THE OBSERVATIONS AND THEIR REDUCTION

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1 THE OBSERVATIONS AND THEIR REDUCTION Summary - Timing data of observations of lunar occultation made are reported to the International Lunar Occultation Centre (ILOC), by cooperators around the world. The data are reduced and a preliminary analysis for the coordinates of the Moon is made. The analysis gives the results in the Table 1 Solutions for lunation for the corrections to the lunar longitude and latitude ( and ) in the latest Japanese Ephemeris that is based on IAU (1976) system. 1. Observations You can see hereafter, the newest reduced results on this site. In the Table 2 Numbers of timing reports per year are listed. The positions of the stations with the telescopes belonging to each station, are listed in the Table 4 List of telescopes. It contains the station codes, the geographical coordinates of the stations and the place names. The positions of the observers/recorders related to station codes are listed in the Table 5 List of observers/recorders. 2. Method of reductions The International Astronomical Union (IAU) recommended in 1976 that new methods, theories and constants named IAU (1976) system should be adopted for astronomical ephemeris after ILOC accordingly has determined to adopt the new ephemeris for reduction and analysis of the lunar occultation data after January 1, The Japanese Ephemeris for this year, on which the reduction and analysis in this report are based, is compiled strictly in accordance with the IAU (1976) recommendation. The ephemeris adopts the dynamical time (TDT = TAI (sec.)) as the independent time variable instead of the ephemeris time. The arithmetic formulae (Mori, 1975, 1978), the basic data and the computer used for the reduction are described in the following schema A, B, and C, respectively. The observed stars are covered by the star catalogues. The reduction is made for the stars contained in ACRS, PPM, SAOC, AGK3, ZC or USNO (X, L, K, P, T, I, G) and others star catalogues, updated in the Table 3 Observations &Reductions. A. Formulae Observational residuals of angler distance between the moon s center and the star ( ) are calculated on the Besselian plane as : 2 2 { ( X ξ ) + ( Y η ) } h m, σ = sinπ κ (X, Y) and (, ) : rectangular coordinates of the Moon and the telescope on the Besselian plane, respectively, : equatorial horizontal parallax of the Moon, : the Moon's radius in the unit of the equatorial radius of the Earth, h m : limb correction.

2 a. Coordinates of the Moon x y z = Ω cosδ cosα m m 13( 90 δ, 90 + α ) cosec π cosδ m sinα m sinδ m, (, ) : apparent place of the star, (, m, m ) : apparent place of the Moon, calculated for each observation time, ( 90, 90 ) : transformation from the equatorial to the Besselian coordinates. Ω sinα cosα, = 0 sinδ cosδ cosα sinα 0 cosδ sinδ 0 0 ( 90 δ 90 + α ) , b. Coordinates of telescope ξ η ζ ( δ, 90 + α ) Ω (,x,y ) = Ω θ p p 1 a e u + dur v + dvr w + dw r, (-, x, y ) : transformation from the terrestrial to the celestial system, Ω 321 cos sin 1 x p 1 0, p, p sin cos 1 0 = θ θ θ θ y p x p y p 0 ( θ x y ), : Greenwich sidereal time at observation time, [T (UT1 UTC)] , : Greenwich sidereal time at 0 hour UT, T : observation time in UTC, UT1 UTC : excess rotation of the Earth over UTC, (x, y ) : polar motion, a : the Earth's equatorial radius ( m, IAU (1976) ), (u,v,w) : geocentric rectangular coordinates of the telescope. They are computed from geodetic coordinates through the following formula : u (N h h ) cos cos, v (N h h ) cos sin, w [N (1 e ) h h ] sin, N = ag / 1 e sin φ 2 2, (, ) : geodetic latitude and longitude (reduced for WGS 84, Leroy(1984)), h : height from the mean sea level, h : geoidal height (WGS 84), a : geodetic semi major axis of the Earth ( m, WGS 84),

3 (du, dv, dw ) : corrections due to atmospheric refraction, du h cos cos, dv h cos sin, dw h sin, h cot a cot a (meter), h : refraction height for a standard atmosphere, a : altitude of the star. c. Limb correction h m = sinπ sinπ 0 h m ( Ι,b, Π ), : equatorial horizontal parallax at the mean distance, h m : lunar profile at the mean distance, (l, b) : topocentric libration, : axis angle of the contact point,, sin tan, ξ x tan x = η y : semi diameter of the Moon, : topocentric position angle of the Moon's axis., B. Constants and basic data Constants and basic data are the same as those for the last year. a. Ephemeris Japanese Ephemeris for this year prepared by JHOD. b. Star catalogue H92 (1994) It is a composite catalogue in FK5 system, involving 32,221 zodiacal stars. It is in FK5 system and is compiled from FK5, FK5ext., ACRS, PPM, AGK3 and SAOC, in this order of priority. Pleiades, K and L star lists (FK5 system) whose original are provided by USNO are also used. c. Moon independent argument : TDT TAI (sec.), sinσ radius : k = 0 = , sinπ (sec.), sin (sec.) (IAU(1976)), limb correction : Watts' charts ( 1963 ), on magnetic tape prepared by HMNAO. 0

