This isn't a direct answer to your question, but something that really needs to be pointed out about your example photograph.

The symptom you show in your example is NOT "star trails" in the usual sense, meaning they are caused by the earth's rotation during the exposure. Note that each star appears as two distinct points. This was caused by camera wobble, which is something you can fix.

In this example, the camera wobbled in such a way that with the earth's angular change superimposed, it first held fairly steady in one direction, then moved quickly, then held fairly steady again in another direction. The usual cause of such wobble is the motion from pressing the shutter button. A simple way to avoid that is to lock up the mirror, then use the self-timer to trigger the shutter. You only need a short self-timer delay, like 2 seconds. That gives the wobble from you touching the camera time to die down before the actual exposure.

Another thing to do is to hang a normal towel over the camera, of course being careful to not obstruct the light into the lens. The towel will dampen wobbles more quickly than they would on their own.

So to summarize:

1. Drape a towel over the camera.

2. Lock the mirror up.

3. Close the shutter on the view finder. Your picture doesn't seem to suffer from lack of this, but this is a good thing to do for long exposures.

4. Use the self-timer, 2 seconds minimum.