IOTA/IOTA-ES occultation update for (160) Una / 2UCAC 19742308 event on 2008 Jul 11, 02:59 UT Visible from SE Canada, NE USA Summary ------- On 2008 Jul 11 UT, the 81 km diameter asteroid (160) Una will occult a 12.3 mag star in the constellation Sagittarius for observers along a path across SE Canada, NE USA. In the case of an occultation, the combined light of the asteroid and the star will drop by 1.3 mag to 13.2 mag (the magnitude of the asteroid) for at most 7.4 seconds. This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Alice Monet, TMO astrometry for the asteroid kindly provided by Bill Owen, historical astrometry from the MPC files (via AstDys), and the following catalogs for the star position: UCAC. The event at a glimpse ---------------------- * Rank: 94 * date and approx. time of event: 2008 Jul 11, 02:56 - 2008 Jul 11, 03:02 UT * magnitude of target star: 12.3 * magnitude drop [mag]: 1.3 * estimated maximum duration [s]: 7.4 * Moon: 59 % sunlit, 61° distance * Sun: 162° distance * rough path description: SE Canada, NE USA Additional comments ------------------- low altitude The occultation path -------------------- * approximate projected width [km]: 293 * 1 sigma uncertainty interval [path widths]: +/- 0.45 * 1 sigma uncertainty interval [seconds]: +/- 3.3 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .030 +/- .027) * 1 sigma uncertainty ellipse (major, minor, PA): ( .030", .027", 90° ) * approx speed of asteroid's shadow [km/s]: 10.9720 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of 2UCAC 19742308 by 160 Una on 2008 Jul 11 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 - 87 33 36 58 0 0 3 2 3 1 159 -2 - 84 36 4 ... .. .. - 81 39 50 ... .. .. - 86 43 28 57 0 0 3 2 2 2 159 -3 - 83 45 53 - 89 26 17 - 80 48 57 ... .. .. - 85 46 51 56 0 0 3 2 0 3 160 -4 - 82 48 11 - 88 30 3 - 79 49 13 ... .. .. - 84 43 27 55 0 0 3 1 58 4 161 -6 - 81 42 31 - 87 27 55 - 78 39 58 ... .. .. - 83 32 53 54 0 0 3 1 55 5 162 -7 - 80 28 15 - 86 19 35 - 77 20 9 ... .. .. - 82 14 27 53 0 0 3 1 50 6 163 -8 - 79 4 21 - 85 4 36 - 75 48 3 - 87 25 16 - 80 47 14 52 0 0 3 1 44 7 164 -9 - 77 29 18 - 83 42 19 - 74 0 56 - 86 6 1 - 79 9 51 51 0 0 3 1 37 9 166 -11 - 75 40 43 - 82 11 50 - 71 54 3 - 84 39 44 - 77 20 11 50 0 0 3 1 28 10 167 -12 - 73 34 38 - 80 31 48 - 69 18 7 - 83 5 29 - 75 14 58 49 0 0 3 1 17 11 169 -14 - 71 3 54 - 78 40 20 - 65 49 47 - 81 21 58 Latitude Latitude Latitude Latitude - 75 0 0 48 53 23 3 1 15 11 169 -14 50 39 34 47 19 53 52 31 55 46 3 27 - 74 0 0 48 28 0 3 1 9 12 170 -15 50 11 19 46 56 28 51 59 31 45 41 22 - 73 0 0 48 4 21 3 1 3 12 171 -15 49 45 9 46 34 35 51 29 49 45 20 41 - 72 0 0 47 42 22 3 0 57 13 172 -16 49 20 56 46 14 10 51 2 35 45 1 22 - 71 0 0 47 21 59 3 0 51 13 173 -17 48 58 36 45 55 12 50 37 36 44 43 23 - 70 0 0 47 3 10 3 0 45 14 173 -17 48 38 3 45 37 39 50 14 45 44 26 42 - 69 0 0 46 45 51 3 0 38 14 174 -18 48 19 12 45 21 28 49 53 54 44 11 19 - 68 0 0 46 30 0 3 0 32 14 175 -18 48 1 59 45 6 37 49 34 58 43 57 12 - 67 0 0 46 15 36 3 0 25 15 176 -19 47 46 23 44 53 6 49 17 50 43 44 19 - 66 0 0 46 2 35 3 0 18 15 177 -19 47 32 19 44 40 53 49 2 27 43 32 40 - 65 0 0 45 50 57 3 0 12 15 178 -20 47 19 47 44 29 57 48 48 46 43 22 14 - 64 0 0 45 40 41 3 0 5 15 179 -20 47 8 43 44 20 17 48 36 43 43 12 59 - 63 0 0 45 31 45 2 59 58 15 179 -20 46 59 7 44 11 52 48 26 17 43 4 57 - 62 0 0 45 24 9 2 59 51 16 180 -21 46 50 56 44 4 41 48 17 25 42 58 5 - 61 0 0 45 17 51 2 59 44 16 181 -21 46 44 11 43 58 45 48 10 6 42 52 24 - 60 0 0 45 12 51 2 59 37 16 182 -21 46 38 49 43 54 2 48 4 18 42 47 53 - 59 0 0 45 9 9 2 59 30 16 183 -21 46 34 51 43 50 31 48 0 1 42 44 31 - 58 0 0 45 6 44 2 59 23 16 184 -22 46 32 16 43 48 14 47 57 13 42 42 20 - 57 0 0 45 5 35 2 59 16 16 185 -22 46 31 3 43 47 9 47 55 55 42 41 17 - 56 0 0 