System of astrometric databases of Pulkovo observatory.

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Observations of Solar system bodies

Machholz comet,
CCD image taken on 12.01.2005
Observations of Solar system bodies at the Pulkovo observatory have been performed since 1898. The purpose of these observations is the determination of precise coordinates of Solar system bodies, which is necessary for development and improvement of motion theories, and for studying the evolution of the Solar system. The main instruments are: Normal astrograph(D=330, F=3467 mm) and 26-inch refractor (D=650, F=10413 mm). Some other instruments were also used, such as short-focus double astrograph (D=100, F=700 mm) and lunar-planetary telescope (D=600 F=10000 mm). The latter was used for observations of satellites of Mars and Jupiter in Ordubad expedition of Pulkovo observatory in 1970s and 1980s. Only photographical observations were performed on these instruments until 1995. CCD observations with ST-6 camera started on 26-inch refractor in 1995. In December of 2004 CCD observations started on Normal astrograph (camera S2C-017AP, 1040x1160pix, field 16'x18'). Machholtz comet was the first observed object.

This table shows when each object was observed

 object                     years           object             years     
 Mars                       1960-1973       Pluto              1930-1994 
 Martian satellites    1973,1986,1988       Minor planets      1957-2005 
 Jupiter and sat.1-4        1974-1981       Halley comet       1986      
 Saturn and sat.1-8         1971-2005       Hale-Bopp comet    1997      
 Uranus                     1919-2004       Machholz comet     2004-2005 
 Neptune                    1899-1955                                    

Io and Europa, satellites of Jupiter
The database requires both equtorial coordinates (obtained using reference catalogs) and relative coordinates of satellites (relative to a planet or another satellite). Yale university catalog, AGK3, PPM, FOCAT were used as reference catalogs. In present time modern catalogs (HIPPARCOS, Tycho-2, UCAC-2) are used for image processing. Original technique of astrometric reduction of observations was developed in our laboratory. It is described in some articles.

Accuracy of observations given in this database is evaluated in comparison with motion theories ('O-C'). It requires both stochastic errors of observations and errors of motion theories. Inner accuracy of observations is evaluated by comparison of observations of one night, of one plate, or one CCD series. Systematic errors of observations and motion theories have been studied, results are given in these articles. Accuracy of photographical observations is about 0.2-0.3 arcsec for equatorial coordinates and 0.1-0.3 for relative coordinates of planetary satellites, depending on object and observational conditions. Accuracy of CCD observations is 1.5-2 times better (0.05-0.15 arcsec). General chracteristics of observations of every object, including evaluation of accuracy of observations, are given in this table.
Minor planet Juliana, mag=15.0

Minor planet Hebe, mag=10.1