Dear Friends, no Northern Lights last night at our house, but the stars were out, so i was shooting star trails. These trails have gaps that resulted from neglecting to turn off the noise reduction feature in my camera.  There are two settings hidden in the camera menu that do noise reduction with high iso and one with long exposures.  When they are enabled, the camera tries to process the image between exposures and this processing takes as long as the exposure time, so if your exposure is 20 seconds, the camera delays the next exposure while it processes the noise reduction, resulting in a 20 second gap between exposures.  Lessons learned. til Tomorrow MJ