Need help

It's collimation. Period.

Tony Gondola:

andrea tasselli:
It's collimation. Period.

+1

+1 plus round about 0.6mm more Spacer. With your filter you have 1/3 of the thickness of the filter more (if your filter is 2mm thick. Yout backfocus is now 55.6mm or a little bit more.

Thanks Everyone .

I did enter the serial number in the focus tab for the ocal collimator .
Im really off with my collimation . Maybe i did something wrong with the ocal . I Will check again ! 

Im using the starizona coma reducer . So at F3 , maybe it's harder

Need more details, but if your slightly defocused centered star looked good, then collimation is likely at least close.   If your left and right stars all look way off, then backfocus may be the culprit.   

Agreed, what did an in-focus image look like?   That will tell us a lot!

Your back-focus numbers don't seem right, with a 2600 mm screw to the wheel (and I assume that includes the wheel itself).   Is that supposed to be 26mm?  What camera are you using and what is the chip to front the camera body distance?    Assuming the 2600 is supposed to be 26, you're chip to camera front distance would have to be 6.5mm to equal 55mm  (26+22.5+6.5).  That seems too short. 

At f3, yes collimation and backfocus will be critical.

Please fill in the missing details and give us an in-focus image and we can help more.

I have the quattro 250 f4 and the Nexus corrector/reducer on the way, so I'm interested in the outcome here.

Sounds good.   It’s just that your original post was confusing.    

That’ll be what I’m using as well (except I have an OAG instead of a spacer).   

Do you have an in focus image with it?

Thanks Ashraf

So i did checked my collimation on capella and it was a perfect Donut when outfocus. Like i Said , the outside stars were not good . When focused, it was elongated.

So maybe it's tilt ?
I just changed today the compression ring . The original one was very bad . I got the Baader clicklock clamp .

But i tought it was suppose to be perfect Donuts all over the image for good collimation.

Here is 3h in HA . You can see that the big stars are not perfect . Thanks to Russell croman and blurx .

I dont have an image of my outfocus stars

Need an unprocessed (except for stretching) full resolution image

If a slightly defocused star in the center looks good, then collimation is likely OK
If collimation is good and the in-focus stars are symmetrically enlongated in the corners, then it's likely spacing
If collimation is good and the the in-focus stars are enlongated in one corner/side more than another, then it's likely tilt

Collimation and then tilt