IOTA/IOTA-ES occultation update for (1585) Union / TYC 6350-01488-1 event on 2007 Oct 04, 02:08 UT Visible from W Africa Summary ------- On 2007 Oct 04 UT, the 50 km diameter asteroid (1585) Union will occult a 9.8 mag star in the constellation Capricornus for observers along a path across W Africa. In the case of an occultation, the combined light of the asteroid and the star will drop by 5.1 mag to 14.9 mag (the magnitude of the asteroid) for at most 6.3 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: 68 * date and approx. time of event: 2007 Oct 04, 02:05 - 2007 Oct 04, 02:12 UT * midpoint of event [JD]: 2454377.5893625 * magnitude of target star: 9.8 * magnitude drop [mag]: 5.1 * estimated maximum duration [s]: 6.3 * Moon: 43 % sunlit, 155° distance * Sun: 124° distance * rough path description: W Africa The occultation path -------------------- * approximate projected width [km]: 187 * 1 sigma uncertainty interval [path widths]: +/- 0.87 * 1 sigma uncertainty interval [seconds]: +/- 4.3 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .032 +/- .026) * 1 sigma uncertainty ellipse (major, minor, PA): ( .033", .025", 101° ) * approx speed of asteroid's shadow [km/s]: 7.9604 * website for maps: http://lunar-occultations.com/iota/asteroids/astrndx.htm http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 6350-01488-1 by 1585 Union on 2007 Oct 04 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 - 3 55 51 18 0 0 2 5 9 1 250 -57 ... .. .. ... .. .. ... .. .. ... .. .. - 5 52 52 17 0 0 2 5 13 3 249 -60 - 7 21 14 - 4 4 38 ... .. .. ... .. .. - 7 21 6 16 0 0 2 5 19 5 249 -61 - 8 37 42 - 5 52 40 - 10 33 6 - 2 16 59 - 8 32 14 15 0 0 2 5 27 6 249 -63 - 9 41 18 - 7 14 53 - 11 27 50 - 4 25 59 - 9 31 25 14 0 0 2 5 35 8 249 -64 - 10 35 12 - 8 21 16 - 12 15 9 - 5 55 42 - 10 21 25 13 0 0 2 5 45 9 249 -65 - 11 21 18 - 9 16 21 - 12 56 12 - 7 5 15 - 11 3 58 12 0 0 2 5 54 10 249 -66 - 12 0 53 - 10 2 39 - 13 31 49 - 8 1 28 - 11 40 12 11 0 0 2 6 5 10 249 -67 - 12 34 49 - 10 41 45 - 14 2 37 - 8 47 42 - 12 10 57 10 0 0 2 6 16 11 249 -67 - 13 3 45 - 11 14 41 - 14 29 2 - 9 25 58 - 12 36 45 9 0 0 2 6 27 12 249 -68 - 13 28 8 - 11 42 11 - 14 51 26 - 9 57 29 - 12 58 3 8 0 0 2 6 38 13 249 -68 - 13 48 20 - 12 4 48 - 15 10 4 - 10 23 7 - 13 15 8 7 0 0 2 6 50 13 249 -69 - 14 4 36 - 12 22 52 - 15 25 9 - 10 43 25 - 13 28 15 6 0 0 2 7 3 14 249 -69 - 14 17 7 - 12 36 40 - 15 36 49 - 10 58 47 - 13 37 32 5 0 0 2 7 15 14 249 -69 - 14 26 2 - 12 46 24 - 15 45 11 - 11 9 30 - 13 43 6 4 0 0 2 7 28 15 250 -69 - 14 31 25 - 12 52 9 - 15 50 18 - 11 15 42 - 13 44 58 3 0 0 2 7 41 15 250 -69 - 14 33 18 - 12 54 0 - 15 52 12 - 11 17 29 - 13 43 8 2 0 0 2 7 55 15 250 -69 - 14 31 41 - 12 51 55 - 15 50 54 - 11 14 49 - 13 37 34 1 0 0 2 8 9 15 250 -69 - 14 26 32 - 12 45 51 - 15 46 20 - 11 7 36 - 13 28 8 0 0 0 2 8 23 15 251 -68 - 14 17 44 - 12 35 39 - 15 38 27 - 10 55 39 - 13 14 40 - 1 0 0 2 8 37 16 251 -68 - 14 5 9 - 12 21 7 - 15 27 8 - 10 38 39 - 12 56 54 - 2 0 0 2 8 52 15 251 -67 - 13 48 35 - 12 1 57 - 15 12 12 - 10 16 10 - 12 34 32 - 3 0 0 2 9 7 15 252 -66 - 13 27 43 - 11 37 44 - 14 53 27 - 9 47 30 - 12 7 3 - 4 0 0 2 9 22 15 252 -66 - 13 2 12 - 11 7 51 - 14 30 36 - 9 11 42 - 11 33 50 - 5 0 0 2 