Mono Move Help?

[Simon Pepper]

Hi All

I have moved from OSC to try mono and introducing filters and the EFW I cant get my stars right. I think its a back focus issue and I think I am too long (basing that on the image below as my stars are doing the top image not bottom one) even though I am as what's mentioned on ZWO... I guess firstly is someone able to confirm this is a back focus issue and then any pointers please. I am not sure how to get it back to 55mm by losing the 1mm spacer? Also can it be tested during the day or is it trial and error each clear night? Finally the mounting of the EFW to the camera is there a correct way could that be the issue? Thanks 

 

Bottom left

Top left

 

Top right

 

Bottom right

 

Edited October 23, 2021 by Simon Pepper

[Clarkey]

It would be useful to know exactly what your set up is to make a better judgement.  From the pictures it looks like you might be marginally too far away. I have used the ZWO set up and I have generally found it pretty close and not really needed to do much more. However, in both cases where it needed alteration mine was a fraction too close and was resolved with some spacers.

[Tommohawk]

That spacer setup is exactly what I have and it works fine for me - so your image seems odd. The filter type / thickness might make some difference, but not a lot. As Clarkey said, maybe some more info on what CC and scope you have would help. 

[Stickey]

How is the PA? I've seen images with similar issues caused by the PA being slightly out.