Experimental study of atmospheric dispersion at Xinglong observatory

Atmospheric dispersion affects the observation quality of high-resolution imaging, photometry and spectrometry. It obtained atmospheric dispersion of four bands including 360-440 nm, 360-550 nm, 360-640 nm and 360-790 nm, according five zenith angles including 59.8, 57.6, 48.1, 47.8 and 36.4, with an 80 cm telescope at Xinglong Observatory. Four main sources of error were discussed in detail, and the accuracy of the measurement was about 0.6. Based on the zenith angle, the temperature, the humidity and the atmospheric pressure during observation, the theoretical value of atmospheric dispersion was calculated. The results of the calculation and measurement are consistent well with each other. In addition, it discussed the influence factors of atmospheric dispersion and their effect on high precision astronomical observation, and offered solutions for decreasing atmospheric dispersion for large telescope. The calculation and measured results show that:the observation method can achieve adequate precise result; and the effect of atmospheric dispersion is obvious for high-accuracy astronomical observation with large telescope, and corresponding auxiliary equipment is needed to decrease or correct atmospheric dispersion for different observation.