4 d. Earth orientation parameter rotation axis, (x, y ) and UT1-UTC : IERS Annual Report for this year. e. Station earth centered coordinates (u, v, w) : WGS 84, local geographical coordinates (,, h ) : reported values, geoidal height :OSU91. corrected for WGS 84. C. Computations Results of the reduction with O-C less than 2.0(sec.) are tabulated in the results tables which follow the Table 3, and the abbreviations in the results table are explained in the table Results of preliminary analysis Corrections to the Moon's longitude ( ) and latitude ( ) are derived by the following equation : σ σ L + B L B = σ The least squares calculations are made for every synodic month, in the lunation column. Observations with O-C more than 2.0(sec.) and observations of unknown stars were rejected in this analysis. The weights are assigned 1.0 for photoelectric observation and 0.25 for visual observation. TABLE 1. SOLUTIONS FOR LUNATIONS a) MEAN VALUES OF AND b) VALUES OF AND ( details ) References IERS: Annual Report, Paris, France. Inoue, K., Aoki, S., Kinoshita, H. and Soma, M.: 1983, Astronomy and Astrophysics, Vol. 128, p Kubo, Y.: 1971, Report of Hydrographic Researches, No.6, p.85. Lerch, F. J., Putney, B. H., Wagner, C. A. and Klosko, S. M.: Marine Geodesy Vol. 5, No. 2, p Leroy, C. F.: 1984, DMA Report "The impact of GRS 80 on DMA products". Mori, T.: 1975, Data Report of Hydrographic Observations, Series of Astronomy and Geodesy No.9, p. 40. Mori, T.: 1978, ibid. No. 12, p. 1. Watts, C.B. : 1963, Astr. Pap. Amer. Eph. No. 17.

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11 Table 2 shows the number of timing data reported to ILOC by the contributors around the world during the years from 1981 to as of now. TABLE 2. NUMBERS OF TIMING REPORTS PER YEAR Observed in Received until nowadays Total numbers of Reduction able 3 Number of Stations code Number of Telescopes Table 4 Number of Observers Table 5 Before

12 TABLE 3. OBSERVATIONS AND REDUCTIONS. Explanation Date Time Age Mag Star PH : Date of observation in UTC. : Observation time in UTC. The observations expressed in the unit of 0.1sec. are those made visually and the observations expressed in the unit of 0.01sec. are those made phot o-electrically. : Moon's age. : Magnitude of star. : Star name. The following abbreviations are used. A : the AGK3 catalogue D : the Durchmusterung catalogues (DM), G : the guide star catalogue. I : the Hippercos catalogue K : USNO K catalogue, P : Pleiades catalogue, R : the Robertson Zodiacal Catalogue (Z.C.), S : the SAO Catalogue, T : the tico catalogue X : USNO XZ star catalogue, : First character shows the phenomenon. D : disappearance, R : reappearance, F : flash, B : blink. Second character shows the lunar limb. D : dark limb event, B : bright limb event, G : grazing event, U : event during an eclipse of the Moon. STN TEL OBS REC O-C WH K-R K USNO SAO DM : Station code. : Telescope code. : Observer code. : Recorder code. : O-C of, limb correction already made. : Height of the lunar limb read from Watts' charts. The reading accuracy is within 0.05sec, except for the following two cases : a. Interpolation is doubtful due to some patterns of the charts. (Maximum error is within 0.2.sec.) b. Extrapolation is needed. There are cases where the extrapolation error may exceed 0.5sec. is attached to the tabular value when the estimated error is more than 0.3sec. : position angle of the event, referred to the direction of the Moon's motion. : Position angle of the star, measured counterclockwise from north at the Moon's center on the celestial sphere, as seen from the observer. : X : USNO XZ star catalog, P : Pleiades catalogue, K : USNO K catalogue, L : USNO L catalogue. : the SAO catalogue. : the Durchmusterung catalogues (DM).

13 S DD SF1L S DD TB X DD TOLA S DD TOGB S DD TOGA D DD TO S DD SO S DD TOGB S DD TOGA D DD TO S DD SO S DD SZ X DD SZ X DD SZ R 3529 DD SZ R 3529 DD SZ R 3529 DD SZ R 3529 DD SZ X DD TI X DD TI S DD TI S DD SZ * X DD SZ * S DD SZ X DD SZ * S DD SZ * X DD SZ6TB R 3536 DD SZ X DD T R 3536 DD SZ R 3536 DD SZ R 3536 DD SZ R 3536 DD SZ X DD SZ R 3536 DD SZ X DD SZ R 18 DD SC S DD SC S DD SC S DD TOGB X 569 DD TONLO R 60 DD TO S DD TO * S DD SO S DD SO * S DD TO S DD SO * D DD TO S DD SO X 609 DD ST X 988 DD SU X 988 DD SU2BD X 1005 DD SU2BD X 1010 DD SU2BD * X 1255 DD TAB * X 1246 DD TAB S DD SC X 1328 DD SD * X 1317 DD TAB X 1309 DD TAB * X 1308 DD TAB * S DD TB S DD TOGA S DD TOGA * X 1757 DD ST X 1775 DD TONLO X 1756 DD ST * D DD TO S DD TO S DD SO S DD TV2DA * S DD SO X 1782 DD TONLO S DD TO D DD TO S DD SO S DD SO R 188 DD TV2DA X 1794 DD ST S DD TOGB S DD TO S B SO S DD SV X 1823 DD ST X 1830 DD ST S DD SO X 1828 DD ST * X 2101 DD SZ4L X 2120 DD TU5N * S DD SUN X 2156 DD TU5N * X 2150 DD SZ4L * X 2191 DD TU X 2191 DD SU S DD SS X 2233 DD SU X 2274 DD SU S DD TB * S DD TB X 2547 DD TAB

14 S DD TB * X 2577 DD TAB S DD TB R 303 DD TV2DA X 2877 DD ST S DD ST X 2879 DD ST S DD ST * S DD SO S DD TOGA S DD TO S DD SO * S DD SO S DD TO S DD SO * S DD SO S DD TOAAY X 2903 DD ST S DD SO S DD ST S DD SO * R 308 DD TV2DA S DD SO X 2925 DD SO S DD SO X 2925 DD SO * X 2916 DD ST S DD TO S DD SO S DD SO * S DD SO S DD TO S DD SO X 2948 DD ST X 2945 DD ST X 2961 DD ST X 2968 DD ST S DD SO X 2995 DD ST X 3004 DD ST X 3006 DD ST S DD SZ X 3132 DD SZ4L X 3157 DD SZ4L X 3182 DD SZ4L X 3176 DD SZ4L * X 3220 DD SZ4L * S DD SZ * S DD SZ * S DD SZ * X 3276 DD SZ4L S DD SZ X 3532 DD SD * S DD TB * S DD TB R 398 DD SC * S DD TB X 3612 DD SD * S DD TB X 3623 DD SD X 3633 DD SD S DD SO X 3949 DD SO S DD SO * X 3974 DD SO X 4030 DD SO * R 477 DD T997A S DD SC X 4526 DD SD X 4545 DD SD X 4578 DD SD S DD SC X 4581 DD SD X 4666 DD SD * X 4677 DD SD X 4680 DD SD S DD SO S DD SO S DD SO S DD ST S DD ST X 5118 DD SO X 5169 DD SO X 5179 DD SO X 5429 DD SU X 5429 DD SU X 5429 DD TU X 5429 DD TUNAF X 5429 DD TU5N X 5474 DD TU5N X 5562 DD TU5N X 5563 DD TU5N X 5585 DD TIG X 5585 DD TU5N R 653 DD SA X 5714 DD SD R 658 DD SA R 658 DD SC X 5652 DD SU R 648 DD TUE

