IOTA/IOTA-ES occultation update for (1585) Union / TYC 5777-01044-1 event on 2012 Aug 21, 07:05 UT Visible from Canada, W USA Summary ------- On 2012 Aug 21 UT, the 51 km diameter asteroid (1585) Union will occult a 10.6 mag star in the constellation Aquarius for observers along a path across Canada, W USA. In the case of an occultation, the combined light of the asteroid and the star will drop by 3.7 mag to 14.3 mag (the magnitude of the asteroid) for at most 3.3 seconds. This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Hugh Harris, historical astrometry from the MPC files (via AstDys), and the following catalogs for the star position: UCAC. The event at a glimpse ---------------------- * Rank: 61 * date and approx. time of event: 2012 Aug 21, 06:59 - 2012 Aug 21, 07:11 UT * geocentric midpoint of event [JD]: 2456160.795525 * magnitude of target star: 10.6 * magnitude drop [mag]: 3.7 * estimated maximum duration [s]: 3.3 * Moon: 16 % sunlit, 124° distance * Sun: 169° distance * rough path description: Canada, W USA The occultation path -------------------- * approximate projected width [km]: 59 * 1 sigma uncertainty interval [path widths]: +/- 1.01 * 1 sigma uncertainty interval [seconds]: +/- 3.3 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .043 +/- .040) * 1 sigma uncertainty ellipse (major, minor, PA): ( .044", .040", 95° ) * approx speed of asteroid's shadow [km/s]: 15.4396 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 5777-01044-1 by 1585 Union on 2012 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 ' " Longitude Longitude Longitude Longitude - 74 43 57 75 0 0 6 59 41 2 220 -1 - 76 5 17 - 73 21 24 - 78 46 15 - 70 30 30 Latitude Latitude Latitude Latitude - 76 0 0 74 36 33 6 59 41 3 218 -2 75 1 39 74 11 37 75 52 53 73 21 44 - 77 0 0 74 17 4 6 59 41 3 217 -2 74 42 33 73 51 45 75 34 35 73 1 9 - 78 0 0 73 56 40 6 59 41 3 217 -3 74 22 33 73 30 59 75 15 25 72 39 37 - 79 0 0 73 35 20 6 59 42 4 216 -3 74 1 37 73 9 15 74 55 19 72 17 7 - 80 0 0 73 12 59 6 59 42 4 215 -4 73 39 40 72 46 30 74 34 14 71 53 35 - 81 0 0 72 49 35 6 59 42 5 214 -4 73 16 41 72 22 41 74 12 8 71 28 58 - 82 0 0 72 25 4 6 59 42 5 213 -4 72 52 36 71 57 45 73 48 56 71 3 14 - 83 0 0 71 59 23 6 59 43 6 212 -5 72 27 22 71 31 39 73 24 36 70 36 19 - 84 0 0 71 32 30 6 59 43 6 211 -6 72 0 54 71 4 20 72 59 4 70 8 9 - 85 0 0 71 4 19 6 59 44 7 210 -6 71 33 10 70 35 43 72 32 17 69 38 42 - 86 0 0 70 34 47 6 59 45 8 209 -7 71 4 6 70 5 45 72 4 9 69 7 54 - 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0 16 39 -151 0 0 - 0 4 38 7 7 22 55 106 -44 0 16 30 - 0 25 40 0 59 29 - 1 7 51 -152 0 0 - 0 55 12 7 7 31 54 105 -43 - 0 34 18 - 1 16 0 0 8 12 - 1 57 43 -153 0 0 - 1 44 25 7 7 39 53 104 -42 - 1 23 45 - 