IOTA/IOTA-ES occultation update for (17) Thetis / TYC 6286-02068-1 event on 2008 Mar 26, 10:30 UT Visible from Peru Summary ------- On 2008 Mar 26 UT, the 90 km diameter asteroid (17) Thetis will occult a 11.7 mag star in the constellation Sagittarius for observers along a path across Peru. In the case of an occultation, the combined light of the asteroid and the star will drop by 1.0 mag to 12.2 mag (the magnitude of the asteroid) for at most 3.8 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: 57 * date and approx. time of event: 2008 Mar 26, 10:25 - 2008 Mar 26, 10:29 UT * midpoint of event [JD]: 2454551.93744583 * magnitude of target star: 11.7 * magnitude drop [mag]: 1.0 * estimated maximum duration [s]: 3.8 * Moon: 81 % sunlit, 47° distance * Sun: 82° distance * rough path description: Peru The occultation path -------------------- * approximate projected width [km]: 92 * 1 sigma uncertainty interval [path widths]: +/- 1.10 * 1 sigma uncertainty interval [seconds]: +/- 3.8 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .065 +/- .067) * 1 sigma uncertainty ellipse (major, minor, PA): ( .067", .065", 0° ) * approx speed of asteroid's shadow [km/s]: 23.9346 * website for maps: http://lunar-occultations.com/iota/asteroids/astrndx.htm http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 6286-02068-1 by 17 Thetis on 2008 Mar 26 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 -144 0 0 4 50 40 10 25 34 0 108 -77 4 24 29 .. .. .. 3 27 2 .. .. .. -143 0 0 4 30 48 10 25 34 1 108 -76 4 4 38 4 57 0 3 7 13 5 54 47 -142 0 0 4 11 4 10 25 34 2 108 -75 3 44 55 4 37 14 2 47 33 5 34 59 -141 0 0 3 51 28 10 25 34 3 109 -75 3 25 21 4 17 38 2 28 1 5 15 20 -140 0 0 3 32 2 10 25 34 4 109 -74 3 5 56 3 58 10 2 8 38 4 55 50 -139 0 0 3 12 45 10 25 35 5 109 -73 2 46 40 3 38 52 1 49 26 4 36 29 -138 0 0 2 53 38 10 25 35 6 109 -72 2 27 34 3 19 44 1 30 23 4 17 18 -137 0 0 2 34 41 10 25 36 7 109 -71 2 8 39 3 0 46 1 11 30 3 58 17 -136 0 0 2 15 55 10 25 37 8 109 -70 1 49 54 2 41 58 0 52 48 3 39 26 -135 0 0 1 57 20 10 25 37 10 109 -70 1 31 20 2 23 22 0 34 17 3 20 47 -134 0 0 1 38 56 10 25 38 11 109 -69 1 12 58 2 4 57 0 15 58 3 2 19 -133 0 0 1 20 45 10 25 39 12 109 -68 0 54 48 1 46 44 - 0 2 9 2 44 2 -132 0 0 1 2 45 10 25 40 13 109 -67 0 36 50 1 28 43 - 0 20 3 2 25 58 -131 0 0 0 44 59 10 25 41 14 109 -66 0 19 5 1 10 55 - 0 37 45 2 8 7 -130 0 0 0 27 25 10 25 43 15 109 -65 0 1 33 0 53 19 - 0 55 14 1 50 28 -129 0 0 0 10 5 10 25 44 16 109 -64 - 0 15 46 0 35 58 - 1 12 30 1 33 3 -128 0 0 - 0 7 2 10 25 45 17 109 -63 - 0 32 51 0 18 49 - 1 29 32 1 15 51 -127 0 0 - 0 23 55 10 25 47 18 109 -62 - 0 49 42 0 1 55 - 1 46 19 0 58 54 -126 0 0 - 0 40 33 10 25 48 19 109 -61 - 1 6 19 - 0 14 45 - 2 2 53 0 42 10 -125 0 0 - 0 56 57 10 25 50 20 109 -60 - 1 22 41 - 0 31 10 - 2 19 11 0 25 42 -124 0 0 - 1 13 5 10 25 52 21 109 -59 - 1 38 48 - 0 47 20 - 2 35 15 0 9 28 -123 0 0 - 1 28 58 10 25 54 22 109 -58 - 1 54 40 - 1 3 15 - 2 51 3 - 0 6 30 -122 0 0 - 1 44 36 10 25 55 23 109 -57 - 2 10 15 - 1 18 54 - 3 6 35 - 0 22 13 -121 0 0 - 1 59 57 10 25 57 24 109 -56 - 2 25 36 - 1 34 17 - 3 21 52 - 0 37 40 -120 0 0 - 2 15 3 10 25 59 25 109 -55 - 2 40 39 - 1 49 24 - 3 36 52 - 0 52 50 -119 0 0 - 2 29 52 10 26 2 26 109 -54 - 2 55 27 - 2 4 15 - 3 51 36 - 1 7 44 -118 0 0 - 2 44 24 10 26 4 27 109 -53 - 3 9 57 - 2 18 48 - 4 6 3 - 1 22 22 -117 0 0 - 2 58 39 10 26 6 28 109 -52 - 3 24 11 - 2 33 5 - 4 20 13 - 1 36 42 -116 0 0 - 3 12 37 10 26 8 29 109 -51 - 3 38 7 - 2 47 5 - 4 34 6 - 1 50 45 -115 0 0 - 3 26 18 10 26 11 30 109 -50 - 3 51 46 - 3 0 47 - 4 47 41 - 2 4 30 -114 0 0 - 3 39 40 10 26 13 31 109 -49 - 4 5 7 - 3 14 11 - 5 0 59 - 2 17 58 -113 0 0 - 3 52 45 10 26 16 32 109 -48 - 4 18 10 - 3 27 17 - 5 13 59 - 2 31 8 -112 0 0 - 4 5 31 10 26 19 33 109 -47 - 4 30 55 - 3 40 5 - 5 26 41 - 2 43 59 -111 0 0 - 4 18 0 10 26 21 34 109 -46 - 4 43 22 - 3 52 35 - 5 39 4 - 2 56 32 -110 0 0 - 4 30 9 10 26 24 35 109 -45 - 4 55 30 - 4 4 46 - 5 51 9 - 3 8 47 -109 0 0 - 4 42 0 10 26 27 36 109 -44 - 5 7 20 - 4 16 38 - 6 2 55 - 3 20 42 -108 0 0 - 4 53 32 10 26 30 37 109 -43 - 5 18 50 - 4 28 12 - 6 14 22 - 3 32 19 -107 0 0 - 5 4 45 10 26 33 38 109 -42 - 5 30 1 - 4 39 26 - 6 25 30 - 3 43 36 -106 0 0 - 5 15 38 10 26 36 39 109 -41 - 5 40 53 - 4 50 21 - 6 36 19 - 3 54 34 -105 0 0 - 5 26 12 10 26 39 40 109 -40 - 5 51 26 - 5 0 56 - 6 46 49 - 4 5 12 -104 0 0 - 5 36 26 10 26 42 41 110 -39 - 6 1 39 - 5 11 11 - 6 56 59 - 4 15 31 -103 0 0 - 5 46 21 10 26 46 43 110 -38 - 6 11 32 - 5 21 7 - 7 6 49 - 4 25 29 -102 0 0 - 5 55 55 10 26 49 44 110 -37 - 6 21 5 - 5 30 43 - 7 16 19 - 4 35 8 -101 0 0 - 6 5 10 10 26 52 45 110 -36 - 6 30 18 - 5 39 59 - 7 25 30 - 4 44 26 -100 0 0 - 6 14 4 10 26 56 46 110 -35 - 6 39 11 - 5 48 54 - 7 34 20 - 4 53 24 - 99 0 0 - 6 22 38 10 26 59 47 110 -34 - 6 47 44 - 5 57 29 - 7 42 50 - 5 2 2 - 98 0 0 - 6 30 51 10 27 3 47 110 -33 - 6 55 56 - 6 5 44 - 7 51 0 - 5 10 19 - 97 0 0 - 6 38 44 10 27 6 48 110 -32 - 7 3 48 - 6 13 38 - 7 58 50 - 5 18 16 - 96 0 0 - 6 46 16 10 27 10 49 110 -31 - 7 11 19 - 6 21 11 - 8 6 19 - 5 25 51 - 95 0 0 - 6 53 27 10 27 13 50 111 -30 - 7 18 30 - 6 28 23 - 8 13 27 - 5 33 6 - 94 0 0 - 7 0 18 10 27 17 51 111 -29 - 7 25 19 - 6 35 15 - 8 20 14 - 5 39 59 - 93 0 0 - 7 6 48 10 27 21 52 111 -28 - 7 31 48 - 6 41 45 - 8 26 41 - 5 46 32 - 92 0 0 - 7 12 56 10 27 25 53 111 -27 - 7 37 55 - 6 47 55 - 8 32 47 - 5 52 43 - 91 0 0 - 7 18 43 10 27 29 54 111 -26 - 7 43 42 - 6 53 43 - 8 38 31 - 5 58 33 - 90 0 0 - 7 24 10 10 27 33 55 112 -25 - 7 49 7 - 6 59 10 - 8 43 55 - 6 4 2 - 89 0 0 - 7 29 14 10 27 37 56 112 -24 - 7 54 11 - 7 4 15 - 8 48 57 - 6 9 9 - 88 0 0 - 7 33 58 10 27 41 57 112 -23 - 7 58 54 - 7 8 59 - 8 53 39 - 6 13 55 - 87 0 0 - 7 38 20 10 27 45 58 113 -22 - 8 3 16 - 7 13 22 - 8 57 59 - 6 18 19 - 86 0 0 - 7 42 21 10 27 49 59 113 -21 - 8 7 16 - 7 17 23 - 9 1 58 - 6 22 21 - 85 0 0 - 7 46 0 10 27 53 60 114 -20 - 8 10 54 - 7 21 3 - 9 5 35 - 6 26 2 - 84 0 0 - 7 49 17 10 27 57 61 114 -19 - 8 14 11 - 7 24 21 - 9 8 51 - 6 29 21 - 83 0 0 - 7 52 13 10 28 1 62 115 -18 - 8 17 7 - 7 27 17 - 9 11 46 - 6 32 18 - 82 0 0 - 7 54 47 10 28 6 63 115 -17 - 8 19 41 - 7 29 52 - 9 14 19 - 6 34 54 - 81 0 0 - 7 57 0 10 28 10 64 116 -16 - 8 21 53 - 7 32 5 - 9 16 30 - 6 37 7 - 