Hi, Here comes the last Arp which I took last weekend and it is Arp 29. Yes there seems to be a problem with the flat fielding on which I am already working :) This image is a stack of 14 times 10minutes subexposures and done with the same equipment as well as guiding side by side. Maybe I should raise the focal length of the guider from 630mm to 1260mm to get a better ratio to the 3000mm focal length of the Mewlon 250S. Thanks for looking Original view Image: http://rainerehlert.com/ARP/Arp29-140min.jpg Negative view Image: http://rainerehlert.com/ARP/Arp29-140min-inv.jpg I hope to do some more starting next weekend :)