I am trying to make a movie showing the movement of comet Ison against the background stars during the coming apparition.

I would like to show the stars still and the comet moving among them. The only way I know how to do this is to set the interval for Earth's rotational period of 23h 56m 4s (close to that, anyway). When I do that the comet moves too quickly through the animation.

Is there a way to shorten the interval and not rotate the sky over the interval period? Perhaps there is a way to add extra frames to the animation between the intervals to slow it down?

Thanks in advance.

Roger in Jacksonville, FL