摘要:

AbstractAn adaptive filter for processing of astronomical images is developed and described. The filter recognizes the local signal resolution (which usually varies strongly across the image) and adapts its own impulse response to this resolution.

ISSN:0004-6337    

DOI:10.1002/asna.2113120602

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

ISSN:0004-6337    

DOI:10.1002/asna.2113120604

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractThree different orbits of BU 738 ‐ WDS 02189 S 3019, a close visual binary, have been proposed up to now: Finsen (1969, elliptic orbit), Finsen (1969, parabolic orbit) and Heintz (1984, elliptic). In the last few years, three micrometric observations [MS] and a single speckle‐interferometric observation [RN and MG]have been independently carried out with the ESO/GPO 38 cm astrograph and ESO/MPI 2.2 m telescope. From these measurements and a list of observations of C. E. Worley of the Naval Observatory a new provisional orbit is proposed. Whereas new observations will improve the presented solution, the validity of the first two orbits suggested by Finsen has definitively to be ruled out. The masses of the two components are estimated asMA= 1·09MȮ andMB= 1·01MȮ, respe

ISSN:0004-6337    

DOI:10.1002/asna.2113120605

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractSince the photometricUBVRIbroadband systems of Johnson and Morgan (1951, 1953), Johnson (1955, 1965) and Cousins (1976) were partly illdefined and have partly been modified over the years, their technical realization at different observatories is problematical. Large differences occur especially in measuring objects with peculiar spectra or strong lines. Therefore, firstly an accurate reconstruction of theUBVRIsystems of Johnson and the Cousins systems used at the South African Astronomical Observatory (SAAO), at Cerro Tololo Inter‐American Observatory (CTIO) and at Mount Stromlo/Siding Springs Observatory (MSSO) was attempted. The transmissions of the different bands, as well as the possible technical realizations are listed. The data of the Johnson system and the Cousins systems used at SAAO and MSSO were compiled from several publications and new measured transmission curves of the CTIO systems are given. The characteristic wavelengths λ0have been calculated for all systems. Using flux‐calibrated spectra of 75 early and late type stars in the wavelength range 3200‐8800 Å with a resolution of 10 Å, synthetic photometries of the four described systems and that of Bessell (1990) were derived. The transformation relations from the various systems to the original Johnson system are given in and have been compared to the defined relations. The accuracy of the synthetic photometry is ±0.02 mag inVand (B‐V), ±0.09 mag in (U‐B), and ±0.05 mag in (V‐R). The larger error in (U‐B) is due to the shortwave uncertainties of theUfilter transmissions and the missing spectral information because ofUVcut‐off of the spectra at λmin>3200 Å. The uncertainties in (V‐R) are due to the differentRfilters in the various systems. No synthetic photometry was possible to derive for theIband, because of missing spectra

ISSN:0004-6337    

DOI:10.1002/asna.2113120606

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

ISSN:0004-6337    

DOI:10.1002/asna.2113120608

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractIn two fields of the programme of the main meridional section of the Galaxy (MEGA) the proper motions for several thousands of stars were obtained in respect to a frame of background galaxies. An average proper motion accuracy of about 6 milliarcseconds per year was achieved from an analyses of MAMA measurements of Tautenburg Schmidt plates. The tautenburg and Lick mean proper motions for stars in the same magnitude range (15

ISSN:0004-6337    

DOI:10.1002/asna.2113120609

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractAn IHW narrow‐band photometry of comets P/Halley (1986 III), P/Giacobini‐Zinner (1985 XIII), P/Hartley‐Good (1985 XVII) and P/Thiele (1985 XIX) is presented. Molecular column densities and production rates of CN, C2, and C3species observed in the coma are calculated in the framework of the Haser model. A comparative analysis of gas and dust production rates in the atmospheres of these comets is given. The effective comet nuclear radii have been estimated by different methods: for comet P/Hartley‐GoodReff∼ 1·7 km, for P/ThieleReff∼ 2 km and for P/Giacobini‐Zinn

ISSN:0004-6337    

DOI:10.1002/asna.2113120610

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

ISSN:0004-6337    

DOI:10.1002/asna.2113120612

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractEs wird eine Übersicht gegeben über die im Jahr 1990 auf Tautenburger Schmidtplatten gefundenen Kleinen Planeten. Es wurden 561 Objekte beobachtet und für diese 2104 Positionen gerechnet. Es handelt sich um 430 Planetoiden mit provisorischer Bezeichnung, unter denen 364 neu vergebene Bezeichnungen sind, sowie um 131 numerierte Objekte. Für 160 Tautenburger Objekte wurden erste Bahnen gerechnet. Für 49 im Berichtszeitraum numerierte Planeten haben Tautenburger Positionen einen Beitrag geleistet. Darunter sind sechs in Tautenburg entdeckte Planetoiden (Tab

ISSN:0004-6337    

DOI:10.1002/asna.2113120613

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

ISSN:0004-6337    

DOI:10.1002/asna.2113120615

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY