  In order to study the potential in high precision CCD astrometry of irregular
satellites, we have made experimental observations for Himalia, the sixth and
irregular satellite of Jupiter. A total of 185 CCD observations were obtained
by using the 2.4 m telescope and 1 m telescope at Yunnan Observatories over ten
nights. Preliminary analysis for the observations were made, including the
geometric distortion, the atmospheric refraction, and also the phase effect.
All positions of Himalia are measured relative to the reference stars from the
catalogue UCAC4 in each CCD field of view. The theoretical positions of Himalia
were retrieved from the IMCCE, while the positions of Jupiter were obtained
based on the planetary theory INPOP13C. The results show that the mean (O-C)
(observed minus computed) residuals are -0.004 and -0.002 arcsec in right
ascension and declination, respectively. The standard deviation of (O-C)
residuals are estimated at about 0.04 arcsec in each direction.
