IOTA/IOTA-ES occultation update for (906) Repsolda / TYC 2420-00396-1 event on 2008 May 21, 18:30 UT Visible from Africa Summary ------- On 2008 May 21 UT, the 70 km diameter asteroid (906) Repsolda will occult a 10.2 mag star in the constellation Auriga 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 5.3 mag to 15.5 mag (the magnitude of the asteroid) for at most 1.7 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: 76 * date and approx. time of event: 2008 May 21, 18:33 - 2008 May 21, 18:33 UT * midpoint of event [JD]: 2454608.27145417 * magnitude of target star: 10.2 * magnitude drop [mag]: 5.3 * estimated maximum duration [s]: 1.7 * Moon: 97 % sunlit, 166° distance * Sun: 33° distance * rough path description: Africa The occultation path -------------------- * approximate projected width [km]: 72 * 1 sigma uncertainty interval [path widths]: +/- 0.74 * 1 sigma uncertainty interval [seconds]: +/- 1.2 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .022 +/- .019) * 1 sigma uncertainty ellipse (major, minor, PA): ( .022", .019", 89° ) * approx speed of asteroid's shadow [km/s]: 41.1275 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 2420-00396-1 by 906 Repsolda on 2008 May 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 ' " Latitude Latitude Latitude Latitude 2 0 0 26 19 28 18 33 0 33 292 0 25 56 55 26 42 3 25 23 37 27 15 33 3 0 0 25 47 17 18 33 1 32 293 -2 25 24 41 26 9 55 24 51 19 26 43 29 4 0 0 25 14 41 18 33 3 31 293 -3 24 52 2 25 37 22 24 18 35 26 11 1 5 0 0 24 41 41 18 33 4 30 294 -4 24 19 0 25 4 25 23 45 29 25 38 8 6 0 0 24 8 18 18 33 6 29 294 -5 23 45 34 24 31 5 23 11 59 25 4 51 7 0 0 23 34 32 18 33 7 28 295 -6 23 11 46 23 57 21 22 38 7 24 31 12 8 0 0 23 0 25 18 33 9 26 295 -7 22 37 36 23 23 16 22 3 53 23 57 11 9 0 0 22 25 56 18 33 10 25 296 -8 22 3 5 22 48 50 21 29 19 23 22 48 10 0 0 21 51 8 18 33 11 24 296 -9 21 28 14 22 14 4 20 54 26 22 48 5 11 0 0 21 16 0 18 33 12 23 297 -10 20 53 5 21 38 58 20 19 13 22 13 2 12 0 0 20 40 34 18 33 14 22 297 -11 20 17 37 21 3 34 19 43 43 21 37 40 13 0 0 20 4 51 18 33 15 21 297 -12 19 41 52 20 27 52 19 7 56 21 2 1 14 0 0 19 28 52 18 33 16 20 298 -13 19 5 51 19 51 54 18 31 52 20 26 5 15 0 0 18 52 37 18 33 17 19 298 -15 18 29 35 19 15 41 17 55 35 19 49 54 16 0 0 18 16 8 18 33 18 18 298 -16 17 53 5 18 39 13 17 19 3 19 13 28 17 0 0 17 39 26 18 33 19 16 299 -17 17 16 23 18 2 32 16 42 19 18 36 49 18 0 0 17 2 33 18 33 20 15 299 -18 16 39 28 17 25 39 16 5 23 17 59 57 19 0 0 16 25 28 18 33 20 14 299 -19 16 2 23 16 48 36 15 28 17 17 22 54 20 0 0 15 48 14 18 33 21 13 300 -20 15 25 8 16 11 22 14 51 2 16 45 41 21 0 0 15 10 51 18 33 22 12 300 -21 14 47 46 15 34 0 14 13 39 16 8 19 22 0 0 14 33 22 18 33 22 11 300 -23 14 10 16 14 56 30 13 36 9 15 30 49 23 0 0 13 55 46 18 33 23 10 301 -24 13 32 41 14 18 54 12 58 34 14 53 14 24 0 0 13 18 6 18 33 24 8 301 -25 12 55 1 13 41 14 12 20 54 14 15 33 25 0 0 12 40 22 18 33 24 7 301 -26 12 17 17 13 3 30 11 43 12 13 37 48 26 0 0 12 2 37 18 33 24 6 301 -27 11 39 32 12 25 43 11 5 28 13 0 0 27 0 0 11 24 50 18 33 25 5 301 -28 11 1 46 11 47 56 10 27 43 12 22 12 28 0 0 10 47 4 18 33 25 4 302 -29 10 24 1 11 10 9 9 49 59 11 44 23 29 0 0 10 9 19 18 33 25 3 302 -31 9 46 18 10 32 23 9 12 18 11 6 35 30 0 0 9 31 37 18 33 25 1 302 -32 9 8 37 9 54 39 8 34 39 10 28 50 31 0 0 8 53 59 18 33 25 0 302 -33 8 31 1 9 17 0 .. .. .. 9 51 9 Uncertainty in time = +/- 1 secs [Prediction of 2008 Apr 9.0] Data for the target star ------------------------ * name: TYC 2420-00396-1 * constellation : Auriga * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 06 15 21.5594 DE: +31 45 41.063 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .017, .016 ) * V mag [mag]: 10.2 * B mag [mag]: 10.5 * Apparent position with proper motion RA(deg): 93.9736212550 DE(deg): 31.7606475977 * Equation of equinoxes (radians) : 0.000040464128956 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (906) Repsolda approx. diameter [km]: 70 approx. diameter ["]: .025 distance from Earth [AU]: 3.82600 * orbital information: orbit source: Preston date of fit: 2008 Apr 08 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 805 number of rejected observations: 59 time covered by the observations: 1916 Apr 11 - 2008 Feb 17 1 sigma uncertainty ellipse (major, minor, PA): 0.013, 0.009, 86° remarks: * orbital elements for (906) Repsolda : Mean anomaly = 121.42762343 deg Arg. of pericenter = 294.94683628 deg Long. of node = 40.35317178 deg Inclination = 11.79952962 deg Eccentricity = 0.08138010 Semimajor axis = 2.89584073 AU Perihelion dist = 2.66017692 AU Mag: H = 9.23, G = 0.15 Epoch of elements : MJD 54607.77100000 TDT (2008 May 21.771) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 May 21 906 Repsolda 18h 30.9m UT 10.2 6 15 21.559 31 45 41.06TYC 2420-00396-1 10.5 15.5 70 1.7 3.826 4.181 -1.86 -63.6516 31.762 -98.56 20.37 18.5149 0.00661 0.21139 23.19946 -0.80753 0.00304 0.00061 2000 119.8733802008 514.00000294.946836 40.353172 11.7995300.08138010 2.8958407 2.6601769 9.5 5.00.15 RATE 2.0000550 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.022 0.019 89 1.74 0.019 0 54565.5020080521_0396-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Apr 13, 03:45 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org