Back focus / Tilt advice

[Anthonyexmouth]

Finally getting around to doing my back focus spacing. NINA reported the curvature to be 2200 before tinkering and now its 50000. Not too sure what all the info in the NIA page means so if anyone can tell me if this looks ok or not and what I can do to improve. Stars in the top right and bottom left look a little dodgy. This is tilt, right? Also , does ASTAP agree with NINA? I'm reading it as ASTAP giving the right and left side wonky but NINA gives the diagonal.  Heres NINA, ASTAP and an image after tinkering. 

[Gary Clayton]

ASTAP flips the image so you can't compare them with out sorting out the correct orientation, I would say that you back focus is as close as your going to get it so just adjust the tilt as shown by NINA 

[Anthonyexmouth]

6 minutes ago, Gary Clayton said:

ASTAP flips the image so you can't compare them with out sorting out the correct orientation, I would say that you back focus is as close as your going to get it so just adjust the tilt as shown by NINA 

But doesn't ASTAP show the tilt to be left to right but NINA shows it on the diagonal, or am I reading it wrong? 

After stacking the results are ok, well better than I've ever had. Still need to work on this dualband processing. It's all so red. 

[Gary Clayton]

I have found that you can't always rely on what the software tells you and looking at NINA it shows that you have both left/right and top/bottom tilt, so I would tweak one axis at a time until you have it as low as possible. I have come to the conclusion after talking to other "SM90" users "pixel peepers" that the reducers-flatteners don't fully correct for a complete flat field no matter what FLO says, that being said your very close now.

Edited July 12, 2023 by Gary Clayton

[Anthonyexmouth]

17 minutes ago, Gary Clayton said:

I have found that you can't always rely on what the software tells you and looking at NINA it shows that you have both left/right and top/bottom tilt, so I would tweak one axis at a time until you have it as low as possible. I have come to the conclusion after talking to other "SM90" users "pixel peepers" that the reducers-flatteners don't fully correct for a complete flat field no matter what FLO says, that being said your very close now.

I'll probably live with this for a while. I need to get to grips with processing with this new filter. I saw a post the other day somewhere and can't remember where about an SM90 owner buying a 3rd party reducer because they didn't get on with the SM version. 

[Gary Clayton]

Good idea, just enjoy using and learning about it and by the time you have cropped your stacked image's, you won't notice any iffy stars.

[Anthonyexmouth]

1 hour ago, Gary Clayton said:

Good idea, just enjoy using and learning about it and by the time you have cropped your stacked image's, you won't notice any iffy stars.

Had a play with the Foraxx Palette for the first time. Subs were a little short, didn't check the sequence template before I started. 60x120s. Will got for longer next time. Need to get rid of that halo too. 

 

[Gary Clayton]

12 minutes ago, Anthonyexmouth said:

Had a play with the Foraxx Palette for the first time. Subs were a little short, didn't check the sequence template before I started. 60x120s. Will got for longer next time. Need to get rid of that halo too. 

 

Looking great for your attempt with the Foraxx Palette, I only managed to image for just over an hour last night on NGC6871 so it's a tad noisy