9 38 15 252 -65 - 12 31 30 - 10 31 30 - 14 3 16 - 8 27 14 Latitude Latitude Latitude Latitude - 11 0 0 - 5 51 36 2 9 52 15 252 -64 - 7 14 6 - 4 13 59 - 9 16 16 0 19 10 - 10 0 0 - 7 6 54 2 10 14 14 253 -62 - 8 19 56 - 5 44 2 -10 11 26 - 2 35 31 - 9 0 0 - 8 7 31 2 10 32 13 253 -61 - 9 14 13 - 6 53 36 -10 58 1 - 4 17 5 - 8 0 0 - 8 57 22 2 10 47 12 253 -60 - 9 59 31 - 7 49 30 -11 37 33 - 5 31 8 - 7 0 0 - 9 38 41 2 11 1 12 253 -58 -10 37 27 - 8 35 10 -12 11 0 - 6 28 39 - 6 0 0 -10 12 54 2 11 13 11 253 -57 -11 9 4 - 9 12 38 -12 39 8 - 7 14 27 - 5 0 0 -10 41 1 2 11 24 10 253 -56 -11 35 10 - 9 43 12 -13 2 28 - 7 51 7 - 4 0 0 -11 3 41 2 11 33 9 253 -55 -11 56 17 -10 7 47 -13 21 24 - 8 20 13 - 3 0 0 -11 21 26 2 11 42 8 253 -54 -12 12 49 -10 26 58 -13 36 15 - 8 42 47 - 2 0 0 -11 34 37 2 11 49 7 252 -53 -12 25 5 -10 41 13 -13 47 14 - 8 59 32 - 1 0 0 -11 43 28 2 11 55 6 252 -52 -12 33 18 -10 50 51 .. .. .. - 9 10 54 0 0 0 -11 48 11 2 12 1 6 252 -51 -12 37 36 -10 56 3 .. .. .. - 9 17 14 1 0 0 -11 48 53 2 12 5 5 252 -50 -12 38 5 -10 56 59 .. .. .. - 9 18 42 2 0 0 -11 45 36 2 12 9 4 252 -49 -12 34 49 -10 53 42 .. .. .. - 9 15 25 3 0 0 -11 38 20 2 12 12 3 252 -48 .. .. .. -10 46 12 .. .. .. - 9 7 21 4 0 0 -11 27 3 2 12 14 2 251 -47 .. .. .. -10 34 24 .. .. .. - 8 54 26 5 0 0 -11 11 37 2 12 15 1 251 -47 .. .. .. -10 18 12 .. .. .. .. .. .. Data for the target star ------------------------ * name: TYC 6350-01488-1 * constellation : Capricornus * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 21 08 56.4328 DE: -18 37 24.984 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .019, .019 ) * V mag [mag]: 9.8 * B mag [mag]: 10.2 * Apparent position with proper motion RA(deg): 317.3500119116 DE(deg): -18.5922413553 * Equation of equinoxes (radians) : 0.000029955111591 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (1585) Union approx. diameter [km]: 50 approx. diameter ["]: .037 distance from Earth [AU]: 1.83900 * orbital information: orbit source: Preston date of fit: 2007 Aug 29 source of used astrometry: FASTT TMO MPC (via Astdys) number of used observations: 704 number of rejected observations: 60 time covered by the observations: 1939 Feb 13 - 2007 Aug 08 1 sigma uncertainty ellipse (major, minor, PA): 0.027, 0.017, 106° remarks: * orbital elements for (1585) Union : Mean anomaly = 311.89044424 deg Arg. of pericenter = 264.70921474 deg Long. of node = 150.15095917 deg Inclination = 26.16821671 deg Eccentricity = 0.30735418 Semimajor axis = 2.93065095 AU Perihelion dist = 2.02990314 AU Mag: H = 10.16, G = 0.15 Epoch of elements : MJD 54377.09000000 TDT (2007 Oct 04.090) ------ occelmnt file for Occult BEGIN ----------------------------------- 2007 Oct 04 1585 Union 2h 8.7m UT 9.8 21 8 56.433-18 37 24.98TYC 6350-01488-1 10.2 14.9 50 6.3 1.839 0.106 -21.43 272.670 -18.618 145.07 -4.15 2.1447 .96123 .06687 0.30950 -4.48241 0.00444 0.00148 2000 310.4975942007 927.00000264.709215150.150959 26.1682170.307354182.930650952.0299031410.65 0.15 RATE 1.9645270 .0000000 .0000000 .0000000 .00000000 .00000000 .00000000 Meas 0.033 0.025 100.9 1.870 0.033 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2007 Sep 03, 06:03 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org