IOTA/IOTA-ES occultation update for (1585) Union / TYC 0211-00321-1 event on 2008 Oct 12, 07:39 UT Visible from SE USA Summary ------- On 2008 Oct 12 UT, the 50 km diameter asteroid (1585) Union will occult a 11.0 mag star in the constellation Hydra for observers along a path across SE USA. In the case of an occultation, the combined light of the asteroid and the star will drop by 4.4 mag to 15.4 mag (the magnitude of the asteroid) for at most 1.9 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: 60 * date and approx. time of event: 2008 Oct 12, 07:36 - 2008 Oct 12, 07:38 UT * midpoint of event [JD]: 2454751.819425 * magnitude of target star: 11.0 * magnitude drop [mag]: 4.4 * estimated maximum duration [s]: 1.9 * Moon: 92 % sunlit, 143° distance * Sun: 68° distance * rough path description: SE USA The occultation path -------------------- * approximate projected width [km]: 53 * 1 sigma uncertainty interval [path widths]: +/- 1.03 * 1 sigma uncertainty interval [seconds]: +/- 2.0 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .033 +/- .029) * 1 sigma uncertainty ellipse (major, minor, PA): ( .033", .029", 79° ) * approx speed of asteroid's shadow [km/s]: 27.1156 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 0211-00321-1 by 1585 Union on 2008 Oct 12 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 - 95 0 0 32 40 24 7 36 16 1 90 -57 32 26 4 32 54 46 31 56 36 33 24 25 - 94 0 0 32 40 20 7 36 16 1 91 -57 32 26 0 32 54 41 31 56 31 33 24 20 - 93 0 0 32 40 2 7 36 17 2 91 -56 32 25 42 32 54 24 31 56 14 33 24 3 - 92 0 0 32 39 32 7 36 17 3 92 -56 32 25 12 32 53 54 31 55 43 33 23 32 - 91 0 0 32 38 49 7 36 17 4 92 -55 32 24 28 32 53 10 31 55 0 33 22 49 - 90 0 0 32 37 53 7 36 17 5 93 -54 32 23 32 32 52 14 31 54 4 33 21 53 - 89 0 0 32 36 44 7 36 18 6 93 -54 32 22 23 32 51 5 31 52 55 33 20 44 - 88 0 0 32 35 22 7 36 18 7 94 -53 32 21 1 32 49 44 31 51 32 33 19 23 - 87 0 0 32 33 47 7 36 18 7 95 -52 32 19 26 32 48 9 31 49 57 33 17 48 - 86 0 0 32 31 59 7 36 19 8 95 -52 32 17 39 32 46 21 31 48 9 33 16 1 - 85 0 0 32 29 59 7 36 19 9 96 -51 32 15 38 32 44 21 31 46 9 33 14 1 - 84 0 0 32 27 46 7 36 20 10 96 -50 32 13 25 32 42 8 31 43 55 33 11 48 - 83 0 0 32 25 19 7 36 21 11 97 -50 32 10 58 32 39 42 31 41 28 33 9 22 - 82 0 0 32 22 40 7 36 21 12 97 -49 32 8 19 32 37 3 31 38 48 33 6 44 - 81 0 0 32 19 49 7 36 22 12 98 -48 32 5 27 32 34 11 31 35 56 33 3 53 - 80 0 0 32 16 44 7 36 23 13 98 -47 32 2 22 32 31 7 31 32 51 33 0 49 - 79 0 0 32 13 26 7 36 24 14 99 -47 31 59 4 32 27 50 31 29 33 32 57 32 - 78 0 0 32 9 56 7 36 25 15 99 -46 31 55 34 32 24 20 31 26 2 32 54 2 - 77 0 0 32 6 13 7 36 26 16 100 -45 31 51 51 32 20 37 31 22 18 32 50 20 - 76 0 0 32 2 17 7 36 27 17 101 -44 31 47 55 32 16 41 31 18 21 32 46 25 - 