After I return home from work, the sky was a bit clear and the crescent Moon in the western horizon. So I brought out the Canon EF 100-400mm f/4.5-5.6 IS L lens and tested on it. Image was not bad and no chromatic aberration can be seen in the image. I use the autofocus system and turn off the Image Stabilization (IS) and focus IMHO is ok. Exposure was 1/250sec at ISO 400.
I use only a photo tripod to mount the Canon 500D together with the said lens and the result is satisfactory for me. I hope to be able to retest my portable system next time on the deep sky objects maybe next weekend if sky is ok.