CCD漂移扫描观测星表ACR和CMC13的系统误差研究

对2000年前后发表的两部用CCD漂移扫描观测的天体测量星表——ACR(As- trometric calibration regions along the celestial equator)和CMC13(Carlsberg Merid- ian Catalog 13)进行误差分析.通过与UCAC2(The second U.S.Naval Observatory CCD Astrograph Catalog)星表比较,采用数值法,分析了误差的形式和量级大小.并从星表观测方式和数据归算的角度,分析了误差的主要可能来源.发现ACR和CMC13在赤纬方向存在明显的星等差,位置差值随赤经存在与CCD视场大小相近的周期性变化,位置差值随赤纬存在与归算带尺寸大小相近的系统性变化.

Analysis of Systematic Errors of Astrometric Catalogs Observed with CCD Drift Scanning

Compared with traditional photographic astrometry,CCD astrometry has the outstanding advantages of higher accuracy,efficient work and wider magnitude range.But it is endowed with some special errors,such as the systematic error related to magnitude due to the electric charge transfer efficiency.Magnitude equation is one of difficult problems in analysing systematic error of catalog. The technique of CCD drift scanning has got extensive application in space and ground based telescopes.The observation of CCD drift scanning,may cause the systematic errors associated with continuously moving of the tangent point on the celestial sphere.There has not been almost,however,error analysis on the catalogs observed with CCD drift scanning. In the article,the systematic errors of two astrometric catalogs,ACR(Astrometric calibration regions along the celestial equator)and CMC13(Carlsberg Meridian Telescope Catalog 13),which were observed with CCD drift scanning,are analyzed by comparing them with UCAC2(The second US Naval Observatory CCD Astrograph Catalog).It is found that there are significant magnitude equations,from-10 mas to 50 mas,in declination of ACR and CMC13.Waves with period approximated to the FOV of the drift scanning CCD exist in the systematic differences of positions in both UCAC2-ACR and UCAC2-CMC13. The possible sources of the errors are discussed. On the basis,the research topics about the errors in the high accuracy astrometric ob- servation by the 1.2m Schmidt telescope at Purple Mountain Observatory with CCD drift scanning are put forward.