IOTA/IOTA-ES occultation update for (176) Iduna / TYC 0704-01655-1 event on 2008 Aug 21, 23:33 UT Visible from India Summary ------- On 2008 Aug 21 UT, the 121 km diameter asteroid (176) Iduna will occult a 11.4 mag star in the constellation Orion for observers along a path across India. In the case of an occultation, the combined light of the asteroid and the star will drop by 2.2 mag to 13.4 mag (the magnitude of the asteroid) for at most 4.1 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: 96 * date and approx. time of event: 2008 Aug 21, 23:30 - 2008 Aug 21, 23:32 UT * magnitude of target star: 11.4 * magnitude drop [mag]: 2.2 * estimated maximum duration [s]: 4.1 * Moon: 72 % sunlit, 50° distance * Sun: 69° distance * rough path description: India The occultation path -------------------- * approximate projected width [km]: 121 * 1 sigma uncertainty interval [path widths]: +/- 0.40 * 1 sigma uncertainty interval [seconds]: +/- 2.0 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .029 +/- .023) * 1 sigma uncertainty ellipse (major, minor, PA): ( .029", .023", 92° ) * approx speed of asteroid's shadow [km/s]: 29.4696 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 0704-01655-1 by 176 Iduna on 2008 Aug 21 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 25 0 0 17 3 19 23 30 0 0 80 -57 16 30 1 17 36 36 16 3 23 18 3 14 26 0 0 17 13 8 23 30 1 1 80 -56 16 39 52 17 46 23 16 13 15 18 12 59 27 0 0 17 22 38 23 30 1 2 81 -56 16 49 24 17 55 51 16 22 48 18 22 26 28 0 0 17 31 48 23 30 1 3 81 -55 16 58 36 18 5 0 16 32 2 18 31 34 29 0 0 17 40 40 23 30 1 4 81 -54 17 7 29 18 13 50 16 40 57 18 40 22 30 0 0 17 49 12 23 30 1 5 82 -54 17 16 3 18 22 21 16 49 32 18 48 52 31 0 0 17 57 25 23 30 2 6 82 -53 17 24 18 18 30 32 16 57 48 18 57 2 32 0 0 18 5 18 23 30 2 7 82 -52 17 32 12 18 38 24 17 5 44 19 4 52 33 0 0 18 12 52 23 30 3 8 83 -51 17 39 48 18 45 56 17 13 20 19 12 23 34 0 0 18 20 6 23 30 3 9 83 -51 17 47 3 18 53 9 17 20 37 19 19 35 35 0 0 18 27 0 23 30 4 10 83 -50 17 53 59 19 0 2 17 27 33 19 26 27 36 0 0 18 33 35 23 30 4 11 84 -49 18 0 35 19 6 35 17 34 10 19 32 59 37 0 0 18 39 50 23 30 5 12 84 -48 18 6 51 19 12 48 17 40 27 19 39 11 38 0 0 18 45 44 23 30 6 13 84 -48 18 12 47 19 18 42 17 46 24 19 45 4 39 0 0 18 51 19 23 30 7 14 85 -47 18 18 23 19 24 16 17 52 1 19 50 37 40 0 0 18 56 34 23 30 8 15 85 -46 18 23 38 19 29 29 17 57 18 19 55 50 41 0 0 19 1 29 23 30 9 16 85 -45 18 28 34 19 34 23 18 2 14 20 0 43 42 0 0 19 6 3 23 30 10 17 85 -45 18 33 10 19 38 57 18 6 51 20 5 16 43 0 0 19 10 18 23 30 11 18 86 -44 18 37 25 19 43 11 18 11 7 20 9 29 44 0 0 19 14 12 23 30 12 19 86 -43 18 41 20 19 47 4 18 15 2 20 13 21 45 0 0 19 17 46 23 30 13 20 86 -42 18 44 55 19 50 37 18 18 38 20 16 54 46 0 0 19 21 0 23 30 14 21 87 -42 18 48 10 19 53 51 18 21 53 20 20 7 47 0 0 19 23 54 23 30 16 22 87 -41 18 51 4 19 56 43 18 24 47 20 22 59 48 0 0 19 26 27 23 30 17 22 87 -40 18 53 37 19 59 16 18 27 22 20 25 31 49 0 0 19 28 40 23 30 18 23 88 -39 18 55 51 20 1 28 18 29 35 20 27 43 50 0 0 19 30 32 23 30 20 24 88 -38 18 57 43 20 3 20 18 31 28 20 29 35 51 0 0 19 32 4 23 30 21 25 88 -38 18 59 16 20 4 52 18 33 1 20 31 7 52 0 0 19 33 16 23 30 23 26 89 -37 19 0 28 20 6 3 18 34 13 20 32 18 53 0 0 19 34 7 23 30 24 27 89 -36 19 1 19 20 6 54 18 35 4 20 33 8 54 0 0 19 34 37 23 30 26 28 89 -35 19 1 50 20 7 25 18 35 35 20 33 39 55 0 0 19 34 47 23 30 28 29 90 -34 19 2 0 20 7 35 18 35 45 20 33 49 56 0 0 19 34 37 23 30 30 30 90 -33 19 1 49 20 7 25 18 35 35 20 33 39 57 0 0 19 34 6 23 30 31 31 90 -33 19 1 18 20 6 54 18 35 4 20 33 8 58 0 0 19 33 15 23 30 33 32 91 -32 19 0 27 20 6 2 18 34 12 20 32 17 59 0 0 19 32 3 23 30 35 33 91 -31 18 59 14 20 4 51 18 32 59 20 31 5 60 0 0 19 30 30 23 30 37 34 91 -30 18 57 42 20 3 19 18 31 26 20 29 33 61 0 0 19 28 37 23 30 39 35 92 -29 18 55 48 20 1 26 18 29 33 20 27 41 62 0 0 19 26 23 23 30 41 36 92 -28 18 53 34 19 59 13 18 27 18 20 25 28 63 0 0 19 23 49 23 30 43 37 92 -28 18 50 59 19 56 39 18 24 43 20 22 55 64 0 0 19 20 54 23 30 46 38 93 -27 18 48 4 19 53 45 18 21 47 20 20 1 65 0 0 19 17 39 23 30 48 39 93 -26 18 44 48 19 50 30 18 18 30 20 16 47 66 0 0 19 14 3 23 30 50 40 93 -25 18 41 11 19 46 55 18 14 53 20 13 13 67 0 0 19 10 7 23 30 52 41 94 -24 18 37 14 19 43 0 18 10 55 20 9 18 68 0 0 19 5 50 23 30 55 41 94 -23 18 32 56 19 38 44 18 6 37 20 5 3 69 0 0 19 1 13 23 30 57 42 94 -23 18 28 18 19 34 7 18 1 58 20 0 27 70 0 0 18 56 15 23 31 0 43 95 -22 18 23 19 19 29 10 17 56 58 19 55 31 71 0 0 18 50 57 23 31 2 44 95 -21 18 18 0 19 23 53 17 51 38 19 50 15 72 0 0 18 45 18 23 31 5 45 95 -20 18 12 20 19 18 16 17 45 57 19 44 38 73 0 0 18 39 19 23 31 7 46 96 -19 18 6 19 19 12 18 17 39 56 19 38 41 74 0 0 18 32 59 23 31 10 47 96 -18 17 59 59 19 6 0 17 33 34 19 32 24 75 0 0 18 26 19 23 31 13 48 96 -17 17 53 17 18 59 21 17 26 52 19 25 46 76 0 0 18 19 19 23 31 15 49 97 -16 17 46 16 18 52 22 17 19 49 19 18 49 77 0 0 18 11 59 23 31 18 50 97 -16 17 38 54 18 45 3 17 12 26 19 11 31 78 0 0 18 4 18 23 31 21 51 97 -15 17 31 12 18 37 24 17 4 42 19 3 53 79 0 0 17 56 17 23 31 24 52 98 -14 17 23 9 18 29 25 16 56 39 18 55 55 80 0 0 17 47 56 23 31 27 53 98 -13 17 14 47 18 21 6 16 48 15 18 47 37 81 0 0 17 39 15 23 31 30 54 98 -12 17 6 4 18 12 27 16 39 31 18 38 59 82 0 0 17 30 15 23 