 -19 51 17 -15 35 28 173 0 0 -17 42 43 8 58 42 22 295 -35 -18 12 59 -17 12 42 -19 52 52 -15 37 1 174 0 0 -17 44 54 8 58 44 22 294 -36 -18 15 10 -17 14 52 -19 55 5 -15 39 9 175 0 0 -17 47 40 8 58 46 21 294 -37 -18 17 58 -17 17 38 -19 57 55 -15 41 53 176 0 0 -17 51 3 8 58 48 20 293 -38 -18 21 22 -17 21 0 -20 1 22 -15 45 12 177 0 0 -17 55 2 8 58 50 19 293 -39 -18 25 22 -17 24 57 -20 5 26 -15 49 7 178 0 0 -17 59 37 8 58 51 18 292 -40 -18 29 58 -17 29 31 -20 10 7 -15 53 36 179 0 0 -18 4 48 8 58 53 17 292 -41 -18 35 10 -17 34 41 -20 15 25 -15 58 41 180 0 0 -18 10 35 8 58 55 16 292 -42 -18 40 59 -17 40 26 -20 21 19 -16 4 21 -179 0 0 -18 16 57 8 58 56 15 291 -43 -18 47 23 -17 46 46 -20 27 50 -16 10 36 -178 0 0 -18 23 55 8 58 58 14 291 -44 -18 54 23 -17 53 42 -20 34 57 -16 17 26 -177 0 0 -18 31 29 8 58 59 13 291 -45 -19 1 59 -18 1 14 -20 42 41 -16 24 51 -176 0 0 -18 39 38 8 59 0 12 290 -45 -19 10 11 -18 9 20 -20 51 0 -16 32 50 -175 0 0 -18 48 22 8 59 1 11 290 -46 -19 18 58 -18 18 2 -20 59 56 -16 41 23 -174 0 0 -18 57 42 8 59 2 10 289 -47 -19 28 20 -18 27 19 -21 9 28 -16 50 32 -173 0 0 -19 7 36 8 59 3 9 289 -48 -19 38 17 -18 37 10 -21 19 36 -17 0 14 -172 0 0 -19 18 5 8 59 4 9 289 -49 -19 48 50 -18 47 36 -21 30 20 -17 10 31 -171 0 0 -19 29 9 8 59 5 8 288 -50 -19 59 57 -18 58 37 -21 41 39 .. .. .. -170 0 0 -19 40 48 8 59 5 7 288 -51 -20 11 39 -19 10 12 -21 53 33 .. .. .. -169 0 0 -19 53 1 8 59 6 6 288 -51 -20 23 56 -19 22 21 -22 6 3 .. .. .. -168 0 0 -20 5 48 8 59 7 5 287 -52 -20 36 47 -19 35 4 -22 19 7 .. .. .. -167 0 0 -20 19 9 8 59 7 4 287 -53 -20 50 12 -19 48 21 -22 32 46 .. .. .. -166 0 0 -20 33 3 8 59 7 3 287 -54 -21 4 11 -20 2 12 -22 47 0 .. .. .. -165 0 0 -20 47 31 8 59 7 2 286 -54 -21 18 43 -20 16 35 -23 1 47 .. .. .. -164 0 0 -21 2 33 8 59 8 1 286 -55 -21 33 49 -20 31 32 -23 17 9 .. .. .. Uncertainty in time = +/- 5 secs [Prediction of 2008 Feb 14.0] Data for the target star ------------------------ * name: UCAC2 36945116 * constellation : Orion * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 04 49 46.9902 DE: +14 32 16.041 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .047, .050 ) * V mag [mag]: 11.7 * B mag [mag]: 0.0 * Apparent position with proper motion RA(deg): 72.5628514950 DE(deg): 14.5530271230 * Equation of equinoxes (radians) : 0.000040694340741 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (850) Altona approx. diameter [km]: 81 approx. diameter ["]: .031 distance from Earth [AU]: 3.64100 * orbital information: orbit source: Preston date of fit: 2008 Feb 13 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 697 number of rejected observations: 59 time covered by the observations: 1917 Jul 28 - 2008 Jan 27 1 sigma uncertainty ellipse (major, minor, PA): 0.015, 0.010, 70° remarks: * orbital elements for (850) Altona : Mean anomaly = 199.60414213 deg Arg. of pericenter = 130.95077718 deg Long. of node = 121.47073804 deg Inclination = 15.48487156 deg Eccentricity = 0.12701164 Semimajor axis = 3.00037200 AU Perihelion dist = 2.61928982 AU Mag: H = 9.63, G = 0.15 Epoch of elements : MJD 54552.37200000 TDT (2008 Mar 27.372) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Mar 27 850 Altona 8h 56.2m UT 11.7 4 49 46.990 14 32 16.04UCAC2 36945116 0.0 15.9 81 3.0 3.641 2.344 13.24 113.2237 14.534 47.27 2.81 8.9372 0.24778 -0.63697 14.09003 5.48461 0.00538 0.00033 2000 199.1543042008 325.00000130.950777121.470738 15.4848720.12701164 3.0003720 2.6192898 9.6 5.00.15 RATE 1.8964500 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.050 0.049 359 2.62 0.050 0 54510.5020080327_945116 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Feb 14, 19:55 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org