80 0 0 - 7 58 51 10 28 14 65 117 -15 - 8 23 43 - 7 33 56 - 9 18 20 - 6 38 59 - 79 0 0 - 8 0 20 10 28 18 66 117 -14 - 8 25 12 - 7 35 25 - 9 19 48 - 6 40 29 - 78 0 0 - 8 1 27 10 28 23 67 118 -13 - 8 26 19 - 7 36 33 - 9 20 55 - 6 41 37 - 77 0 0 - 8 2 13 10 28 27 67 119 -12 - 8 27 5 - 7 37 18 - 9 21 40 - 6 42 22 - 76 0 0 - 8 2 36 10 28 32 68 120 -11 - 8 27 28 - 7 37 42 - 9 22 4 - 6 42 46 - 75 0 0 - 8 2 38 10 28 36 69 122 -9 - 8 27 30 - 7 37 44 - 9 22 6 - 6 42 48 - 74 0 0 - 8 2 18 10 28 41 70 123 -8 - 8 27 10 - 7 37 24 - 9 21 46 - 6 42 28 - 73 0 0 - 8 1 36 10 28 45 71 124 -7 - 8 26 29 - 7 36 42 - 9 21 5 - 6 41 46 - 72 0 0 - 8 0 33 10 28 50 72 126 -6 - 8 25 25 - 7 35 38 - 9 20 1 - 6 40 42 - 71 0 0 - 7 59 7 10 28 54 73 128 -5 - 8 24 0 - 7 34 12 - 9 18 37 - 6 39 15 - 70 0 0 - 7 57 20 10 28 59 73 130 -4 - 8 22 13 - 7 32 25 - 9 16 50 - 6 37 27 - 69 0 0 - 7 55 11 10 29 3 74 132 -3 - 8 20 4 - 7 30 15 - 9 14 42 - 6 35 17 - 68 0 0 - 7 52 40 10 29 8 75 134 -2 - 8 17 34 - 7 27 44 - 9 12 13 - 6 32 45 - 67 0 0 - 7 49 47 10 29 13 75 137 -1 - 8 14 41 - 7 24 51 - 9 9 21 - 6 29 51 - 66 0 0 - 7 46 33 10 29 17 76 140 0 - 8 11 28 - 7 21 36 - 9 6 9 - 6 26 35 Uncertainty in time = +/- 4 secs [Prediction of 2008 Feb 14.0] Data for the target star ------------------------ * name: TYC 6286-02068-1 * constellation : Sagittarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 18 59 15.7003 DE: -18 16 31.348 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .065, .067 ) * V mag [mag]: 11.7 * B mag [mag]: 12.6 * Apparent position with proper motion RA(deg): 284.9374708638 DE(deg): -18.2660443187 * Equation of equinoxes (radians) : 0.000040613680315 * remarks:no mean pos in Tycho2 Data for the minor planet ------------------------- * general information: (number) name: (17) Thetis approx. diameter [km]: 90 approx. diameter ["]: .061 distance from Earth [AU]: 2.03700 * orbital information: orbit source: Preston date of fit: 2008 Feb 13 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1632 number of rejected observations: 233 time covered by the observations: 1900 Oct 03 - 2007 Jun 26 1 sigma uncertainty ellipse (major, minor, PA): 0.008, 0.005, 91° remarks: * orbital elements for (17) Thetis : Mean anomaly = 356.02828987 deg Arg. of pericenter = 136.02328683 deg Long. of node = 125.60290068 deg Inclination = 5.58779271 deg Eccentricity = 0.13483042 Semimajor axis = 2.47045182 AU Perihelion dist = 2.13735976 AU Mag: H = 7.67, G = 0.15 Epoch of elements : MJD 54551.43800000 TDT (2008 Mar 26.438) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Mar 26 17 Thetis 10h 29.9m UT 11.7 18 59 15.700-18 16 31.35TYC 6286-02068-1 12.6 12.2 90 3.8 2.037 4.072 6.25 -56.9078 -18.277 23.92 2.44 10.4987 -0.01956 0.19407 13.43165 1.44691 -0.00534 -0.00048 2000 355.6632852008 325.00000136.023287125.602901 5.5877930.13483042 2.4704518 2.1373598 7.8 5.00.15 RATE 2.5382800 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.067 0.065 0 2.10 0.067 0 54510.5020080326_2068-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Feb 14, 19:47 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org