IOTA/IOTA-ES occultation update for (1) Ceres / TYC 1926-00270-1 event on 2008 Aug 16, 11:24 UT Visible from S Mexico Summary ------- On 2008 Aug 16 UT, the 960 km diameter asteroid (1) Ceres will occult a 8.7 mag star in the constellation Cancer for observers along a path across S Mexico. In the case of an occultation, the combined light of the asteroid and the star will drop by 0.8 mag to 8.8 mag (the magnitude of the asteroid) for at most 21.2 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: 100 * date and approx. time of event: 2008 Aug 16, 11:22 - 2008 Aug 16, 11:22 UT * magnitude of target star: 8.7 * magnitude drop [mag]: 0.8 * estimated maximum duration [s]: 21.2 * Moon: 100 % sunlit, 159° distance * Sun: 26° distance * rough path description: S Mexico Additional comments ------------------- low altitude The occultation path -------------------- * approximate projected width [km]: 961 * 1 sigma uncertainty interval [path widths]: +/- 0.06 * 1 sigma uncertainty interval [seconds]: +/- 1.0 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .020 +/- .023) * 1 sigma uncertainty ellipse (major, minor, PA): ( .023", .020", 0° ) * approx speed of asteroid's shadow [km/s]: 45.2475 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 1926-00270-1 by 1 Ceres on 2008 Aug 16 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 9 31 47 11 22 29 1 66 -25 .. .. .. 14 19 16 .. .. .. 14 53 57 -107 0 0 9 58 47 11 22 29 2 66 -24 .. .. .. 14 46 0 .. .. .. 15 20 39 -106 0 0 10 25 35 11 22 29 3 66 -23 5 40 0 15 12 32 5 5 43 15 47 9 -105 0 0 10 52 13 11 22 30 4 66 -21 6 6 54 15 38 51 5 32 40 16 13 26 -104 0 0 11 18 38 11 22 30 5 66 -20 6 33 38 16 4 58 5 59 26 16 39 31 -103 0 0 11 44 51 11 22 30 6 67 -19 7 0 9 16 30 51 6 26 0 17 5 21 -102 0 0 12 10 50 11 22 30 7 67 -18 7 26 29 16 56 30 6 52 21 17 30 58 -101 0 0 12 36 36 11 22 31 8 67 -17 7 52 35 17 21 54 7 18 30 17 56 20 -100 0 0 13 2 7 11 22 31 9 67 -16 8 18 28 17 47 4 7 44 25 18 21 26 - 99 0 0 13 27 23 11 22 31 10 67 -15 8 44 6 18 11 57 8 10 6 18 46 16 - 98 0 0 13 52 24 11 22 32 11 68 -14 9 9 30 18 36 34 8 35 33 19 10 51 - 97 0 0 14 17 9 11 22 32 12 68 -13 9 34 39 19 0 55 9 0 45 19 35 8 - 96 0 0 14 41 37 11 22 33 13 68 -12 9 59 32 19 24 58 9 25 40 19 59 9 - 95 0 0 15 5 49 11 22 34 14 68 -11 10 24 8 19 48 44 9 50 20 20 22 51 - 94 0 0 15 29 43 11 22 34 15 69 -10 10 48 28 20 12 12 10 14 43 20 46 16 - 93 0 0 15 53 19 11 22 35 17 69 -9 11 12 30 20 35 22 10 38 48 21 9 23 - 92 0 0 16 16 37 11 22 36 18 69 -8 11 36 15 20 58 12 11 2 36 21 32 10 - 91 0 0 16 39 37 11 22 37 19 69 -7 11 59 42 21 20 44 11 26 6 21 54 39 - 90 0 0 17 2 17 11 22 37 20 70 -6 12 22 50 21 42 57 11 49 17 22 16 48 - 89 0 0 17 24 38 11 22 38 21 70 -5 12 45 39 22 4 49 12 12 10 22 38 37 - 88 0 0 17 46 40 11 22 39 22 70 -4 13 8 8 22 26 22 12 34 43 23 0 6 - 87 0 0 18 8 21 11 22 40 23 71 -3 13 30 18 22 47 34 12 56 56 23 21 14 - 86 0 0 18 29 42 11 22 41 24 71 -2 13 52 8 23 8 26 13 18 49 23 42 2 - 85 0 0 18 50 42 11 22 42 25 71 -1 14 13 37 23 28 56 13 40 22 24 2 30 Uncertainty in time = +/- 1 secs [Prediction of 2008 Aug 12.0] Data for the target star ------------------------ * name: TYC 1926-00270-1 * constellation : Cancer * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 08 05 27.5755 DE: +24 11 25.810 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .018, .023 ) * V mag [mag]: 8.7 * B mag [mag]: 9.6 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (1) Ceres approx. diameter [km]: 960 approx. diameter ["]: .381 distance from Earth [AU]: 3.47600 * orbital information: orbit source: Preston date of fit: 2008 Aug 11 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 5437 number of rejected observations: 642 time covered by the observations: 1900 Jul 15 - 2008 Apr 14 1 sigma uncertainty ellipse (major, minor, PA): 0.008, 0.005, 94° remarks: * orbital elements for (1) Ceres : Mean anomaly = 321.91331565 deg Arg. of pericenter = 72.93428404 deg Long. of node = 80.40648262 deg Inclination = 10.58611619 deg Eccentricity = 0.07951443 Semimajor axis = 2.76682185 AU Perihelion dist = 2.54681960 AU Mag: H = 3.37, G = 0.12 Epoch of elements : MJD 54694.47600000 TDT (2008 Aug 16.476) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Aug 16 1 Ceres 11h 24.8m UT 8.7 8 5 27.576 24 11 25.81TYC 1926-00270-1 9.6 8.8 960 21.2 3.476 4.684 -8.20 -15.0720 24.193 9.84 13.53 11.4139 0.00683 0.04888 25.33239 -3.24179 -0.00224 0.00081 2000 320.9547492008 812.00000 72.934284 80.406483 10.5861160.07951443 2.7668219 2.5468196 3.3 5.00.12 RATE 2.1415700 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.023 0.020 0 1.06 0.023 0 54690.5020080816_0270-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Aug 12, 02:12 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org