2 4 59 - 0 41 43 - 2 46 16 -154 0 0 - 2 32 18 7 7 48 53 102 -42 - 2 11 51 - 2 52 39 - 1 30 17 - 3 33 30 -155 0 0 - 3 18 52 7 7 56 52 101 -41 - 2 58 38 - 3 39 1 - 2 17 30 - 4 19 26 -156 0 0 - 4 4 8 7 8 4 51 100 -40 - 3 44 6 - 4 24 4 - 3 3 24 - 5 4 5 -157 0 0 - 4 48 6 7 8 12 50 99 -39 - 4 28 16 - 5 7 50 - 3 47 58 - 5 47 28 -158 0 0 - 5 30 47 7 8 20 49 98 -39 - 5 11 9 - 5 50 20 - 4 31 15 - 6 29 35 -159 0 0 - 6 12 13 7 8 27 48 97 -38 - 5 52 46 - 6 31 35 - 5 13 15 - 7 10 28 -160 0 0 - 6 52 24 7 8 34 48 97 -37 - 6 33 8 - 7 11 35 - 5 53 59 - 7 50 7 -161 0 0 - 7 31 20 7 8 41 47 96 -36 - 7 12 15 - 7 50 21 - 6 33 28 - 8 28 33 -162 0 0 - 8 9 4 7 8 48 46 95 -35 - 7 50 9 - 8 27 55 - 7 11 42 - 9 5 46 -163 0 0 - 8 45 35 7 8 55 45 95 -34 - 8 26 50 - 9 4 17 - 7 48 43 - 9 41 49 -164 0 0 - 9 20 56 7 9 2 44 94 -33 - 9 2 20 - 9 39 28 - 8 24 32 -10 16 42 -165 0 0 - 9 55 6 7 9 8 43 94 -33 - 9 36 39 -10 13 29 - 8 59 10 -10 50 25 -166 0 0 -10 28 7 7 9 15 42 93 -32 -10 9 48 -10 46 21 - 9 32 37 -11 23 0 -167 0 0 -10 59 59 7 9 21 41 93 -31 -10 41 49 -11 18 5 -10 4 55 -11 54 28 -168 0 0 -11 30 44 7 9 27 40 93 -30 -11 12 42 -11 48 42 -10 36 5 -12 24 49 -169 0 0 -12 0 22 7 9 32 39 93 -29 -11 42 28 -12 18 12 -11 6 6 -12 54 4 -170 0 0 -12 28 54 7 9 38 38 92 -28 -12 11 7 -12 46 37 -11 35 1 -13 22 14 -171 0 0 -12 56 22 7 9 43 37 92 -27 -12 38 42 -13 13 58 -12 2 50 -13 49 21 -172 0 0 -13 22 45 7 9 49 37 92 -26 -13 5 12 -13 40 14 -12 29 35 -14 15 24 -173 0 0 -13 48 5 7 9 54 36 92 -26 -13 30 39 -14 5 28 -12 55 15 -14 40 25 -174 0 0 -14 12 23 7 9 59 35 92 -25 -13 55 3 -14 29 40 -13 19 51 -15 4 24 -175 0 0 -14 35 39 7 10 4 34 92 -24 -14 18 25 -14 52 50 -13 43 26 -15 27 22 -176 0 0 -14 57 54 7 10 8 33 92 -23 -14 40 45 -15 14 59 -14 5 58 -15 49 20 -177 0 0 -15 19 8 7 10 13 32 92 -22 -15 2 5 -15 36 8 -14 27 29 -16 10 19 -178 0 0 -15 39 24 7 10 17 31 92 -21 -15 22 26 -15 56 18 -14 48 0 -16 30 19 -179 0 0 -15 58 40 7 10 21 30 92 -20 -15 41 47 -16 15 30 -15 7 31 -16 49 20 -180 0 0 -16 16 58 7 10 26 29 92 -19 -16 0 9 -16 33 43 -15 26 3 -17 7 25 179 0 0 -16 34 18 7 10 30 28 92 -18 -16 17 34 -16 50 59 -15 43 37 -17 24 32 178 0 0 -16 50 41 7 10 33 27 92 -17 -16 34 1 -17 7 18 -16 0 12 -17 40 43 177 0 0 -17 6 8 7 10 37 26 92 -17 -16 49 32 -17 22 41 -16 15 51 -17 55 58 176 0 0 -17 20 38 7 10 41 25 93 -16 -17 4 6 -17 37 8 -16 30 32 -18 10 18 175 0 0 -17 34 13 7 10 44 24 93 -15 -17 17 44 -17 50 39 -16 44 17 -18 23 42 174 0 0 -17 46 53 7 10 47 23 93 -14 -17 30 27 -18 3 16 -16 57 6 -18 36 13 173 0 0 -17 58 37 7 10 50 23 93 -13 -17 42 14 -18 14 58 -17 9 0 -18 47 49 172 0 0 -18 9 28 7 10 53 22 93 -12 -17 53 8 -18 25 46 -17 19 59 -18 58 32 171 0 0 -18 19 24 7 10 56 21 94 -11 -18 3 7 -18 35 40 -17 30 2 -19 8 21 170 0 0 -18 28 27 7 10 59 20 94 -10 -18 12 12 -18 44 40 -17 39 12 -19 17 17 169 0 0 -18 36 37 7 11 2 19 94 -9 -18 20 23 -18 52 48 -17 47 27 -19 25 21 168 0 0 -18 43 53 7 11 4 18 94 -8 -18 27 41 -19 0 2 -17 54 48 -19 32 32 167 0 0 -18 50 16 7 11 7 17 95 -8 -18 34 5 -19 6 24 -18 1 16 -19 38 51 166 0 0 -18 55 46 7 11 9 16 95 -7 -18 39 37 -19 11 53 -18 6 50 -19 44 17 165 0 0 -19 0 24 7 11 11 15 95 -6 -18 44 15 -19 16 29 -18 11 31 -19 48 52 164 0 0 -19 4 9 7 11 13 14 95 -5 -18 48 1 -19 20 14 -18 15 18 -19 52 35 163 0 0 -19 7 1 7 11 15 13 96 -4 -18 50 54 -19 23 6 -18 18 12 -19 55 25 162 0 0 -19 9 1 7 11 17 12 96 -3 -18 52 55 -19 25 5 -18 20 13 -19 57 24 161 0 0 -19 10 9 7 11 18 11 96 -2 -18 54 2 -19 26 13 -18 21 21 -19 58 32 160 0 0 -19 10 24 7 11 20 10 97 -1 -18 54 17 -19 26 28 -18 21 36 -19 58 47 159 0 0 -19 9 46 7 11 21 10 97 0 -18 53 39 -19 25 51 -18 20 57 -19 58 11 Uncertainty in time = +/- 4 secs Prediction of 2012 Jul 3.0 Data for the target star ------------------------ * name: TYC 5777-01044-1 * constellation : Aquarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 21 19 13.3233 DE: -09 32 54.118 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .024, .036 ) * V mag [mag]: 10.6 * B mag [mag]: 11.6 * Apparent position with proper motion RA(deg): 319.9844890093 DE(deg): -9.4906687579 * Equation of equinoxes (radians) : 0.000071358448894 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (1585) Union approx. diameter [km]: 51 approx. diameter ["]: .042 distance from Earth [AU]: 1.69400 * orbital information: orbit source: Preston date of fit: 2012 Apr 08 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 997 number of rejected observations: 61 time covered by the observations: 1939 Feb 13 - 2011 Apr 29 1 sigma uncertainty ellipse (major, minor, PA): 0.036, 0.017, 97° remarks: * orbital elements for (1585) Union : Mean anomaly = 302.13882045 deg Arg. of pericenter = 264.79148831 deg Long. of node = 150.11663025 deg Inclination = 26.17402977 deg Eccentricity = 0.30885140 Semimajor axis = 2.92854657 AU Perihelion dist = 2.02406085 AU Mag: H = 10.21, G = 0.15 Epoch of elements : MJD 56160.29600000 TDT (2012 Aug 21.296) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Aug 21 1585 Union 7h 5.6m UT 10.6 21 19 13.323- 9 32 54.12TYC 5777-01044-1 11.6 14.3 51 3.3 1.694 -1.995 -34.30 -116.5949 -9.538 74.39 11.95 7.0926 -0.38919 0.33491 -5.68402 -6.60570 0.00105 -0.00025 2000 302.0806072012 821.00000264.791488150.116630 26.1740300.30885140 2.9285466 2.024060910.7 5.00.15 RATE 1.9666450 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.044 0.040 95 2.01 0.042 0 0 3 2 056111.0020120821_1044-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Jul 03, 01:17 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org