My Pentax *ist DS is capable of producing streaky images. I did a stack of 15 images of Comet Lemmon a while back and ran it through DSS. No idea what caused the streaky background. All attempts to find a solution proved fruitless. No-one I talked to seemed to be able to offer any solutions.
http://www.iceinspace.com.au/forum/s...d.php?t=103394