IOTA/IOTA-ES occultation update for (540) Rosamunde / TYC 0251-00825-1 event on 2008 Oct 18, 01:39 UT Visible from S Africa Summary ------- On 2008 Oct 18 UT, the 19 km diameter asteroid (540) Rosamunde will occult a 9.9 mag star in the constellation Leo for observers along a path across S Africa. In the case of an occultation, the combined light of the asteroid and the star will drop by 5.5 mag to 15.4 mag (the magnitude of the asteroid) for at most 0.5 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: 28 * date and approx. time of event: 2008 Oct 18, 01:37 - 2008 Oct 18, 01:38 UT * midpoint of event [JD]: 2454757.56893333 * magnitude of target star: 9.9 * magnitude drop [mag]: 5.5 * estimated maximum duration [s]: 0.5 * Moon: 86 % sunlit, 84° distance * Sun: 53° distance * rough path description: S Africa The occultation path -------------------- * approximate projected width [km]: 31 * 1 sigma uncertainty interval [path widths]: +/- 2.43 * 1 sigma uncertainty interval [seconds]: +/- 1.3 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .027 +/- .024) * 1 sigma uncertainty ellipse (major, minor, PA): ( .027", .024", 95° ) * approx speed of asteroid's shadow [km/s]: 37.9686 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 0251-00825-1 by 540 Rosamunde on 2008 Oct 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 ' " Longitude Longitude Longitude Longitude Latitude Latitude Latitude Latitude 55 0 0 -34 4 37 1 38 20 30 57 0 -34 13 35 -33 55 40 -34 57 40 -33 12 40 54 0 0 -33 49 18 1 38 18 30 58 -1 -33 58 15 -33 40 23 -34 42 11 -32 57 31 53 0 0 -33 34 32 1 38 16 29 58 -2 -33 43 27 -33 25 39 -34 27 14 -32 42 54 52 0 0 -33 20 17 1 38 14 29 59 -3 -33 29 11 -33 11 26 -34 12 50 -32 28 49 51 0 0 -33 6 36 1 38 12 28 60 -4 -33 15 27 -32 57 46 -33 58 59 -32 15 16 50 0 0 -32 53 27 1 38 10 27 61 -4 -33 2 17 -32 44 38 -33 45 41 -32 2 15 49 0 0 -32 40 51 1 38 8 27 62 -5 -32 49 40 -32 32 4 -33 32 57 -31 49 48 48 0 0 -32 28 48 1 38 6 26 63 -6 -32 37 35 -32 20 2 -33 20 46 -31 37 53 47 0 0 -32 17 19 1 38 4 25 64 -7 -32 26 5 -32 8 34 -33 9 9 -31 26 31 46 0 0 -32 6 23 1 38 2 25 64 -8 -32 15 8 -31 57 40 -32 58 5 -31 15 42 45 0 0 -31 56 1 1 38 1 24 65 -9 -32 4 45 -31 47 19 -32 47 36 -31 5 27 44 0 0 -31 46 13 1 37 59 23 66 -10 -31 54 55 -31 37 32 -32 37 41 -30 55 45 43 0 0 -31 36 59 1 37 57 23 67 -11 -31 45 40 -31 28 19 -32 28 21 -30 46 37 42 0 0 -31 28 19 1 37 56 22 67 -11 -31 36 59 -31 19 40 -32 19 35 -30 38 3 41 0 0 -31 20 13 1 37 54 21 68 -12 -31 28 53 -31 11 35 -32 11 24 -30 30 2 40 0 0 -31 12 42 1 37 53 20 69 -13 -31 21 21 -31 4 5 -32 3 48 -30 22 36 39 0 0 -31 5 46 1 37 51 20 69 -14 -31 14 24 -30 57 9 -31 56 46 -30 15 44 38 0 0 -30 59 23 1 37 50 19 70 -15 -31 8 1 -30 50 48 -31 50 20 -30 9 26 37 0 0 -30 53 36 1 37 48 18 71 -16 -31 2 13 -30 45 1 -31 44 28 -30 3 43 36 0 0 -30 48 23 1 37 47 17 71 -16 -30 56 59 -30 39 49 -31 39 12 -29 58 34 35 0 0 -30 43 45 1 37 46 16 72 -17 -30 52 21 -30 35 12 -31 34 30 -29 53 59 34 0 0 -30 39 42 1 37 45 16 73 -18 -30 48 17 -30 31 9 -31 30 24 -29 49 58 33 0 0 -30 36 14 1 37 44 15 73 -19 -30 44 49 -30 27 41 -31 26 54 -29 46 33 32 0 0 -30 