The image of the famous Perseus Double cluster to the right was taken by Northern Optics using a Celestron Travelscope-70 prime focus with a Canon 1100D.
Expsoure was 10 seconds at 6400 ISO with the Travelscope-70 on a driven Skywatcher HEQ5 mount. A combination of light pollution and a mount not properly polar aligned were the two main factors for keeping the exposure relatively shirt to reduce star trailing and noise
But for such a low cost astro photography set up I think you will agree the results are good. Focus was done with magnified live view. 10 seconds is plenty of exposure time to show faint stars with a multitude of colours