IOTA/IOTA-ES occultation update for (666) Desdemona / TYC 5764-01436-1 event on 2008 Dec 05, 19:06 UT Visible from Africa Summary ------- On 2008 Dec 05 UT, the 27 km diameter asteroid (666) Desdemona will occult a 10.3 mag star in the constellation Aquarius for observers along a path across Africa. In the case of an occultation, the combined light of the asteroid and the star will drop by 5.4 mag to 15.7 mag (the magnitude of the asteroid) for at most 0.8 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: 45 * date and approx. time of event: 2008 Dec 05, 19:08 - 2008 Dec 05, 19:09 UT * magnitude of target star: 10.3 * magnitude drop [mag]: 5.4 * estimated maximum duration [s]: 0.8 * Moon: 49 % sunlit, 33° distance * Sun: 57° distance * rough path description: Africa The occultation path -------------------- * approximate projected width [km]: 29 * 1 sigma uncertainty interval [path widths]: +/- 1.46 * 1 sigma uncertainty interval [seconds]: +/- 1.3 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .025 +/- .022) * 1 sigma uncertainty ellipse (major, minor, PA): ( .025", .022", 86° ) * approx speed of asteroid's shadow [km/s]: 35.5063 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 5764-01436-1 by 666 Desdemona on 2008 Dec 5 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 - 9 0 0 -21 44 30 19 8 44 49 276 -1 -21 52 35 -21 36 25 -22 16 14 -21 12 52 - 8 0 0 -21 27 34 19 8 47 48 276 -2 -21 35 39 -21 19 29 -21 59 18 -20 55 55 - 7 0 0 -21 10 33 19 8 49 47 275 -3 -21 18 39 -21 2 28 -21 42 18 -20 38 54 - 6 0 0 -20 53 29 19 8 51 46 274 -4 -21 1 34 -20 45 24 -21 25 14 -20 21 50 - 5 0 0 -20 36 22 19 8 54 45 273 -5 -20 44 27 -20 28 16 -21 8 7 -20 4 42 - 4 0 0 -20 19 11 19 8 56 44 273 -6 -20 27 17 -20 11 6 -20 50 57 -19 47 32 - 3 0 0 -20 1 58 19 8 58 43 272 -7 -20 10 4 -19 53 53 -20 33 45 -19 30 19 - 2 0 0 -19 44 44 19 9 1 43 271 -8 -19 52 49 -19 36 38 -20 16 30 -19 13 4 - 1 0 0 -19 27 27 19 9 3 42 271 -9 -19 35 32 -19 19 21 -19 59 13 -18 55 47 0 0 0 -19 10 9 19 9 5 41 270 -10 -19 18 14 -19 2 3 -19 41 55 -18 38 29 1 0 0 -18 52 49 19 9 7 40 270 -11 -19 0 55 -18 44 44 -19 24 36 -18 21 10 2 0 0 -18 35 30 19 9 9 39 269 -12 -18 43 35 -18 27 24 -19 7 16 -18 3 50 3 0 0 -18 18 10 19 9 11 38 269 -13 -18 26 15 -18 10 4 -18 49 55 -17 46 30 4 0 0 -18 0 50 19 9 13 37 268 -14 -18 8 55 -17 52 45 -18 32 35 -17 29 10 5 0 0 -17 43 30 19 9 15 36 268 -15 -17 51 36 -17 35 25 -18 15 16 -17 11 51 6 0 0 -17 26 12 19 9 17 35 267 -15 -17 34 17 -17 18 7 -17 57 57 -16 54 33 7 0 0 -17 8 55 19 9 19 34 267 -16 -17 17 0 -17 0 50 -17 40 39 -16 37 17 8 0 0 -16 51 39 19 9 21 33 266 -17 -16 59 44 -16 43 35 -17 23 23 -16 20 2 9 0 0 -16 34 26 19 9 23 32 266 -18 -16 42 31 -16 26 21 -17 6 9 -16 2 49 10 0 0 -16 17 15 19 9 24 31 265 -19 -16 25 20 -16 9 11 -16 48 58 -15 45 38 11 0 0 -16 0 7 19 9 26 30 265 -20 -16 8 12 -15 52 3 -16 31 49 -15 28 31 12 0 0 -15 43 2 19 9 28 29 265 -21 -15 51 7 -15 34 58 -16 14 44 -15 11 27 13 0 0 -15 26 1 19 9 29 28 264 -22 -15 34 5 -15 17 57 -15 57 42 -14 54 26 14 0 0 -15 9 4 19 9 31 27 264 -23 -15 17 8 -15 1 0 -15 40 44 -14 37 30 15 0 0 -14 52 11 19 9 32 26 264 -24 -15 0 15 -14 44 7 -15 23 50 -14 20 38 16 0 0 -14 35 23 19 9 34 25 263 -25 -14 43 26 -14 27 19 -15 7 1 -14 3 51 17 0 0 -14 18 40 19 9 35 24 263 -26 -14 26 43 -14 10 37 -14 50 17 -13 47 9 18 0 0 -14 2 2 19 9 37 23 263 -27 -14 10 6 -13 54 0 -14 33 39 -13 30 