Dorin-Lucian

I have installed the off axis guide, I am more than happy with it, I am testing it, but with a 15 minutes frame I pictured some great stars with no trails.

Thoroughly ^^

Thank you, that is very instructive, I haven't had time to go through all the settings yet, throughly. I am not sure how much it helps me with my problem. The guiding graph shows movements in both directions on Dec axis so if it were a backlash issue you'd see PHD2 struggling to compensate with repetitive and increasing signals in opposite direction. I mean you know when something is wrong with the tracking, it must be flexure ultimately.

The mount that I use is SW AZ-EQ6 Pro and Sw 305p Flextube main telescope. I didn't save a guidelog but I will once the sky gets cleared. Anyway I didn't receive any message from PHD2 that it cannot keep up with the mount movement as you sometimes get when you have a bad alignment. I have a picture with the guiding from an imaging session at the end of which the guiding was suboptimal. I have also attached the main camera view, (red) guidescope view with Barlow (yellow) and without it(green) Regarding the star selection I always play with exposure gain to maintain the guide camera in between 1 and 3 seconds exposure so I would not select a bad pixels for example. I know that dithering is good, but I want to track down the error. I saw after my post that the SharpCap setting was maximum dither step was 20 pixels with a minimum and maximum settle time of 5 and 60 seconds( I don't really understand this values) I you need other information, gladly, but I don't have a guidelog unfortunately. I did order an off axis guider which I will try ASAP

I have noticed that my telescope and the frames are drifting South constantly. Initially I thought it is the telescope flexure but the same drift happened imaging towards South (I.e Hamburger Galaxy) and North (Iris Nebula) despite the fact that gravitational forces should cause an opposite drift. My PA was reasonable (with 1 Star alignment the scope pointed to the target with 8 minutes error- still in the camera field of view). I use a 12 inch SW with a focal length of 1500mm and a 60mm guidescope with a 2.25X Barlow on it to achieve 540 mm focal length. I modified the guidescope so the most of the length it's not flexible and it is attached with screws on the main scope. My dark library for guiding camera is good(green on PHD2 and I choose the stars), and as I go through the main camera subs they are always drifting South and a bit West no matter the scope orientation. The overall drift in a 6 hours is about 6-7 minutes with a good guiding graph and the stars within 3 arcsec on the bull's eye target. Can I turn off the dithering option in PHD2? The lowest setting is 0.1 and changing tk this from 1 didn't change much. I use SharpCap as imaging program, can it be the cause by requesting dithering?