45 5 44 2 59 9 16 186 -22 46 31 13 43 47 17 47 56 6 42 41 25 - 55 0 0 45 7 9 2 59 2 16 187 -22 46 32 45 43 48 37 47 57 46 42 42 41 - 54 0 0 45 9 52 2 58 55 15 187 -22 46 35 39 43 51 10 48 0 55 42 45 7 - 53 0 0 45 13 52 2 58 49 15 188 -22 46 39 57 43 54 56 48 5 35 42 48 43 - 52 0 0 45 19 10 2 58 42 15 189 -22 46 45 39 43 59 56 48 11 45 42 53 29 - 51 0 0 45 25 46 2 58 35 15 190 -22 46 52 45 44 6 9 48 19 28 42 59 26 - 50 0 0 45 33 41 2 58 29 15 191 -22 47 1 16 44 13 36 48 28 44 43 6 33 - 49 0 0 45 42 56 2 58 22 14 192 -22 47 11 14 44 22 18 48 39 35 43 14 51 - 48 0 0 45 53 32 2 58 16 14 193 -22 47 22 41 44 32 16 48 52 4 43 24 22 - 47 0 0 46 5 30 2 58 9 14 193 -22 47 35 37 44 43 31 49 6 12 43 35 5 - 46 0 0 46 18 52 2 58 3 13 194 -22 47 50 5 44 56 3 49 22 4 43 47 1 - 45 0 0 46 33 39 2 57 57 13 195 -22 48 6 8 45 9 54 49 39 43 44 0 12 - 44 0 0 46 49 54 2 57 51 12 196 -21 48 23 47 45 25 5 49 59 13 44 14 39 - 43 0 0 47 7 37 2 57 45 12 197 -21 48 43 8 45 41 38 50 20 39 44 30 22 - 42 0 0 47 26 53 2 57 40 11 198 -21 49 4 13 45 59 35 50 44 9 44 47 23 - 41 0 0 47 47 44 2 57 35 11 198 -20 49 27 7 46 18 57 51 9 49 45 5 44 - 40 0 0 48 10 13 2 57 29 10 199 -20 49 51 55 46 39 47 51 37 51 45 25 26 - 39 0 0 48 34 24 2 57 24 10 200 -19 50 18 45 47 2 8 52 8 25 45 46 32 - 38 0 0 49 0 22 2 57 20 9 201 -19 50 47 44 47 26 2 52 41 48 46 9 3 - 37 0 0 49 28 12 2 57 15 8 202 -18 51 19 2 47 51 34 53 18 20 46 33 2 - 36 0 0 49 58 1 2 57 11 8 203 -18 51 52 51 48 18 47 53 58 29 46 58 31 - 35 0 0 50 29 57 2 57 7 7 203 -17 52 29 26 48 47 45 54 42 54 47 25 35 - 34 0 0 51 4 9 2 57 3 6 204 -17 53 9 8 49 18 35 55 32 34 47 54 17 - 33 0 0 51 40 49 2 57 0 5 205 -16 53 52 25 49 51 23 56 29 2 48 24 41 - 32 0 0 52 20 12 2 56 57 5 206 -15 54 39 52 50 26 16 .. .. .. 48 56 52 - 31 0 0 53 2 36 2 56 55 4 207 -14 55 32 27 51 3 25 .. .. .. 49 30 57 - 30 0 0 53 48 28 2 56 53 3 207 -13 56 31 36 51 43 1 .. .. .. 50 7 1 - 29 0 0 54 38 22 2 56 52 2 208 -13 .. .. .. 52 25 19 .. .. .. 50 45 14 - 28 0 0 55 33 9 2 56 51 1 209 -12 .. .. .. 53 10 37 .. .. .. .. .. .. Uncertainty in time = +/- 4 secs [Prediction of 2008 Jul 2.0] Data for the target star ------------------------ * name: 2UCAC 19742308 * constellation : Sagittarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 18 07 12.2518 DE: -29 15 10.208 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .022, .022 ) * V mag [mag]: 12.3 * B mag [mag]: 0.0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (160) Una approx. diameter [km]: 81 approx. diameter ["]: .059 distance from Earth [AU]: 1.88200 * orbital information: orbit source: Preston date of fit: 2008 Jul 02 source of used astrometry: FASTT TMO MPC (via Astdys) number of used observations: 874 number of rejected observations: 134 time covered by the observations: 1910 Oct 12 - 2008 Jun 12 1 sigma uncertainty ellipse (major, minor, PA): 0.021, 0.015, 90° remarks: * orbital elements for (160) Una : Mean anomaly = 223.93635632 deg Arg. of pericenter = 49.94301429 deg Long. of node = 8.76255685 deg Inclination = 3.82131631 deg Eccentricity = 0.06560426 Semimajor axis = 2.73008796 AU Perihelion dist = 2.55098256 AU Mag: H = 9.02, G = 0.15 Epoch of elements : MJD 54658.12400000 TDT (2008 Jul 11.124) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Jul 11 160 Una 2h 59.4m UT 12.3 18 7 12.252-29 15 10.212UCAC 19742308 0.0 13.2 81 7.4 1.882 -2.208 1.40 -62.4597 -29.252 136.52 22.07 2.9908 0.04646 0.95982 -6.18570 0.29885 0.00169 0.00056 2000 222.1613122008 7 3.00000 49.943014 8.762557 3.8213160.06560426 2.7300880 2.5509826 9.1 5.00.15 RATE 2.1849380 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.030 0.027 90 1.45 0.027 0 54649.5020080711_742308 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Jul 02, 19:23 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org