75 0 0 31 58 9 7 36 28 18 101 -44 31 43 46 32 12 33 31 14 12 32 42 17 - 74 0 0 31 53 48 7 36 29 18 102 -43 31 39 24 32 8 12 31 9 50 32 37 57 - 73 0 0 31 49 14 7 36 30 19 102 -42 31 34 50 32 3 39 31 5 15 32 33 24 - 72 0 0 31 44 28 7 36 32 20 103 -41 31 30 4 31 58 53 31 0 28 32 28 39 - 71 0 0 31 39 29 7 36 33 21 103 -41 31 25 4 31 53 54 30 55 28 32 23 41 - 70 0 0 31 34 17 7 36 34 22 104 -40 31 19 53 31 48 43 30 50 15 32 18 31 - 69 0 0 31 28 53 7 36 36 23 104 -39 31 14 28 31 43 19 30 44 50 32 13 8 - 68 0 0 31 23 17 7 36 37 24 105 -38 31 8 51 31 37 43 30 39 13 32 7 32 - 67 0 0 31 17 28 7 36 39 24 106 -37 31 3 2 31 31 55 30 33 23 32 1 45 - 66 0 0 31 11 26 7 36 40 25 106 -37 30 57 0 31 25 54 30 27 20 31 55 44 - 65 0 0 31 5 13 7 36 42 26 107 -36 30 50 47 31 19 41 30 21 6 31 49 32 - 64 0 0 30 58 47 7 36 44 27 107 -35 30 44 20 31 13 15 30 14 39 31 43 8 - 63 0 0 30 52 9 7 36 45 28 108 -34 30 37 42 31 6 38 30 7 59 31 36 31 - 62 0 0 30 45 19 7 36 47 29 109 -33 30 30 51 30 59 48 30 1 8 31 29 42 - 61 0 0 30 38 17 7 36 49 30 109 -32 30 23 49 30 52 46 29 54 4 31 22 41 - 60 0 0 30 31 3 7 36 51 30 110 -32 30 16 34 30 45 32 29 46 49 31 15 28 - 59 0 0 30 23 36 7 36 53 31 110 -31 30 9 8 30 38 7 29 39 21 31 8 4 - 58 0 0 30 15 59 7 36 55 32 111 -30 30 1 29 30 30 29 29 31 42 31 0 27 - 57 0 0 30 8 9 7 36 57 33 112 -29 29 53 39 30 22 40 29 23 51 30 52 39 - 56 0 0 30 0 7 7 36 59 34 112 -28 29 45 37 30 14 39 29 15 48 30 44 39 - 55 0 0 29 51 54 7 37 1 35 113 -27 29 37 23 30 6 26 29 7 33 30 36 27 - 54 0 0 29 43 30 7 37 3 36 114 -27 29 28 58 29 58 2 28 59 7 30 28 4 - 53 0 0 29 34 54 7 37 6 36 114 -26 29 20 22 29 49 27 28 50 30 30 19 29 - 52 0 0 29 26 6 7 37 8 37 115 -25 29 11 34 29 40 40 28 41 41 30 10 44 - 51 0 0 29 17 8 7 37 10 38 116 -24 29 2 35 29 31 42 28 32 41 30 1 46 - 50 0 0 29 7 58 7 37 13 39 116 -23 28 53 25 29 22 33 28 23 30 29 52 38 - 49 0 0 28 58 37 7 37 15 40 117 -22 28 44 4 29 13 12 28 14 8 29 43 19 - 48 0 0 28 49 6 7 37 18 41 118 -21 28 34 32 29 3 41 28 4 35 29 33 49 - 47 0 0 28 39 23 7 37 20 42 118 -21 28 24 49 28 53 59 27 54 51 29 24 8 - 46 0 0 28 29 30 7 37 23 42 119 -20 28 14 55 28 44 7 27 44 56 29 14 17 - 45 0 0 28 19 27 7 37 26 43 120 -19 28 4 51 28 34 4 27 34 51 29 4 15 - 44 0 0 28 9 13 7 37 28 44 121 -18 27 54 37 28 23 51 27 24 36 28 54 2 - 43 0 0 27 58 49 7 37 31 45 122 -17 27 44 12 28 13 27 27 14 10 28 43 40 - 42 0 0 27 48 15 7 37 34 46 122 -16 27 33 37 28 2 53 27 3 34 28 33 7 - 41 0 0 27 37 30 7 37 37 47 123 -15 27 22 53 27 52 9 26 52 49 28 22 24 - 40 0 0 27 26 36 7 37 40 48 124 -14 27 11 58 27 41 16 26 41 53 28 11 32 - 39 0 0 27 15 33 7 37 43 48 125 -13 27 0 54 27 30 13 26 30 48 28 0 30 - 38 0 0 27 4 19 7 37 46 49 126 -12 26 49 40 27 19 0 26 19 33 27 49 18 - 37 0 0 26 52 57 7 37 49 50 127 -12 26 38 