32 19 0 0 -13 45 31 19 9 38 22 262 -28 -13 53 34 -13 37 28 -14 17 6 -13 14 2 20 0 0 -13 29 6 19 9 39 21 262 -29 -13 37 8 -13 21 3 -14 0 40 -12 57 37 21 0 0 -13 12 47 19 9 40 20 262 -30 -13 20 49 -13 4 45 -13 44 20 -12 41 20 22 0 0 -12 56 35 19 9 41 19 261 -31 -13 4 37 -12 48 33 -13 28 7 -12 25 9 23 0 0 -12 40 31 19 9 42 18 261 -32 -12 48 32 -12 32 29 -13 12 2 -12 9 6 24 0 0 -12 24 34 19 9 43 17 261 -33 -12 32 35 -12 16 33 -12 56 4 -11 53 10 25 0 0 -12 8 45 19 9 44 16 261 -34 -12 16 46 -12 0 44 -12 40 14 -11 37 22 26 0 0 -11 53 4 19 9 45 15 260 -35 -12 1 5 -11 45 4 -12 24 32 -11 21 43 27 0 0 -11 37 33 19 9 46 14 260 -36 -11 45 33 -11 29 32 -12 8 59 -11 6 12 28 0 0 -11 22 10 19 9 47 13 260 -37 -11 30 10 -11 14 10 -11 53 35 -10 50 51 29 0 0 -11 6 56 19 9 48 12 260 -37 -11 14 56 -10 58 57 -11 38 20 -10 35 39 30 0 0 -10 51 52 19 9 48 11 260 -38 -10 59 52 -10 43 53 -11 23 15 -10 20 36 31 0 0 -10 36 58 19 9 49 10 259 -39 -10 44 58 -10 28 59 -11 8 19 -10 5 43 32 0 0 -10 22 15 19 9 49 9 259 -40 -10 30 13 -10 14 16 -10 53 34 - 9 51 1 33 0 0 -10 7 41 19 9 50 8 259 -41 -10 15 40 - 9 59 43 -10 39 0 - 9 36 29 34 0 0 - 9 53 19 19 9 50 7 259 -42 -10 1 17 - 9 45 21 -10 24 36 - 9 22 8 35 0 0 - 9 39 8 19 9 51 6 259 -43 - 9 47 6 - 9 31 10 -10 10 23 - 9 7 58 36 0 0 - 9 25 8 19 9 51 5 259 -44 - 9 33 5 - 9 17 11 - 9 56 22 - 8 54 0 37 0 0 - 9 11 20 19 9 51 4 258 -45 - 9 19 17 - 9 3 23 - 9 42 32 - 8 40 13 38 0 0 - 8 57 44 19 9 51 3 258 -45 - 9 5 40 - 8 49 47 - 9 28 55 - 8 26 38 39 0 0 - 8 44 20 19 9 52 2 258 -46 - 8 52 16 - 8 36 24 - 9 15 29 .. .. .. 40 0 0 - 8 31 8 19 9 52 1 258 -47 - 8 39 4 - 8 23 12 - 9 2 16 .. .. .. Uncertainty in time = +/- 1 secs [Prediction of 2008 Nov 26.0] Data for the target star ------------------------ * name: TYC 5764-01436-1 * constellation : Aquarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 20 44 54.2728 DE: -12 06 40.911 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .020, .020 ) * V mag [mag]: 10.3 * B mag [mag]: 11.4 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (666) Desdemona approx. diameter [km]: 27 approx. diameter ["]: .015 distance from Earth [AU]: 2.54800 * orbital information: orbit source: Preston date of fit: 2008 Oct 29 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1002 number of rejected observations: 41 time covered by the observations: 1908 Jul 23 - 2008 Sep 30 1 sigma uncertainty ellipse (major, minor, PA): 0.014, 0.008, 76° remarks: * orbital elements for (666) Desdemona : Mean anomaly = 323.62686812 deg Arg. of pericenter = 173.95463546 deg Long. of node = 215.54083953 deg Inclination = 7.57968946 deg Eccentricity = 0.23652281 Semimajor axis = 2.59431232 AU Perihelion dist = 1.98069828 AU Mag: H = 10.60, G = 0.15 Epoch of elements : MJD 54805.79600000 TDT (2008 Dec 05.796) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Dec 5 666 Desdemona 19h 7.0m UT 10.3 20 44 54.273-12 6 40.91TYC 5764-01436-1 11.4 15.7 27 0.8 2.548 4.639 12.38 -50.4823 -12.115 -109.03 -22.49 19.1171 0.05713 -0.31717 19.71751 3.58497 0.00442 0.00153 2000 322.25977220081130.00000173.954635215.540840 7.5796890.23652281 2.5943123 1.980698310.9 5.00.15 RATE 2.3586890 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.025 0.022 86 2.46 0.021 0 54796.5020081205_1436-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Nov 26, 23:43 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org