IOTA/IOTA-ES occultation update for (196) Philomela / TYC 6869-00695-1 event on 2012 Oct 04, 02:14 UT Visible from Canada, NW USA Summary ------- On 2012 Oct 04 UT, the 142 km diameter asteroid (196) Philomela will occult a 9.7 mag star in the constellation Sagittarius for observers along a path across Canada, NW USA. In the case of an occultation, the combined light of the asteroid and the star will drop by 2.7 mag to 12.3 mag (the magnitude of the asteroid) for at most 7.3 seconds. This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Alice Monet, TMO astrometry for the asteroid kindly provided by Bill Owen, historical astrometry from the MPC files (via AstDys), and the following catalogs for the star position: UCAC. The event at a glimpse ---------------------- * Rank: 87 * date and approx. time of event: 2012 Oct 04, 02:14 - 2012 Oct 04, 02:15 UT * geocentric midpoint of event [JD]: 2456204.5931125 * magnitude of target star: 9.7 * magnitude drop [mag]: 2.7 * estimated maximum duration [s]: 7.3 * Moon: 86 % sunlit, 139° distance * Sun: 85° distance * rough path description: Canada, NW USA The occultation path -------------------- * approximate projected width [km]: 471 * 1 sigma uncertainty interval [path widths]: +/- 0.57 * 1 sigma uncertainty interval [seconds]: +/- 3.4 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .034 +/- .038) * 1 sigma uncertainty ellipse (major, minor, PA): ( .038", .034", 0° ) * approx speed of asteroid's shadow [km/s]: 19.4203 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 6869-00695-1 by 196 Philomela on 2012 Oct 4 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 ' " Longitude Longitude Longitude Longitude -104 31 4 59 0 0 2 15 41 0 203 -15 ... .. .. -109 20 39 ... .. .. -115 56 43 -105 22 35 58 0 0 2 15 41 1 202 -15 -101 7 14 -110 10 49 ... .. .. -116 47 36 -106 19 23 57 0 0 2 15 40 2 201 -15 -102 5 4 -111 7 42 ... .. .. -117 48 16 -107 21 36 56 0 0 2 15 39 4 200 -14 -103 7 18 -112 11 36 ... .. .. -118 59 34 -108 29 30 55 0 0 2 15 38 5 199 -14 -104 14 4 -113 22 56 ... .. .. -120 22 56 -109 43 26 54 0 0 2 15 35 6 198 -14 -105 25 36 -114 42 26 ... .. .. -122 0 45 -111 3 55 53 0 0 2 15 33 7 197 -13 -106 42 14 -116 11 11 ... .. .. -123 57 15 -112 31 45 52 0 0 2 15 29 8 196 -12 -108 4 24 -117 50 48 ... .. .. -126 20 40 -114 7 58 51 0 0 2 15 25 10 194 -11 -109 32 43 -119 43 48 ... .. .. -129 31 23 -115 54 9 50 0 0 2 15 20 11 193 -10 -111 8 1 -121 54 23 -106 29 40 -135 19 15 -117 52 36 49 0 0 2 15 13 12 191 -9 -112 51 25 -124 30 22 -108 4 16 ... .. .. -120 7 6 48 0 0 2 15 6 13 189 -8 -114 44 32 -127 49 44 -109 45 32 ... .. .. Latitude Latitude Latitude Latitude -122 0 0 47 15 50 2 14 59 14 187 -6 44 58 11 49 57 38 42 40 0 54 0 26 -123 0 0 46 54 32 2 14 55 15 187 -6 44 38 46 49 33 17 42 22 4 53 28 5 -124 0 0 46 34 44 2 14 51 15 186 -5 44 20 40 49 10 45 42 5 19 52 58 43 -125 0 0 46 16 21 2 14 47 15 185 -4 44 3 51 48 49 56 41 49 43 52 32 1 -126 0 0 45 59 24 2 14 44 16 184 -4 43 48 17 48 30 48 41 35 16 52 7 48 -127 0 0 45 43 50 2 14 40 16 183 -3 43 33 59 48 13 18 41 21 59 51 45 53 -128 0 0 45 29 38 2 14 35 16 182 -2 43 20 55 47 57 23 41 9 49 51 26 8 -129 0 0 45 16 47 2 14 31 17 181 -1 43 9 4 47 43 1 40 58 48 51 8 27 -130 0 0 45 5 17 2 14 27 17 180 -1 42 58 27 47 30 11 40 48 54 50 52 45 Uncertainty in time = +/- 4 secs Prediction of 2012 Sep 27.0 Data for the target star ------------------------ * name: TYC 6869-00695-1 * constellation : Sagittarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 18 26 11.7760 DE: -28 20 11.767 * position source: mpos:UCAC4 pm:UCAC4 * standard error: RA,DE ["]: ( .034, .037 ) * V mag [mag]: 9.7 * B mag [mag]: 11.2 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (196) Philomela approx. diameter [km]: 142 approx. diameter ["]: .066 distance from Earth [AU]: 2.98100 * orbital information: orbit source: Preston date of fit: 2012 Sep 07 source of used astrometry: FASTT TMO MPC (via Astdys) number of used observations: 1679 number of rejected observations: 193 time covered by the observations: 1904 Nov 16 - 2012 Sep 01 1 sigma uncertainty ellipse (major, minor, PA): 0.008, 0.006, 96° remarks: * orbital elements for (196) Philomela : Mean anomaly = 22.06300268 deg Arg. of pericenter = 199.63162603 deg Long. of node = 72.53083111 deg Inclination = 7.26009410 deg Eccentricity = 0.02005840 Semimajor axis = 3.11371217 AU Perihelion dist = 3.05125608 AU Mag: H = 6.44, G = 0.15 Epoch of elements : MJD 56204.09300000 TDT (2012 Oct 04.093) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Oct 4 196 Philomela 2h 14.1m UT 9.7 18 26 11.776-28 20 11.77TYC 6869-00695-1 11.2 12.3 142 7.3 2.981 2.444 2.30 -130.1520 -28.336 143.66 -4.46 2.2347 -0.06743 0.95099 10.93359 0.77945 0.00576 0.00022 2000 21.3287802012 930.00000199.631626 72.530831 7.2600940.02005840 3.1137122 3.0512561 6.5 5.00.15 RATE 1.7938510 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.038 0.034 0 1.57 0.038 0 0 0 3 056197.0020121004_0695-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Sep 07, 22:21 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org