15 X 5741 DD TAB R 658 RB SC X 5741 DD SD X 5652 RB SU S DD SC X 5714 DD SU S DD TUNAJ X 5714 DD TU5B R 658 DD SUN R 658 DD SUN S DD SC X 5891 DD SD X 5908 DD SD X 5918 DD SD R 697 DD SC R 697 DD SA X 5936 DD SD X 6577 DD SU R 769 DD SU2BD R 783 DD TI S DD TI X 6719 DD TUNAF S DD TI X 6737 DD TUNAF R 790 DD TI X 6757 DD SU X 6766 DD SU X 6766 DD SU X 6766 DD SU X 6766 DD TUNAF X 6766 DD TIG X 6770 DD SU X 6774 DD TUNAF X 6796 DD SU X 6796 DD TUNAF X 6796 DD TU X 6796 DD TIG X 6796 DD SU X 6796 DD SU X 6800 DD SU X 6796 DD TU X 6800 DD TU R 793 DD SU2BD X 6925 DD TU R 808 DD SUN S DD SUN X 6989 DD TU R 826 DD SUN X 7021 DD TU S DD TB X 7110 DD TU R 847 DD SA R 847 RB SC S DD SO S DD ST X 9444 DD TAB X DU SZ R 1110 DG SUN R 1110 DG SUN R 1110 BG SUN R 1110 BG SUN R 1110 RG SUN R 1110 RG SUN X DU TU5N R 1125 DU T997A S DU SUN S DU SUN S DU SUN X DG TU5B X DU TU5D X DU TIG X DU TIG X DU TU5N X RU TZ X RU TZ X DU TI X DU TI R 1125 DG TU3U R 1125 DG TU3U X DU T R 1125 RG TU3U R 1125 DG TU3U R 1125 RG TU3U X RU TZ R 1125 DG TU3U R 1125 RG TU3U X DU TI R 1125 RG TU3U R 1125 DG TU3U R 1125 RG TU3U X RD SU S RU SUN X RU TI X RU TIG X RU TIG X DU SU X DU SZ X DU TZ X DU TZ S RU TZ

16 X DD SU X DU TUNA X DD SU S DU SUN S RU SUN R 1128 RB SZ R 1128 RB SZ X DU TU X DU SU X DU TU S DU SUN S DU SUN S DU SUN S DU TZ S DU SXEA S DU SUN S DU SUN X DU SZ X DU SU S DU SUN S DU SUN X DU TU5D X DU TIG X DU TIG X DU TZ X DU TZ X DU TU X DU TUNA X DD SU X DU TU3U X DU TU3U S DU TZ X DU SZ X DU SZ S DU TZ H RU TZ X DU TU3U X DU TU3U X DU SZ X DU TUNA R 1128 RU TZ X DU TUNA X RD SU S DU TZ X RU TU3U X RU TU3U X RU TIG X RU TU5N X RD SU X RU TU5N R 1296 RD T997A R 1298 RD T997A X RD TU5N X RD TU5N X RD TU5N R 1302 RD T997A X RD TU5N X RD TU5N X RD TU5N S RD SO S RD SO S RD SN S RD SO S RD SO S RD SO S RD SO S RD SO S RD SO X RD SZ X RD SZ X RD SZ X RD SZ S RD TB S RD TB X RD SZ X RD SZ X RD SU X RD SU X RD SU X RD SO X RD SO S RD SO S RD SO S RD SO S RD SO X RD SZ X RD SZ X DB SU S RD TB S RD TB S RD SO * S RD SO S RD SO S RD SO X RD SO S RD SO S RD SO X RD SO * S RD SO S RD SO

17 S RD SO X RD SO S RD SO X RD SZ X RD SZ * X RD SZ X RD SZ * X RD SZ X RD TUNAF S RD TB S RD SO S RD SO * S RD SO * S RD SO * S RD SO * S RD SO S RD SO S RD SO X RD SO S RD SO X RD SZ * H RD SZ X RD SZ * X RD SZ * X RD SZ * X RD SZ * H RD SZ H RD SZ X RD SZ X RD SZ S RD TB S RD TB * S RD SO S RD SO S RD SO S RD SO S RD SO S RD SO X RD SO S RD SO S RD SO S RD SO S RD SO S RD SO R 2035 RD TXEEH X DD SZ S RD TXEEH S RD SUN S RD TXEEH X DD SZ X DD SZ R 2043 RD SUN X RD TU R 2043 RD SU2BD R 2043 RD SU2P R 2043 RD TXEEH X DD SZ X RD TU X RD TU R 2047 RD SUN S RD SUN R 2047 RD SU2BD R 2047 RD SZ R 2047 RD TXEEH S RD SUN S RD SUN * S RD TXEEH S RD TXEEH * S RD SO S RD SO S RD SO * S RD SO S RD SO X RD SO X RD SO S RD SO S RD SO S RD TO S RD SO S RD SUN X RD TUNAF S RD SUN S RD SU X RD SU2BD S RD SO S RD TB S RD TB S RD SZ S RD TXEEH S DD SC S DD SC S DD SC S DD SC S DD SO S DD SO X DD SO X DD TAB X DD TAB X DD TAB S DG TD