31 33 55 98 -11 16 57 2 18 3 27 16 30 27 18 30 2 83 0 0 17 20 54 23 31 36 56 99 -10 16 47 39 17 54 8 16 21 3 18 20 44 84 0 0 17 11 13 23 31 39 57 99 -9 16 37 56 17 44 29 16 11 19 18 11 7 85 0 0 17 1 13 23 31 42 58 99 -9 16 27 54 17 34 31 16 1 15 18 1 10 86 0 0 16 50 52 23 31 45 59 100 -8 16 17 32 17 24 13 15 50 51 17 50 53 87 0 0 16 40 13 23 31 49 60 100 -7 16 6 50 17 13 35 15 40 8 17 40 17 88 0 0 16 29 14 23 31 52 61 100 -6 15 55 49 17 2 38 15 29 5 17 29 21 89 0 0 16 17 55 23 31 55 62 100 -5 15 44 28 16 51 21 15 17 43 17 18 6 90 0 0 16 6 17 23 31 58 63 101 -4 15 32 48 16 39 46 15 6 1 17 6 32 91 0 0 15 54 20 23 32 2 64 101 -3 15 20 49 16 27 51 14 54 0 16 54 39 92 0 0 15 42 4 23 32 5 65 101 -2 15 8 31 16 15 37 14 41 40 16 42 27 93 0 0 15 29 29 23 32 9 66 101 -1 14 55 54 16 3 4 14 29 2 16 29 56 94 0 0 15 16 36 23 32 12 67 102 0 14 42 58 15 50 13 14 16 4 16 17 6 Uncertainty in time = +/- 2 secs [Prediction of 2008 Aug 12.0] Data for the target star ------------------------ * name: TYC 0704-01655-1 * constellation : Orion * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 05 22 00.9467 DE: +09 29 31.184 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .023, .021 ) * V mag [mag]: 11.4 * B mag [mag]: 11.9 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (176) Iduna approx. diameter [km]: 121 approx. diameter ["]: .057 distance from Earth [AU]: 2.91500 * orbital information: orbit source: Preston date of fit: 2008 Aug 11 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 892 number of rejected observations: 63 time covered by the observations: 1900 Nov 11 - 2008 Feb 10 1 sigma uncertainty ellipse (major, minor, PA): 0.017, 0.009, 97° remarks: * orbital elements for (176) Iduna : Mean anomaly = 24.52273961 deg Arg. of pericenter = 186.83127834 deg Long. of node = 200.72086471 deg Inclination = 22.58134263 deg Eccentricity = 0.16528236 Semimajor axis = 3.18816548 AU Perihelion dist = 2.66121797 AU Mag: H = 8.18, G = 0.15 Epoch of elements : MJD 54699.98200000 TDT (2008 Aug 21.982) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Aug 21 176 Iduna 23h 33.6m UT 11.4 5 22 0.947 9 29 31.18TYC 0704-01655-1 11.9 13.4 121 4.1 2.915 3.235 -15.10 116.4439 9.496 -172.67 11.73 23.5603 -0.00093 -0.00673 15.86358 -5.00188 -0.00514 -0.00083 2000 22.7944752008 812.00000186.831278200.720865 22.5813430.16528236 3.1881655 2.6612180 7.9 5.00.15 RATE 1.7313810 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.029 0.023 92 1.40 0.023 0 54690.5020080821_1655-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Aug 12, 02:29 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org