33 21 1 37 43 14 74 -20 -30 41 55 -30 24 48 -31 23 58 -29 43 41 31 0 0 -30 31 2 1 37 42 13 74 -21 -30 39 36 -30 22 30 -31 21 38 -29 41 24 30 0 0 -30 29 19 1 37 41 12 75 -21 -30 37 52 -30 20 47 -31 19 53 -29 39 42 29 0 0 -30 28 10 1 37 40 11 75 -22 -30 36 43 -30 19 38 -31 18 43 -29 38 34 28 0 0 -30 27 36 1 37 39 11 76 -23 -30 36 9 -30 19 4 -31 18 8 -29 38 1 27 0 0 -30 27 37 1 37 38 10 77 -24 -30 36 10 -30 19 5 -31 18 9 -29 38 2 26 0 0 -30 28 13 1 37 38 9 77 -24 -30 36 46 -30 19 41 -31 18 45 -29 38 38 25 0 0 -30 29 24 1 37 37 8 78 -25 -30 37 57 -30 20 52 -31 19 56 -29 39 48 24 0 0 -30 31 9 1 37 36 7 78 -26 -30 39 43 -30 22 37 -31 21 43 -29 41 33 23 0 0 -30 33 29 1 37 36 6 79 -27 -30 42 3 -30 24 57 -31 24 4 -29 43 52 22 0 0 -30 36 24 1 37 36 6 79 -27 -30 44 58 -30 27 52 -31 27 1 -29 46 45 21 0 0 -30 39 53 1 37 35 5 80 -28 -30 48 28 -30 31 21 -31 30 32 .. .. .. 20 0 0 -30 43 57 1 37 35 4 80 -29 -30 52 32 -30 35 24 -31 34 38 .. .. .. 19 0 0 -30 48 35 1 37 35 3 81 -29 -30 57 11 -30 40 2 -31 39 19 .. .. .. 18 0 0 -30 53 48 1 37 34 2 81 -30 -31 2 24 -30 45 14 -31 44 35 .. .. .. 17 0 0 -30 59 35 1 37 34 1 82 -31 -31 8 11 -30 51 0 -31 50 25 .. .. .. 16 0 0 -31 5 56 1 37 34 0 82 -31 -31 14 33 -30 57 21 -31 56 50 .. .. .. Uncertainty in time = +/- 1 secs [Prediction of 2008 Sep 12.0] Data for the target star ------------------------ * name: TYC 0251-00825-1 * constellation : Leo * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 10 11 29.1392 DE: +06 30 56.689 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .023, .023 ) * V mag [mag]: 9.9 * B mag [mag]: 11.3 * Apparent position with proper motion RA(deg): 152.9865288082 DE(deg): 6.4734855056 * Equation of equinoxes (radians) : 0.000047380607251 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (540) Rosamunde approx. diameter [km]: 19 approx. diameter ["]: .010 distance from Earth [AU]: 2.52800 * orbital information: orbit source: Preston date of fit: 2008 Sep 05 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 938 number of rejected observations: 112 time covered by the observations: 1904 Aug 03 - 2008 Feb 08 1 sigma uncertainty ellipse (major, minor, PA): 0.014, 0.007, 107° remarks: * orbital elements for (540) Rosamunde : Mean anomaly = 318.28916795 deg Arg. of pericenter = 336.87471919 deg Long. of node = 202.25305075 deg Inclination = 5.57539790 deg Eccentricity = 0.08976826 Semimajor axis = 2.21906662 AU Perihelion dist = 2.01986487 AU Mag: H = 10.54, G = 0.15 Epoch of elements : MJD 54757.06900000 TDT (2008 Oct 18.069) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Oct 18 540 Rosamunde 1h 39.3m UT 9.9 10 11 29.139 6 30 56.69TYC 0251-00825-1 11.3 15.4 19 0.5 2.528 4.650 -27.47 101.1313 6.523 151.47 -9.70 1.6544 -0.29245 -0.74036 19.92255 -7.89687 -0.00406 0.00127 2000 316.18147920081011.00000336.874719202.253051 5.5753980.08976826 2.2190666 2.019864910.8 5.00.15 RATE 2.9815940 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.027 0.024 95 3.43 0.024 0 54721.5020081018_0825-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Sep 12, 18:16 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org