Originally posted by frey71 I use K-70. I make photo with camera release delay. On photo stars seems like line. Exposure - 90s. I think that when the shutter is released, vibration occurs, which gives such an effect
More than likely you don't have a good calibration with astro tracer or are really pushing what astro tracer can do at the focal length and location in the sky. Shake on the tripod looks more like squiggles with stars. If this is only your first attempt with astro tracer or one of the first few calibration is what I would look at first. Other than than if you are near power lines, high current drawing appliances, electric motors, large amounts of iron or steel, etc will all affect astro tracer. I once setup on top of some buried power lines and didn't know it until morning, could not get astrotracer to work. It would either not calibrate, or if it would would be so far off I got exaggerated star trails. When calibrating, go well over the 180 degrees in each direction, smoothness of movement matters, as does keeping the rotation limited to only one axis. It takes a lot of practice to get good results and even then they can be limited. I can pretty consistently get a good calibration that will accurately track object for 20 seconds with a 400mm lens not too far from the ecliptic.