17 27 7 38 26 8 9 27 37 57 - 36 0 0 26 41 25 7 37 52 51 128 -11 26 26 45 26 56 7 25 56 36 27 26 27 - 35 0 0 26 29 45 7 37 55 52 129 -10 26 15 4 26 44 27 25 44 54 27 14 47 - 34 0 0 26 17 55 7 37 58 53 130 -9 26 3 14 26 32 38 25 33 4 27 2 59 - 33 0 0 26 5 57 7 38 2 53 131 -8 25 51 16 26 20 40 25 21 4 26 51 3 - 32 0 0 25 53 51 7 38 5 54 132 -7 25 39 9 26 8 34 25 8 57 26 38 58 - 31 0 0 25 41 36 7 38 8 55 133 -6 25 26 54 25 56 20 24 56 41 26 26 45 - 30 0 0 25 29 14 7 38 12 56 134 -5 25 14 31 25 43 58 24 44 17 26 14 23 - 29 0 0 25 16 43 7 38 15 57 135 -4 25 2 0 25 31 28 24 31 45 26 1 54 - 28 0 0 25 4 6 7 38 18 57 136 -3 24 49 22 25 18 50 24 19 6 25 49 17 - 27 0 0 24 51 20 7 38 22 58 137 -2 24 36 36 25 6 5 24 6 20 25 36 33 - 26 0 0 24 38 28 7 38 25 59 139 -1 24 23 44 24 53 13 23 53 26 25 23 42 - 25 0 0 24 25 28 7 38 29 60 140 0 24 10 44 24 40 14 23 40 26 25 10 44 Uncertainty in time = +/- 2 secs [Prediction of 2008 Sep 11.0] Data for the target star ------------------------ * name: TYC 0211-00321-1 * constellation : Hydra * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 08 38 14.8501 DE: +00 12 46.321 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .022, .022 ) * V mag [mag]: 11.0 * B mag [mag]: 12.4 * Apparent position with proper motion RA(deg): 129.6756845253 DE(deg): 0.1845532479 * Equation of equinoxes (radians) : 0.000048670109656 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (1585) Union approx. diameter [km]: 50 approx. diameter ["]: .029 distance from Earth [AU]: 2.36100 * orbital information: orbit source: Preston date of fit: 2008 Aug 06 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 827 number of rejected observations: 60 time covered by the observations: 1939 Feb 13 - 2007 Nov 29 1 sigma uncertainty ellipse (major, minor, PA): 0.025, 0.019, 71° remarks: * orbital elements for (1585) Union : Mean anomaly = 25.39925785 deg Arg. of pericenter = 264.71561982 deg Long. of node = 150.14703272 deg Inclination = 26.16842339 deg Eccentricity = 0.30755845 Semimajor axis = 2.93135720 AU Perihelion dist = 2.02979353 AU Mag: H = 10.17, G = 0.15 Epoch of elements : MJD 54751.31900000 TDT (2008 Oct 12.319) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Oct 12 1585 Union 7h 40.0m UT 11.0 8 38 14.850 0 12 46.32TYC 0211-00321-1 12.4 15.4 50 1.9 2.361 3.700 -13.00 -6.6878 0.217 61.62 -7.58 7.6662 0.07641 0.32154 14.90170 -3.48954 -0.00503 0.00073 2000 25.14023120081011.00000264.715620150.147033 26.1684230.30755845 2.9313572 2.029793510.7 5.00.15 RATE 1.9638160 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.033 0.029 79 2.03 0.030 0 54720.5020081012_0321-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Sep 11, 16:32 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org