[Carl]

Hi Guys
Thank's for the reply.
My tripod is pretty solid and i have not had any issues before. The series specs were 5min exposures x 20 with a 1 second interval.
If the tripod was too lightweight or things were not tight then i could expect random movement but this is uniformed movement; every second image has shifted by exactly the same amount. I put all the images into layers in Photoshop and checked the movement pattern.

I then did a test in my study late last night and increased the interval time to 5 seconds, This time the movement was random throughout the exposure list. My third test was better but this time i turned off image stabilsation and only allowed 2 seconds interval

This still doesn't account for the uniformed movement in the first series of exposures. I haven't changed anything from my earlier attempt at star trails that worked.

I'm at a loss, does the interval time have anything to do with it?

regards
Carl